27268161 Staadpro 2007 International Codes 2007 Complete

STAAD.Pro 2007

INTERNATIONAL DESIGN CODES

DAA037810-1/0001

A Bentley Solutions Center

www.reiworld.com

www.bentley.com/staad

http://www.reiworld.com/

STAAD.Pro 2007 is a suite of proprietary computer programs of Research Engineers,

a Bentley Solutions Center . Although every effort has been made to ensure the

correctness of these programs, REI will not accept responsibility for any mistake,

error or misrepresentation in or as a result of the usage of these programs.

Copyright attribution: ©2008, Bentley Systems, Incorporated. All rights reserved.

Trademark attribution: STAAD.Pro, STAAD.foundation, Section Wizard,

STAAD.Offshore and QSE are either registered or unregistered trademarks or

service marks of Bentley Systems, Incorporated or one of its direct or indirect

wholly-owned subsidiaries. Other brands and product names are trademarks of

their respective owners.

RELEASE 2007

Published February, 2008

About STAAD.Pro

STAAD.Pro is a general purpose structural analysis and design program with

applications primarily in the building industry - commercial buildings, bridges and

highway structures, industrial structures, chemical plant structures, dams, retaining

walls, turbine foundations, culverts and other embedded structures, etc. The program

hence consists of the following facilities to enable this task.

1. Graphical model generation utilities as well as text editor based commands for

creating the mathematical model. Beam and column members are represented

using lines. Walls, slabs and panel type entities are represented using triangular

and quadrilateral finite elements. Solid blocks are represented using brick

elements. These utilities allow the user to create the geometry, assign properties,

orient cross sections as desired, assign materials like steel, concrete, timber,

aluminum, specify supports, apply loads explicitly as well as have the program

generate loads, design parameters etc.

2. Analysis engines for performing linear elastic and pdelta analysis, finite element

analysis, frequency extraction, and dynamic response (spectrum, time history,

steady state, etc.).

3. Design engines for code checking and optimization of steel, aluminum a nd timber

members. Reinforcement calculations for concrete beams, columns, slabs and

shear walls. Design of shear and moment connections for steel members.

4. Result viewing, result verification and report generation tools for examining

displacement diagrams, bending moment and shear force diagrams, beam, plate

and solid stress contours, etc.

5. Peripheral tools for activities like import and export of data from and to other

widely accepted formats, links with other popular softwares for ni che areas like

reinforced and prestressed concrete slab design, footing design, steel connection

design, etc.

6. A library of exposed functions called OpenSTAAD which allows users to access

STAAD.Pro’s internal functions and routines as well as its graphical commands to

tap into STAAD’s database and link input and output data to third -party software

written using languages like C, C++, VB, VBA, FORTRAN, Java, Delphi, etc.

Thus, OpenSTAAD allows users to link in-house or third-party applications with

STAAD.Pro.

About the STAAD.Pro Documentation

The documentation for STAAD.Pro consists of a set of manuals as described below.

These manuals are normally provided only in the electronic format, with perhaps some

exceptions such as the Getting Started Manual which may be supplied as a printed

book to first time and new-version buyers.

All the manuals can be accessed from the Help facilities of STAAD.Pro. Users who

wish to obtain a printed copy of the books may contact Research Engineers. REI also

supplies the manuals in the PDF format at no cost for those who wish to print them on

their own. See the back cover of this book for addresses and phone numbers.

Getting Started and Tutorials : This manual contains information on the contents of

the STAAD.Pro package, computer system requirements, installation process, copy

protection issues and a description on how to run the programs in the package.

Tutorials that provide detailed and step-by-step explanation on using the programs are

also provided.

Examples Manual

This book offers examples of various problems that can be solved using the STAAD

engine. The examples represent various structural analyses and design problems

commonly encountered by structural engineers.

Graphical Environment

This document contains a detailed description of the Graphical User Interface (GUI) of

STAAD.Pro. The topics covered include model generation, structural analysis and

design, result verification, and report generation.

Technical Reference Manual

This manual deals with the theory behind the engineering calculations made by the

STAAD engine. It also includes an explanation of the commands available in the

STAAD command file.

International Design Codes

This document contains information on the various Concrete, Steel, and Alu minum

design codes, of several countries, that are implemented in STAAD.

The documentation for the STAAD.Pro Extension component(s) is available

separately.

Table of Contents

International Codes

Introduction i

Section 1 Australian Codes 1-

1A Concrete Design Per AS3600-2001 1-1

1A.1 Design Operations 1-1 1A.2 Section Types for Concrete Design 1-1 1A.3 Member Dimensions 1-1 1A.4 Design Parameters 1-2 1A.5 Slenderness Effects and Analysis Consideration 1-2 1A.6 Beam Design 1-3 1A.7 Column Design 1-5 1A.8 Slab/Wall Design 1-6

1B Steel Design Per AS 4100-1998 1-9

1B.1 General 1-9

1B.2 Analysis Methodology 1-10 1B.3 Member Property Specifications 1-10 1B.4 Built-in Steel Section Library 1-10 1B.5 Section Classification 1-15 1B.6 Member Resistances 1-15 1B.7 Design Parameters 1-17 1B.8 Code Checking 1-20 1B.9 Member Selection 1-20

1B.10 Tabulated Results of Steel Design 1-21

Section 2 British Codes 2-

2A Concrete Design Per BS8100 2-1

2A.1 Design Operations 2-1 2A.2 Design Parameters 2-1 2A.3 Slenderness Effects and Analysis Considerations 2-4 2A.4 Member Dimensions 2-4 2A.5 Beam Design 2-5

2A.6 Column Design 2-7 2A.7 Slab Design 2-8 2A.8 Shear Wall Design 2-10

2B Steel Design Per BS5950:2000 2-23

2B.1 General 2-23 2B.2 Analysis Methodology 2-25 2B.3 Member Property Specifications 2-25 2B.4 Built-in Steel Section Library 2-25 2B.5 Member Capacities 2-30

2B.6 Design Parameters 2-34 2B.7 Design Operations 2-46 2B.8 Code Checking 2-47 2B.9 Member Selection 2-48 2B.10 Tabulated Results of Steel Design 2-49 2B.11 Plate Girders 2-50 2B.12 Composite Sections 2-51 2B.13 Design of Tapered Beams 2-51

2B1 Steel Design Per BS5950:1990 2-55

2B1.1 General 2-55 2B1.2 Analysis Methodology 2-56 2B1.3 Member Property Specifications 2-56 2B1.4 Built-in Steel Section Library 2-56 2B1.5 Member Capacities 2-60 2B1.6 Design Parameters 2-65 2B1.7 Design Operations 2-73 2B1.8 Code Checking 2-74

2B1.9 Member Selection 2-74 2B1.10 Tabulated Results of Steel Design 2-75 2B1.11 Plate Girders 2-76 2B1.12 Composite Sections 2-77

2C Design Per BS5400 2-79

2C.1 General Comments 2-79 2C.2 Shape Limitations 2-79 2C.3 Section Class 2-80 2C.4 Moment Capacity 2-80

2C.5 Shear Capacity 2-80 2C.6 Design Parameters 2-81 2C.7 Composite Sections 2-82

2D Design Per BS8007 2-85

2D.1 General Comments 2-85 2D.2 Design Process 2-85 2D.3 Design Parameters 2-87 2D.4 Structural Model 2-87

2D.5 Wood & Armer Moments 2-88

2E Design Per British Cold Formed Steel Code 2-91

2E.1 General 2-91 2E.2 Cross-sectional Properties 2-91 2E.3 Design Procedure 2-92 2E.4 Design Equations 2-93

2E.5 Verification Problem 2-101

Section 3 Canadian Codes 3-

3A Concrete Design Per CSA Standard A 23.3-94 3-1

3A.1 Design Operations 3-1 3A.2 Section Types for Concrete Design 3-1 3A.3 Member Dimensions 3-1 3A.4 Slenderness Effects and Analysis Consideration 3-2

3A.5 Design Parameters 3-3 3A.6 Beam Design 3-4 3A.7 Column Design 3-7 3A.8 Slab/Wall Design 3-7

3B Steel Design Per CSA Standard CAN/CSA – S16-01 3-9

3B.1 General Comments 3-9 3B.2 Analysis Methodology 3-10 3B.3 Member Property Specifications 3-10 3B.4 Built-in Steel Section Library 3-10 3B.5 Section Classification 3-17

3B.6 Member Resistances 3-17 3B.7 Design Parameters 3-21 3B.8 Code Checking 3-23 3B.9 Member Selection 3-24 3B.10 Tabulated Results of Steel Design 3-25 3B.11 Verification Problems 3-26

3C Design Per Canadian Cold Formed Steel Code 3-41

3C.1 General 3-41 3C.2 Cross-Sectional Properties 3-41

3C.3 Design Procedure 3-42

3D Wood Design Per CSA Standard CAN/CSA-086-01 3-49

3D.1 General Comments 3-49 3D.2 Analysis Methodology 3-50 3D.3 Member Property Specifications 3-50 3D.4 Built-in Section Library 3-50 3D.5 Member Resistance 3-54

3D.6 Design Parameters 3-57 3D.7 Code Checking 3-59 3D.8 Member Selection 3-60 3D.9 Tabulated Results of Timber Design 3-60 3D.10 Verification Problems 3-61

Section 4 Chinese Codes 4-

4A Concrete Design Per GB50010-2002 4-1

4A.1 Design Operations 4-1 4A.2 Section Types for Concrete Design 4-1 4A.3 Member Dimensions 4-1 4A.4 Design Parameters 4-2 4A.5 Beam Design 4-2 4A.6 Column Design 4-6

4B Steel Design Per GBJ 50017-2003 4-11

4B.1 General 4-11 4B.2 Analysis Methodology 4-12

4B.3 Member Property Specifications 4-12 4B.4 Built-in Chinese Steel Section Library 4-12 4B.5 Member Capacities 4-17 4B.6 Combined Loading 4-18 4B.7 Design Parameters 4-18 4B.8 Code Checking 4-21 4B.9 Member Selection 4-22

Section 5 European Codes 5-

5A Concrete Design Per Eurocode EC2 5-1

5A.1 Design Operations 5-1 5A.2 Eurocode 2 (EC2) 5-1 5A.3 National Application Documents 5-2 5A.4 Material Properties and Load Factors 5-2 5A.5 Columns 5-3

5A.6 Beams 5-3 5A.7 Slabs 5-5 5A.8 Design Parameters 5-5

5B Steel Design Per Eurocode EC3 5-9

5B.1 General Description 5-9 5B.2 Design Parameters 5-14

5B.3 Tabulated Results of Steel Design 5-19 5B.3 Worked Examples 5-20 5B.4 User’s Examples 5-37

5C Timber Design Per EC5 Part 1-1 5-45

5C.1 General Comments 5-45 5C.2 Analysis Methodology 5-49 5C.3 Design Parameters 5-58 5C.4 Verification Problems 5-61

Section 6 Egyptian Codes 6-

6A Concrete Design Per ECCS205 6-1

6A.1 Design Operations 6-1 6A.2 Member Dimensions 6-1 6A.3 Design Parameters 6-2 6A.4 Slenderness Effects and Analysis Considerations 6-3 6A.5 Beam Design 6-3 6A.6 Column Design 6-6

6B Steel Design Per Egyptian Code # 205 6-9

6B.1 General Comments 6-9

6B.2 Allowable Stresses 6-9

6B.2.1 Axial Stress 6-10 6B.2.2 Bending Stress 6-11 6B.2.3 Shear Stress 6-13 6B.2.4 Combined Stress 6-13

6B.3 Stability Requirements 6-14 6B.4 Code Checking 6-14 6B.5 Member Selection 6-15

6B.6 Tabulated Results of Steel Design 6-15

Section 7 French Codes 7-

7A Concrete Design Per B A E L 7-1

7A.1 Design Operations 7-1 7A.2 Design Parameters 7-1

7A.3 Slenderness Effects and Analysis Consideration 7-1 7A.4 Member Dimensions 7-2 7A.5 Beam Design 7-3 7A.6 Column Design 7-5 7A.7 Slab/Wall Design 7-5

7B Steel Design Per the French Code 7-7

7B.1 General Comments 7-7 7B.2 Basis Of Methodology 7-8 7B.3 Member Capacities 7-8

7B.4 Combined Axial Force and Bending 7-9 7B.5 Design Parameters 7-9 7B.6 Code Checking and Member Selection 7-9 7B.7 Tabulated Results of Steel Design 7-9 7B.8 Built-in French Steel Section Library 7-12

Section 8 German Codes 8-

8A Concrete Design Per DIN 1045 8-1

8A.1 Design Operations 8-1 8A.2 Section Types for Concrete Design 8-1 8A.3 Member Dimensions 8-1 8A.4 Slenderness Effects and Analysis Considerations 8-2 8A.5 Beam Design 8-3 8A.6 Column Design 8-5 8A.7 Slab Design 8-6 8A.8 Design Parameters 8-7

8B Steel Design Per the DIN Code 8-11

8B.1 General 8-11

8B.2 Analysis Methodology 8-12 8B.3 Member Property Specifications 8-12 8B.4 Built-in German Steel Section Library 8-12 8B.5 Member Capacities 8-17 8B.6 Combined Loading 8-18 8B.7 Design Parameters 8-19 8B.8 Code Cecking 8-21

8B.9 Member Selection 8-22

Section 9 Indian Codes 9-

9A Concrete Design Per IS456 9-1

9A.1 Design Operations 9-1

9A.2 Section Types for Concrete Design 9-1 9A.3 Member Dimensions 9-1 9A.4 Design Parameters 9-2 9A.5 Slenderness Effects and Analysis Consideration 9-2 9A.6 Beam Design 9-3 9A.7 Column Design 9-7 9A.8 Bar Combination 9-14 9A.9 Wall Design in accordance with IS 456-2000 9-15

9A1 Concrete Design Per IS13920 9-27

9A1.1 Design Operations 9-27 9A1.2 Section Types for Concrete Design 9-27 9A1.3 Design Parameters 9-28 9A1.4 Beam Design 9-28 9A1.5 Column Design 9-32 9A1.6 Bar Combination 9-43

9B Steel Design Per IS900 9-49

9B.1 Design Operations 9-49 9B.2 General Comments 9-50 9B.3 Allowable Stresses 9-50

9B.3.1 Axial Stress 9-51 9B.3.2 Bending Stress 9-52 9B.3.3 Shear Stress 9-53 9B.3.4 Combined Stress 9-54

9B.4 Design Parameters 9-54 9B.5 Stability Requirements 9-54 9B.6 Truss Members 9-55 9B.7 Deflection Check 9-55

9B.8 Code Checking 9-55 9B.9 Member Selection 9-56 9B.10 Member Selection by Optimization 9-56 9B.11 Tabulated Results of Steel Design 9-57 9B.12 Indian Steel Table 9-59 9B.13 Column with Lacings and Battens 9-67

9C Steel Design Per IS802 9-71

9C.1 General Comments 9-71 9C.2 Allowable Stresses 9-71

9C.2.1 Axial Stress 9-72

9C.3 Stability Requirements 9-74 9C.4 Minimum Thickness Requirement 9-76

9C.5 Code Checking 9-76

9C.5.1 Design Steps 9-77

9C.6 Member Selection 9-78 9C.7 Member Selection by Optimization 9-78 9C.8 Tabulated Results of Steel Design 9-79 9C.9 Parameter Table for IS802 9-81 9C.10 Calculation of Net Section Factor 9-83 9C.11 Example Problem No. 28 9-85

9D Design Per Indian Cold Formed Steel Code 9-93

9D.1 General 9-93 9D.2 Cross-Sectional Properties 9-93 9D.3 Design Procedure 9-94

Section 10 Japanese Codes 10-

10A Concrete Design Per AIJ 10-1

10A.1 Design Operations 10-1

10A.2 Section Types for Concrete Design 10-1 10A.3 Member Dimensions 10-1 10A.4 Slenderness Effects and Analysis Consideration 10-2 10A.5 Beam Design 10-3 10A.6 Column Design 10-5 10A.7 Slab/Wall Design 10-7 10A.8 Design Parameters 10-8

10B Steel Design Per AIJ 10-11

10B.1 General 10-11 10B.2 Analysis Methodology 10-12

10B.3 Member Property Specifications 10-12 10B.4 Built-in Japanese Steel Section Library 10-12 10B.5 Member Capacities 10-18 10B.6 Combined Loading 10-22 10B.7 Design Parameters 10-23 10B.8 Code Checking 10-25

10B.9 Member Selection 10-26

Section 11 Mexican Codes 11-

11A Concrete Design Per MEX NTC 1987 11-1

11A.1 Design Operations 11-1 11A.2 Section Types for Concrete Design 11-1 11A.3 Member Dimensions 11-2 11A.4 Design Parameters 11-3 11A.5 Beam Design 11-6 11A.6 Column Design 11-10 11A.7 Column Interaction 11-11 11A.8 Column Design Output 11-12

11A.9 Slab Design 11-13

11B Steel Design Per Mexican Code 11-15

11B.1 General 11-15 11B.2 Limit States Design Fundamentals 11-16 11B.3 Member End Forces and Moments 11-17 11B.4 Section Classification 11-18 11B.5 Member in Axial Tension 11-18 11B.6 Axial Compression 11-19 11B.7 Flexural Design Strength 11-20

11B.8 Design for Shear 11-22 11B.9 Combined Compression Axial Force and Bending 11-22 11B.10 Combined Tension Axial Force and Bending 11-22 11B.11 Design Parameters 11-23 11B.12 Code Checking and Member Selection 11-27 11B.13 Tabulated Results of Steel Design 11-28

Section 12 Russian Codes 12-

12A Concrete Design Per Russian Code 12-1

12A.1 General 12-1 12A.2 Input Data 12-3 12A.3 Beams 12-10 12A.4 Columns 12-16 12A.5 2D (two dimensional) element (slabs, walls, shells) 12-21

12B Steel Design Per Russian Code 12-25

12B.1 General 12-25 12B.2 Axial tension members 12-26

12B.3 Axial compression members 12-26

12B.4 Flexural members 12-27 12B.5 Eccentrical compression/tension members 12-28 12B.6 Input Data 12-29 12B.7 Section selection and check results 12-45

Section 13 South African Codes 13-

13A Concrete Design Per SABS 0100-1 13-1

13A.1 Design Operations 13-1 13A.2 Design Parameters 13-1 13A.3 Member Dimensions 13-3 13A.4 Beam Design 13-4 13A.5 Column Design 13-6

13B Steel Design Per SAB Standard SAB0162–1: 1993 13-9

13B.1 General 13-9 13B.2 Analysis Methodology 13-10 13B.3 Member Property Specifications 13-10 13B.4 Built-in Steel Section Library 13-10 13B.5 Section Classification 13-16 13B.6 Member Resistances 13-16 13B.7 Design Parameters 13-20 13B.8 Code Checking 13-22

13B.9 Member Selection 13-24 13B.10 Tabulated Results of Steel Design 13-24 13B.11 Verification Problems 13-26

Section 14 American Aluminum Code 14-

14 Design Per American Aluminum Code 14-1

14.1 General 14-1 14.2 Member Properties 14-1 14.3 Design Procedure 14-3

14.4 Design Parameters 14-4 14.5 Code Checking 14-8 14.6 Member Selection 14-8

Section 15 American Transmission Tower Code 15-

15A Steel Design Per ASCE 10-97 15-1

15A.1 General Comments 15-1 15A.2 Allowable Stresses Per ASCE 10-97 15-2

15A.3 Critical conditions used as criteria to determine Pass/Fail status 15-3 15A.4 Design Parameters 15-3 15A.5 Code Checking and Member Selection 15-3

15B Steel Design Per ASCE Manuals And Reports 15-7

15B.1 General Comments 15-7 15B.2 Allowable Stresses Per ASCE (Pub.52) 15-8 15B.3 Design Parameters 15-9 15B.4 Code Checking and Member Selection 15-9 15B.5 Parameter Definition Table 15-10

Section 16 American A.P.I. Code 16-

16 Steel Design Per API 16-1

16.1 Design Operations 16-1 16.2 Allowables Per API Code 16-2

16.2.1 Tension Stress 16-2 16.2.2 Beam Stress 16-2

16.3 Stress due to Compression 16-3 16.4 Bending Stress 16-3

16.5 Combined Compression and Bending 16-4 16.6 Design Parameters 16-4 16.7 Code Checking 16-7 16.8 Member Selection 16-7 16.9 Truss Members 16-8 16.10 Punching Shear 16-8 16.11 Generation of the Geometry File 16-9 16.12 Chord Selection and Qf Parameter 16-10

16.13 External Geometry File 16-11 16.14 Limitations 16-12 16.15 Tabulated Results of Steel Design 16-13 16.16 The Two-Step Process 16-14

Introduction

This publication has been prepared to provide information

pertaining to the various international codes supported by STAAD.

These codes are provided as additional codes by Research

Engineers. In other words, they do not come with the standard

package. Hence, information on only some of the codes presented

in this document may be actually pertinent to the individual user's

package. Users may locate the information for the appropriate code

by referring to the Table of Contents shown on the previous few

pages.

This document is to be used in conjunction with the STAAD

Technical Reference Manual and the STAAD Examples Manual.

Effort has been made to provide some basic information about the

analysis considerations and the logic used in the design approach.

A brief outline of the factors affecting the design along with

references to the corresponding clauses in the codes is also

provided. Examples are provided at the appropriate places to

facilitate ease of understanding of the usage of the commands and

design parameters. Users are urged to refer to the Examples

Manual for solved problems that use the commands and features of

STAAD. Since the STAAD output contains references to the

clauses in the code that govern the design, users are urged to

consult the documentation of the code of that country for

additional details on the design criteria.

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Section 1

Australian Codes

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1-1

Concrete Design Per AS3600 - 2001

1A.1 Design Operations

STAAD has the capabilities for performing concrete design based

on the Australian code AS3600-2001 Australian Standard-Concrete

Structures.

1A.2 Section Types for Concrete Design

The following types of cross sections for concrete members can be

designed.

For Beams Prismatic (Rectangular & Square)

For Columns Prismatic (Rectangular, Square and Circular)

1A.3 Member Dimensions

Concrete members which will be designed by the program must

have certain section properties input under the MEMBER

PROPERTY command. The following example shows the required

input:

Section 1A

Concrete Design Per AS 3600

Section 1A

1-2

UNIT MM

MEMBER PROPERTY

1 3 TO 7 9 PRISM YD 450. ZD 250.

11 13 PR YD 350.

In the above input, the first set of members are rectangular (450

mm depth and 250mm width) and the second set of members, with

only depth and no width provided, will be assumed to be circular

with 350 mm diameter. It is absolutely imperative that the user not

provide the cross section area (AX) as an input.

1A.4 Design Parameters

The program contains a number of parameters which are needed to

perform the design. Default parameter values have been selected

such that they are frequently used numbers for conventional design

requirements. These values may be changed to suit the particular

design being performed. Table 1A.1 of this manual contains a

complete list of the available parameters and their default values.

It is necessary to declare length and force units as Millimeter and

Newton before performing the concrete design.

1A.5 Slenderness Effects and Analysis Consideration

Slenderness effects are extremely important in designing

compression members. There are two options by which the

slenderness effect can be accommodated. One option is to perform

an exact analysis which will take into account the influence of

axial loads and variable moment of inertia on member stiffness and

fixed end moments, the effect of deflections on moment and forces

and the effect of the duration of loads. Another option is to

approximately magnify design moments.

Section 1A

1-3

STAAD has been written to allow the use of the first option. To

perform this type of analysis, use the command PDELTA

ANALYSIS instead of PERFORM ANALYSIS. The PDELTA

ANALYSIS will accommodate the requirements of the second-

order analysis described by AS 3600, except for the effects of the

duration of the loads. It is felt that this effect may be safely

ignored because experts believe that the effects of the duration of

loads are negligible in a normal structural configuration.

Although ignoring load duration effects is somewhat of an

approximation, it must be realized that the evaluation of

slenderness effects is also by an approximate method. In this

method, additional moments are calculated based on empirical

formula and assumptions on sidesway.

Considering all of the above information, a PDELTA ANALYSIS,

as performed by STAAD may be used for the design of concrete

members. However the user must note that to take advantage of

this analysis, all the combinations of loading must be provided as

primary load cases and not as load combinations. This is due to the

fact that load combinations are just algebraic combinations of

forces and moments, whereas a primary load case is revised during

the P-delta analysis based on the deflections. Also, note that the

proper factored loads (like 1.5 for dead load etc.) should be

provided by the user. STAAD does not factor the loads

automatically.

1A.6 Beam Design

Beams are designed for flexure, shear and torsion. For all these

forces, all active beam loadings are prescanned to identify the

critical load cases at different sections of the beams. The total

number of sections considered is 13( e.g. 0.,.1,.2,.25,.3,.4,.5,.6,.7,.

75,.8,.9 and 1). All of these sections are scanned to determine the

design force envelopes.


Section 1A

1-4

Design for Flexure

Maximum sagging (creating tensile stress at the bottom face of the

beam) and hogging (creating tensile stress at the top face)

moments are calculated for all active load cases at each of the

above mentioned sections. Each of these sections is designed to

resist both of these critical sagging and hogging moments.

Currently, design of singly reinforced sections only is permitted. If

the section dimensions are inadequate as a singly reinforced

section, such a message will be permitted in the output. Flexural

design of beams is performed in two passes. In the first pass,

effective depths of the sections are determined with the

assumption of single layer of assumed reinforcement and

reinforcement requirements are calculated. After the preliminary

design, reinforcing bars are chosen from the internal database in

single or multiple layers. The entire flexure design is performed

again in a second pass taking into account the changed effective

depths of sections calculated on the basis of reinforcement

provided after the preliminary design. Final provisions of flexural

reinforcements are made then. Efforts have been made to meet the

guideline for the curtailment of reinforcements as per AS 3600.

Although exact curtailment lengths are not mentioned explicitly in

the design output (finally which will be more or less guided by the

detailer taking into account of other practical consideration), user

has the choice of printing reinforcements provided by STAAD at

13 equally spaced sections from which the final detailed drawing

can be prepared.

Design for Shear

Shear reinforcement is calculated to resist both shear forces and

torsional moments. Shear design is performed at 13 equally spaced

sections (0.to 1.) for the maximum shear forces amongst the active

load cases and the associated torsional moments. Shear capacity

calculation at different sections without the shear reinforcement is

based on the actual tensile reinforcement provided by STAAD

program. Two-legged stirrups are provided to take care of the

balance shear forces acting on these sections.

Section 1A

1-5

Example of Input Data for Beam Design

UNIT NEWTON MMS

START CONCRETE DESIGN

CODE AUSTRALIAN

FYMAIN 415 ALL

FYSEC 415 ALL

FC 35 ALL

CLEAR 25 MEM 2 TO 6

MAXMAIN 40 MEMB 2 TO 6

TRACK 1.0 MEMB 2 TO 9

DESIGN BEAM 2 TO 9

END CONCRETE DESIGN

1A.7 Column Design

Columns are designed for axial forces and biaxial moments at the

ends. All active load cases are tested to calculate reinforcement.

The loading which yields maximum reinforcement is called the

critical load. Column design is done for square, rectangular and

circular sections. By default, square and rectangular columns are

designed with reinforcement distributed on each side equally. That

means the total number of bars will always be a multiple of four

(4). This may cause slightly conservative results in some cases.

All major criteria for selecting longitudinal and transverse

reinforcement as stipulated by AS 3600 have been taken care of in

the column design of STAAD.

Example of Input Data for Column Design

UNIT NEWTON MMS


CODE AUSTRALIAN

FYMAIN 415 ALL

FC 35 ALL


Section 1A

1-6

CLEAR 25 MEMB 2 TO 6


DESIGN COLUMN 2 TO 6

END CONCRETE DESIGN

1A.8 Slab/Wall Design

To design a slab or wall, it must be modeled using finite elements.

The command specifications are in accordance with Chapter 2, and

Chapter 6 of the Technical Reference Manual.

Elements are designed for the moments Mx and My. These

moments are obtained from the element force output (see Section

3.8 of the Technical Reference Manual). The r einforcement

required to resist Mx moment is denoted as longitudinal

reinforcement and the reinforcement required to resist My moment

is denoted as transverse reinforcement. The parameters FYMAIN,

FC, MAXMAIN, MINMAIN and CLEAR listed in Table 1A.1 are

relevant to slab design. Other parameters mentioned in Table 1A.1

are not applicable to slab design.

LONG.

TRANS.

X

Y

Z

M

MM

Mx

y

x

y

Section 1A

1-7

Example of Input Data for Slab/Wall Design

UNIT NEWTON MMS


CODE AUSTRALIAN

FYMAIN 415 ALL

FC 25 ALL

CLEAR 40 ALL

DESIGN ELEMENT 15 TO 20

END CONCRETE DESIGN

Table 1A.1 Australian Concrete Design-AS 3600- Parameters

Parameter

Name

Default Value Description

FYMAIN* 450/mm2 Yield Stress for main reinforcing steel.

FYSEC* 450/mm2 Yield Stress for secondary reinforcing steel.

FC** 40 N/mm2 Concrete Yield Stress.

CLEAR 25 mm

40 mm

For beam members.

For column members

MINMAIN 10 mm Minimum main reinforcement bar size.

MAXMAIN 60 mm Maximum main reinforcement bar size.

MINSEC 8 mm Minimum secondary reinforcement bar size.

MAXSEC 12 mm Maximum secondary reinforcement bar size.

RATIO 4.0 Maximum percentage of longitudinal reinforcement in columns.

WIDTH ZD Width to be used for design. This value defaults to ZD as provided under MEMBER PROPERTIES.

DEPTH YD Total depth to be used for design. This value defaults to YD as provided under MEMBER PROPERTIES.


Section 1A

1-8

Table 1A.1 Australian Concrete Design-AS 3600- Parameters

Parameter

Name


TRACK 0.0 BEAM DESIGN:

For TRACK = 0.0, output consists of reinforcement details at START, MIDDLE and END.

For TRACK = 1.0, critical moments are printed in addition to TRACK 0.0 output.

For TRACK = 2.0, required steel for intermediate sections defined by NSECTION are printed in addition to TRACK 1.0 output.

COLUMN DESIGN:

With TRACK = 0.0, reinforcement details are printed.

REINF 0.0 Tied column. A value of 1.0 will mean spiral reinforcement.

Note: Once a parameter is specified, its value stays at that

specified number till it is specified again. This is the way STAAD

works for all codes.

* - applicable values are 250, 400, 450 and 500 as per Table 6.2.1 of

the AS 3600-2001 code.

** - applicable values are 20, 25, 32, 40, 50, and 65 as per Clause

6.1.1.1 of the AS 3600-2001 code.

1-9

Steel Design Per AS 4100 - 1998

1B.1 General

This section presents some general statements regarding the

implementation of the specifications recommended by Standards

Australia for structural steel design (AS 4100) in STAAD. The

design philosophy and procedural logistics are based on the

principles of elastic analysis and limit state method of design.

Facilities are available for member selection as well as code

checking.

The design philosophy embodied in this specification is based on

the concept of limit state design. Structures are designed and

proportioned taking into consideration the limit states at which

they would become unfit for their intended use. Two major

categories of limit-state are recognized - ultimate and

serviceability. The primary considerations in ultimate limit state

design are strength and stability, while that in serviceability is

deflection. Appropriate load and resistance factors are used so that

a uniform reliability is achieved for all steel structures under

various loading conditions and at the same time the chances of

limits being surpassed are acceptably remote.

In the STAAD implementation, members are proportioned to resist

the design loads without exceeding the limit states of strength,

stability and serviceability. Accordingly, the most economic

section is selected on the basis of the least weight criteria as

augmented by the designer in specification of allowable member

depths, desired section type, or other such parameters. The code

checking portion of the program checks whether code requirements

for each selected section are met and identifies the governing

criteria.

Section 1B

Steel Design Per AS 4100-1998

Section 1B

1-10

The following sections describe the salient features of the STAAD

implementation of AS 4100. A detailed description of the design

process along with its underlying concepts and assumptions is

available in the specification document.

1B.2 Analysis Methodology

Elastic analysis method is used to obtain the forces and moments

for design. Analysis is done for the primary and combination

loading conditions provided by the user. The user is allowed

complete flexibility in providing loading specifications and using

appropriate load factors to create necessary loading situations.

Depending upon the analysis requirements, regular stiffness

analysis or P-Delta analysis may be specified. Dynamic analysis

may also be performed and the results combined with static

analysis results.

1B.3 Member Property Specifications

For specification of member properties, the steel section library

available in STAAD may be used. The next section describes the

syntax of commands used to assign properties from the built-in

steel table. Member properties may also be specified using the

User Table facility. For more information on these facilities, refer

to the STAAD Technical Reference Manual.

1B.4 Built-in Steel Section Library

The following information is provided for use when the built -in

steel tables are to be referenced for member property specification.

These properties are stored in a database file. If called for, the

properties are also used for member design. Since the shear areas

are built into these tables, shear deformation is always considered

during the analysis of these members. An example of the member

property specification in an input file is provided at the end of this

section.

Section 1B

1-11

A complete listing of the sections available in the built-in steel

section library may be obtained by using the tools of the graphical

user interface.

Following are the descriptions of different types of sections.

UB Shapes

These shapes are designated in the following way.

20 TO 30 TA ST UB150X14.0

36 TO 46 TA ST UB180X16.1

UC Shapes

The designation for the UC shapes is similar to that for the UB

shapes.

25 TO 35 TA ST UC100X14.8

23 56 TA ST UC310X96.8

Welded Beams

Welded Beams are designated in the following way.

25 TO 35 TA ST WB700X115

23 56 TA ST WB1200X455

Welded Columns

Welded Columns are designated in the following way.

25 TO 35 TA ST WC400X114

23 56 TA ST WC400X303


Section 1B

1-12

Parallel Flange Channels

Shown below is the syntax for assigning names of channel

sections.

1 TO 5 TA ST PFC75

6 TO 10 TA ST PFC380

Double Channels

Back to back double channels, with or without a spacing between

them, are available. The letter D in front of the section name will

specify a double channel.

11 TA D PFC230

17 TA D C230X75X25 SP 0.5

In the above set of commands, member 11 is a back to back double

channel PFC230 with no spacing in between. Member 17 is a

double channel PFC300 with a spacing of 0.5 length units between

the channels.

Angles

Two types of specification may be used to describe an angle. The

standard angle section is specified as follows:

16 20 TA ST A30X30X6

The above section signifies an angle with legs of length 30mm and

a leg thickness of 6 mm. This specification may be used when the

local Z axis corresponds to the z-z axis specified in Chapter 2. If

the local Y axis corresponds to the z-z axis, type specification

"RA" (reverse angle) may be used.

17 21 TA RA A150X150X16

Section 1B

1-13

Double Angles

Short leg back to back or long leg back to back double angles can

be specified by means of input of the words SD or LD,

respectively, in front of the angle size. In case of an equal angle,

either SD or LD will serve the purpose.

33 35 TA SD A65X50X5 SP 0.6

37 39 TA LD A75X50X6

43 TO 47 TA LD A100X75X10 SP 0.75

Tubes (Rectangular or Square Hollow Sections)

Tubes can be assigned in 2 ways. In the first method, the

designation for the tube is as shown below. This method is meant

for tubes whose property name is available in the steel table. In

these examples, members 1 to 5 consist of a 2X2X0.5 inch size

tube section, and members 6 to 10 consist of 10X5X0.1875 inch

size tube section. The name is obtained as 10 times the depth, 10

times the width, and 16 times the thickness.

1 TO 5 TA ST TUB20202.5

6 TO 10 TA ST TUB100503.0

In the second method, tubes are specified by their dimensions. For

example,

6 TA ST TUBE DT 8.0 WT 6.0 TH 0.5

is a tube that has a height of 8 length units, width of 6 length

units, and a wall thickness of 0.5 length units. Only code checking,

no member selection, will be performed for TUBE sections

specified in this latter manner.


Section 1B

1-14

Pipes (Circular Hollow Sections)

Pipes can be assigned in 2 ways. In the first method, the

designation for the pipe is as shown below. This method is meant

for pipes whose property name is available in the steel table.

1 TO 5 TA ST PIP180X5

6 TO 10 TA ST PIP273X6.5

In the second method, pipe sections may be provided by specifying

the word PIPE followed by the outside and inside diameters of the

section. For example,

1 TO 9 TA ST PIPE OD 25.0 ID 20.0

specifies a pipe with outside diameter of 25 length units and inside

diameter of 20 length units. Only code checking, no member

selection, will be performed on pipes specified in this latter

manner.

Sample File Containing Australian Shapes

STAAD SPACE

UNIT METER KN

JOINT COORD

1 0 0 0 11 100 0 0

MEMB INCI

1 1 2 10

UNIT CM

MEMBER PROPERTIES AUSTRALIAN

* UB SHAPES

1 TA ST UB200X25.4

* UC SHAPES

2 TA ST UC250X89.5

* CHANNELS

3 TA ST PFC125

Section 1B

1-15

* DOUBLE CHANNELS

4 TA D PFC200

* ANGLES

5 TA ST A30X30X6

* REVERSE ANGLES

6 TA RA A150X150X16

* DOUBLE ANGLES - SHORT LEGS BACK TO BACK

7 TA SD A65X50X5 SP 0.6

* DOUBLE ANGLES - LONG LEGS BACK TO BACK

8 TA LD A100X75X10 SP 0.75

* TUBES (RECTANGULAR OR SQUARE HOLLOW SECTIONS)


* PIPES (CIRCULAR HOLLOW SECTIONS)

10 TA ST PIPE OD 25.0 ID 20.0

PRINT MEMB PROP

FINI

1B.5 Section Classification

The AS 4100 specification allows inelastic deformation of section

elements. Thus, local buckling becomes an important criterion.

Steel sections are classified as compact, non-compact or slender

depending upon their local buckling characteristics. This

classification is a function of the geometric properties of the

section. The design procedures are different depending on the

section class. STAAD determines the section classification for the

standard shapes and user specified shapes. Design is performed for

all three categories of section as mentioned above.

1B.6 Member Resistances

The member resistance is calculated in STAAD according to the

procedures outlined in AS 4100. This depends on several factors

such as members' unsupported lengths, cross-sectional properties,

support conditions and so on. The procedure adopted in STAAD

for calculating the member resistance is explained here.


Section 1B

1-16

Axial Tension

The criteria governing the capacity of tension members are based

on two limit states. Limit State of yielding of the gross section is

intended to prevent excessive elongation of the member. The

second limit state involves fracture at the section with the

minimum effective net area. The user through the use of the

parameter NSF (see Table 1B.1) may specify the net section area.

STAAD calculates the tension capacity of a member based on

these two limit states per Cl.7.1 and Cl.7.2 respectively of AS

4100. Parameters FYLD, FU, Kt and NSF are applicable for these

calculations.

Axial Compression

The compressive strength of members is determined based on

Clause 6.1 of the code. It is taken as the lesser of nominal section

capacity and nominal member capacity. Nominal section capacity

is a function of form factor (Cl.6.2.2), net area of the cross section

and yield stress of the material. The user through the use of the

parameter NSC (see Table 1B.1) may specify the net section area.

Note here, that this parameter is different from that corresponding

to tension. The program automatically calculates form factor.

Nominal member capacity is a function of nominal section

capacity and member slenderness reduction factor (Cl.6.3.3). Here

user is required to supply the value of b (Cl.6.3.3). Table 1B.1

gives the default value of this parameter (named ALB). The

effective length for the calculation of compressive strength may be

provided through the use of the parameters KY, KZ, LY and LZ

(see Table 1B.1).

Bending

The allowable bending moment of members is determined as the

lesser of nominal section capacity and nominal member capacity

(ref. Cl.5.1). The nominal section moment capacity is the capacity

to resist cross-section yielding or local buckling and is expressed

as the product of yield stress of material and effective section

modulus (ref. Cl.5.2). The effective section modulus is a function

of section type i.e. compact, non-compact or slender. The nominal

Section 1B

1-17

member capacity depends on overall flexural-torsional buckling of

the member (ref.Cl.5.3).

Interaction of axial force and bending

The member strength for sections subjected to axial compression

and uniaxial or biaxial bending is obtained through the use of

interaction equations. Here also the adequacy of a member is

examined against both section (ref. Cl.8.3.4) and member capacity

(ref.Cl.8.4.5). If the summation of the left hand side of the

equations, addressed by the above clauses, exceed 1.0 or the

allowable value provided using the RATIO parameter (see Table

1B.1), the member is considered to have FAILed under the loading

condition.

Shear

Shear capacity of cross section is taken as the shear yield capacity.

User may refer to Cl.5.11 in this context. Once the capacity is

obtained, the ratio of the shear force acting on the cross section to

the shear capacity of the section is calculated. If any of the ratios

(for both local Y & Z-axes) exceed 1.0 or the allowable value

provided using the RATIO parameter (see Table 1B.1), the section

is considered to have failed under shear.

1B.7 Design Parameters

The design parameters outlined in Table 1B.1 may be used to

control the design procedure. These parameters communicate

design decisions from the engineer to the program and thus allow

the engineer to control the design process to suit an application's

specific needs.

The default parameter values have been selected such that they are

frequently used numbers for conventional design. Depending on

the particular design requirements, some or all of these parameter

values may be changed to exactly model the physical structure.


Section 1B

1-18


specified number till it is specified again. This is the way

STAAD works for all codes.

Table 1B.1- Australian Steel Design Parameters

Parameter

Name


KY 1.0 K value for general column flexural buckling about the local Y-axis. Used to calculate slenderness ratio.

KZ 1.0 K value for general column flexural buckling about the local Z-axis. Used to calculate slenderness ratio.

LY Member Length Length for general column flexural buckling about the local Y-axis. Used to calculate slenderness ratio.

LZ Member Length Length for general column flexural buckling about the local Z-axis. Used to calculate slenderness ratio.

FYLD 250.0 MPa Yield strength of steel.

FU 500.0 MPa Ultimate strength of steel.

NSF 1.0 Net section factor for tension members.

MAIN 0.0 0.0 = Check slenderness ratio against the limits.

1.0 = Suppress the slenderness ratio check.

2.0 = Check slenderness ratio only for column buckling, not for web (See Section 3B.6, Shear)

TRACK 0.0 0.0 = Report only minimum design results.

1.0 = Report design strengths also.

2.0 = Provide full details of design.

DMAX 45.0 in. Maximum allowable depth (Applicable for member selection)

DMIN 0.0 in. Minimum required depth (Applicable for member selection)

RATIO 1.0 Permissible ratio of actual load effect to the

Section 1B

1-19

Table 1B.1- Australian Steel Design Parameters

Parameter

Name


design strength.

IST 1 Steel type - 1 - SR, 2 - HR, 3 - CF, 4 - LW, 5 - HW

PHI 0.9 Capacity reduction factor

NSC 1.0 Net section factor for compression members = An / Ag

(refer cl. 6.2.1)

ALM 1.0 Moment modification factor (refer cl. 5.6.1.1)

ALB 0.0 Member section constant (refer cl. 6.3.3)

KT 1.0 Correction factor for distribution of forces (refer cl. 7.2)

BEAM 0.0 0.0 = design only for end moments and those at locations specified by SECTION command.

1.0 = Perform design for moments at twelfth points along the beam.

UNT Member Length Unsupported length in bending compression of the top flange for calculating moment resistance.

UNB Member Length Unsupported length in bending compression of the bottom flange for calculating moment resistance.

DFF None (Mandatory for deflection

check)

“Deflection Length”/ Maxm. Allowable local deflection.

DJ1 Start Joint of member

Joint No. denoting start point for calculation of “deflection length”

DJ2 End Joint of member

Joint No. denoting end point for calculation of “deflection length”


Section 1B

1-20

1B.8 Code Checking

The purpose of code checking is to check whether the provided

section properties of the members are adequate. The adequacy is

checked as per AS 4100 requirements.

Code checking is done using forces and moments at every twelfth

point along the beam. The code checking output labels the

members as PASSed or FAILed. In addition, the critical condition,

governing load case, location (distance from the start joint) and

magnitudes of the governing forces and moments are also printed.

The extent of detail of the output can be controlled by using the

TRACK parameter.

Example of commands for CODE CHECKING:

UNIT NEWTON METER

PARAMETER

FYLD 330E6 MEMB 3 4

NSF 0.85 ALL

KY 1.2 MEMB 3 4

RATIO 0.9 ALL

CHECK CODE MEMB 3 4

Code checking cannot be performed on composite and prismatic

sections.

1B.9 Member Selection

The member selection process basically involves determination of

the least weight member that PASSes the code checking procedure

based on the forces and moments of the most recent analysis. The

section selected will be of the same type as that specified initially.

For example, a member specified initially as a channel will have a

Section 1B

1-21

channel selected for it. Selection of members whose properties are

originally provided from a user table will be limited to sections in

the user table.

Composite and prismatic sections cannot be selected.

Example of commands for MEMBER SELECTION:

UNIT NEWTON METER

PARAMETER

FYLD 330E6 MEMB 3 4

NSF 0.85 ALL

KY 1.2 MEMB 3 4

RATIO 0.9 ALL

SELECT MEMB 3 4

1B.10 Tabulated Results of Steel Design

Results of code checking and member selection are presented in a

tabular format. The term CRITICAL COND refers to the section of

the AS 4100 specification which governs the design.


Section 1B

1-22

Section 2

British Codes

Kjahds;akh

2-1

Concrete Design Per BS8110


It is strongly recommended that the user should perform new

concrete design using the RC Designer Module. The following is

provided to allow old STAAD files to be run.

STAAD has the capability of performing design of concrete

beams, columns and slabs according to BS8110. The 1997

revision of the code is currently implemented. Given the width

and depth (or diameter for circular columns) of a section, STAAD

will calculate the required reinforcement to resist the forces and

moments.



perform and control the design to BS8110. These parameters not

only act as a method to input required data for code calculations

but give the Engineer control over the actual design process.

Default values of commonly used parameters for conventional

design practice have been chosen as the basis. Table 2A.1 contains

a complete list of available parameters with their default values.




Section 2A


Section 2A

2-2

Table 2A.1 – British Concrete Design-BS8110-Parameters

Parameter

Name

Default

Value

Description

FYMAIN *460 N/mm2 Yield Stress for main reinforcement (For slabs, it is for reinforcement in both directions)

FYSEC *460N/mm2 Yield Stress for secondary reinforcement a. Applicable to shear bars in beams

FC * 30N/mm2 Concrete Yield Stress / cube strength

MINMAIN 8mm Minimum main reinforcement bar size Acceptable bar sizes: 6 8 10 12 16 20 25 32 40 50

MINSEC 8mm Minimum secondary bar size a. Applicable to shear reinforcement in beams

CLEAR * 20mm Clearance of reinforcement measured from concrete surface to closest bar perimeter.

MAXMAIN 50mm Maximum required reinforcement bar size Acceptable bars are per MINMAIN above.

SFACE *0.0 Face of support location at start of beam. (Only applicable for shear - use MEMBER OFFSET for bending )

EFACE *0.0 Face of support location at end of beam. (NOTE : Both SFACE & EFACE must be positive numbers.)

TRACK 0.0 0.0 = Critical Moment will not be printed with beam design report. Column design gives no detailed results.

1.0 = For beam gives min/max steel % and spacing. For columns gives a detailed table of output with additional moments calculated.

2.0 = Output of TRACK 1.0 List of design sag/hog moments and corresponding required steel area at each section of member

MMAG 1.0 Factor by which column design moments are magnified

NSECTION 10 Number of equally-spaced sections to be considered in finding critical moment for beam design. The upper limit is 20.

WIDTH *ZD Width of concrete member. This value default is as provided as ZD in MEMBER PROPERTIES.

DEPTH *YD Depth of concrete member. This value default is as provided as YD in MEMBER PROPERTIES.

Section 2A

2-3

Table 2A.1 – British Concrete Design-BS8110-Parameters

Parameter

Name

Default

Value

Description

BRACE 0.0 0.0 = Column braced in both directions. 1.0 = Column unbraced about local Z direction only 2.0 = Column unbraced about local Y direction only 3.0 = Column unbraced in both Y and Z directions

ELY 1.0 Member length factor about local Y direction for column design.

ELZ 1.0 Member length factor about local Z direction for column design.

SRA 0.0 0.0 = Orthogonal reinforcement layout without considering torsional moment Mxy -slabs only

-500 = Orthogonal reinforcement layout with Mxy used to calculate WOOD & ARMER moments for design.

A = Skew angle considered in WOOD & ARMER equations where A is the angle in degrees.

SERV 0.0 0.0 = No serviceability check performed. 1.0 = Perform serviceability check for beams as if they

were continuous. 2.0 = Perform serviceability check for beams as if they

were simply supported. 3.0 = Perform serviceability check for beams as if they

were cantilever beams. * Provided in current unit system


Section 2A

2-4

2A.3 Slenderness Effects and Analysis Considerations

STAAD provides the user with two methods of accounting for the

slenderness effects in the analysis and design of concrete

members. The first method is equivalent to the procedure

presented in BS8110 Part 1 1985 Section 3.8.2.2 In this section,

the code recognizes that additional moments induced by deflection

are present and states that these 'secondary' moments are

accounted for by the design formula in Section 3.8.3. This is the

method used in the design for concrete in STAAD.

Alternatively STAAD houses a PDELTA ANALYSIS facility,

which allows the effects of these second order moments to be

considered in the analysis rather than the design. In a PDELTA

analysis, after solving the joint displacements of the structure, the

additional moments induced in the structure are calculated. These

can be compared to those calculated using the formulation of

BS8110.


Concrete members that are to be designed by STAAD must have

certain section properties input under the MEMBER PROPERTIES

command. The following example demonstrates the required input:

UNIT MM

MEMBER PROPERTIES

*RECTANGULAR COLUMN 300mm WIDE X 450mm DEEP

1 3 TO 7 9 PRISM YD 450. ZD 300.

*CIRCULAR COLUMN 300mm diameter

11 13 PR YD 300.

* T-SECTION - FLANGE 1000.X 200.(YD-YB)

* - STEM 250(THICK) X 350.(DEEP)

Section 2A

2-5

14 PRISM YD 550. ZD 1000. YB 350. ZB 250.

In the above input, the first set of members are rectangular

(450mm depth x 300mm width) and the second set of members,

with only depth and no width provided, will be assumed to be

circular with 300mm diameter. Note that area (AX) is not provided

for these members. If shear area areas ( AY & AZ ) are to be

considered in analysis, the user may provide them along with YD

and ZD. Also note that if moments of inertias are not provided, the

program will calculate them from YD and ZD. Finally a T section

can be considered by using the third definition above.

2A.5 Beam Design

Beam design includes both flexure and shear. For both typ es of

beam action, all active beam loadings are scanned to create

moment and shear envelopes and locate the critical sections. The

total number of sections considered is ten, unless that number is

redefined with the NSECTION parameter. From the critical

moment values, the required positive and negative bar pattern is

developed with cut-off lengths calculated to include required

development length.

Shear design as per BS8110 clause 3.4.5 has been followed and the

procedure includes critical shear values plus torsional moments.

From these values, stirrup sizes are calculated with proper spacing.

The program will scan from each end of the member and provide a

total of two shear regions at each, depending on the change of

shear distribution along the beam. If torsion is present, the

program will also consider the provisions of BS8110 - Part 2 -

section 2.4. A table of shear and/or combined torsion is then

provided with critical shear.

Stirrups not bent up bars are assumed in the design. Table 2A.2

shows a sample output of an actual reinforcement pattern

developed by STAAD. The following annotations apply to Table

2A.2


Section 2A

2-6

1) LEVEL - Serial number of the bar centre which may

contain one or more bar groups.

2) HEIGHT - Height of bar level from the soffit of the beam

in relation to its local y axis.

3) BAR INFO - Reinforcement bar information specifying

number of bars and their size.

4) FROM - Distance from the start of the beam to the start

of the reinforcing bar.

5) TO - Distance from the start of the beam to the end

of the reinforcing bar.

6) ANCHOR - States whether anchorage, either a hook or

(STA,END) continuation, is needed at start (STA) or at the

end (END).

TABLE 2A.2- ACTUAL DESIGN OUTPUT

B E A M N O. 2 D E S I G N R E S U L T S - FLEXURE

LEN - 3854. mm FY - 460. FC - 30. SIZE - 300. X 600. mm

LEVEL HEIGHT BAR INFO FROM TO ANCHOR

mm mm mm STA END

1 29. 6- 8 MM 0. 3854. YES YES

CRITICAL POS MOMENT = 55.31 KN-M AT 1927. mm, LOAD 3

REQD STEEL = 261.mm2, ROW = 0.0014, ROWMX= 0.0400, ROWMN = 0.0013

MAX/MIN/ACTUAL BAR SPACING = 189./ 33./ 40. mm

2 565. 6- 8 MM 0. 3854. YES YES

CRITICAL NEG MOMENT = 55.31 KN-M AT 1927. mm, LOAD 4

REQD STEEL = 261.mm2, ROW = 0.0014, ROWMX= 0.0400, ROWMN = 0.0013

MAX/MIN/ACTUAL BAR SPACING = 189./ 33./ 40. mm

B E A M N O. 2 D E S I G N R E S U L T S - SHEAR

PROVIDE SHEAR AND TORSIONAL LINKS AS FOLLOWS

FROM - TO SHEAR TORSN LOAD LINK NO. SPACING mm C/C

mm kN kNm S T SIZE S T S+T S T S+T

END 1 1156 84.4 12 4 2 8 mm 3 5 9 335 199 116

2697 END 2 86.6 12 3 2 8 mm 3 5 9 335 199 116

EXTRA PERIPHERAL LONGITUDINAL TORSION STEEL: 402 mm2 EVENLY

DISTRIBUTED

* TORSIONAL RIGIDITY SHOULD CONFORM TO CL.2.4.3 - BS8110 *

Section 2A

2-7

2A.6 Column Design

Columns are designed for axial force and biaxial bending at the

ends. All active loadings are tested to calculate reinforcement. The

loading which produces maximum reinforcement is called the

critical load and is displayed. The requirements of BS8110 Part 1 -

section 3.8 are followed, with the user having control on the

effective length in each direction by using the ELZ and ELY

parameters as described in table 2A.1. Bracing conditions are

controlled by using the BRACE parameter. The program will then

decide whether or not the column is short or slender and whether it

requires additional moment calculations. For biaxial bending, the

recommendations of 3.8.4.5 of the code are considered.

Column design is done for square, rectangular and circular sections.

For rectangular and square sections, the reinforcement is always

assumed to be arranged symmetrically. This causes slightly

conservative results in certain cases. Table 2A.3 shows typical

column design results.

Using parameter TRACK 1.0, the detailed output below is obtained.

TRACK 0.0 would merely give the bar configuration, required steel

area and percentage, column size and critical load case.


Section 2A

2-8

TABLE 2A.3 -COLUMN DESIGN OUTPUT

C O L U M N No. 1 D E S I G N R E S U L T S

FY - 460. FC -30. N/MM2 RECT SIZE - 300. X 600. MM,

AREA OF STEEL REQUIRED = 875. SQ. MM.

BAR CONFIGURATION REINF PCT. LOAD LOCATION

8 12 MM 0.486 3 EACH END

(ARRANGE COLUMN REINFORCEMENTS SYMMETRICALLY)

BRACED /SHORT in z E.L.z = 4500 mm ( 3.8.1.3 & 5 )

BRACED /SLENDER in y E.L.y = 4500 mm ( 3.8.1.3 & 5 )

END MOMS. MZ1 = 1 MZ2 = 25 MY1 = 53 MY2 = 40

SLENDERNESS MOMTS. KNM: MOMZ = 0 MOMY = 2

DESIGN LOADS KN METER: MOM. = 64 AXIAL LOAD = 84

DESIGNED CAP. KN METER: MOM. = 64 AXIAL CAP.= 187

2A.7 Slab Design

Slabs are designed to BS8110 specifications. To design a slab, it

must first be modelled using finite elements. The command

specifications are in accordance with section 5.51.3 of the

Technical Reference Manual.

A typical example of element design output is shown in Table

2A.4. The reinforcement required to resist the Mx moment is

denoted as longitudinal reinforcement and the reinforcement

required to resist the My moment is denoted as transverse

reinforcement ( Fig. 4.1 ). The following parameters are those

applicable to slab design:

1. FYMAIN - Yield stress for all reinforcing steel

2. FC - Concrete grade

3. CLEAR - Distance from the outer surface to the edge of

the bar. This is considered the same on both

surfaces.

Section 2A

2-9

4. SRA - Parameter which denotes the angle of the

required transverse reinforcement relative to

the longitudinal reinforcement for the

calculation of WOOD & ARMER design

moments.

Other parameters, as shown in Table 2A.1 are not applicable.

WOOD & ARMER equations.

Ref: R H WOOD CONCRETE 1968 (FEBRUARY)

If the default value of zero is used for the parameter SRA, the

design will be based on the Mx and My moments which are the

direct results of STAAD analysis. The SRA parameter (Set

Reinforcement Angle) can be manipulated to introduce WOOD &

ARMER moments into the design replacing the pure Mx, My

moments. These new design moments allow the Mxy moment to be

considered when designing the section. Orthogonal or skew

reinforcement may be considered. SRA set to -500 will assume an

orthogonal layout. If however a skew is to be considered, an angle

is given in degrees measured anticlockwise (positive) from the

element local x-axis to the reinforcement bar. The resulting Mx*

and My* moments are calculated and shown in the design format.

The design of the slab considers a fixed bar size of 16mm in both

directions with the longitudinal bar being the layer closest to the

slab exterior face. Typical output is as follows:


Section 2A

2-10

TABLE 2A.4 -ELEMENT DESIGN OUTPUT

ELEMENT DESIGN SUMMARY-BASED ON 16mm BARS

MINIMUM AREAS ARE ACTUAL CODE MIN % REQUIREMENTS.

PRACTICAL LAYOUTS ARE AS FOLLOWS:

FY=460, 6No.16mm BARS AT 150mm C/C = 1206mm2/metre

FY=250, 4No.16mm BARS AT 250mm C/C = 804mm2/metre

ELEMENT LONG. REINF MOM-X /LOAD TRANS. REINF MOM-Y /LOAD

(mm2/m) (kN-m/m) (mm2/m) (kN-m/m)

WOOD & ARMER RESOLVED MOMENTS FOR ELEMENT: 13 UNITS: METER KN

LOAD MX MY MXY MX* MY*/Ma* ANGLE

1 0.619 0.249 0.000 2.226 1.855 30.000 TOP

1 0.619 0.249 0.000 0.000 0.000 30.000 BOTT

3 0.437 0.184 -0.007 1.586 1.358 30.000 TOP

3 0.437 0.184 -0.007 0.000 0.000 30.000 BOTT

13 TOP : 195. 2.23 / 1 195. 1.86 / 1

BOTT : 195. 0.00 / 3 195. 0.00 / 3

2A.8 Shear Wall Design

Purpose

Design of shear walls in accordance with BS 8110 has been added

to the features of the program.

Description

The program implements the provisions of BS 8110 for the design

of shear walls. It performs in-plane shear, compression, as well as

in-plane and out-of-plane bending design of reinforcing. The shear

wall is modeled by a single or a combination of Surface elements.

The use of the Surface element enables the design er to treat the

entire wall as one entity. It greatly simplifies the modeling of the

wall and adds clarity to the analysis and design output. The results

are presented in the context of the entire wall rather than

individual finite elements thereby allowing users to quickly locate

required information.

Section 2A

2-11

The program reports shear wall design results for each load

case/combination for user specified number of sections given by

SURFACE DIVISION (default value is 10) command. The shear

wall is designed at these horizontal sections. The output includes

the required horizontal and vertical distributed reinforcing, the

concentrated (in-plane bending) reinforcing and the link required

due to out-of-plane shear.

General format:

START SHEARWALL DESIGN CODE BRITISH FYMAIN f1 FC f2 HMIN f3 HMAX f4 VMIN f5 VMAX f6 EMIN f7 EMAX f8 LMIN f9 LMAX f10 CLEAR f11 TWOLAYERED f12 KSLENDER f13 DESIGN SHEARWALL LIST shearwall-list END

The next table explains parameters used in the shear wall design

command block above. Note: Once a parameter is specified, its

value stays at that specified number till it is specified again.

This is the way STAAD works for all codes.


Section 2A

2-12

SHEAR WALL DESIGN PARAMETERS

Parameter

Name


FYMAIN 460 Mpa Yield strength of steel, in current units.

FC 30 Mpa Compressive strength of concrete, in current units.

HMIN 6 Minimum size of horizontal reinforcing bars (range 6 mm – 36 mm). If input is 6 (integer number) the program will assume 6 mm diameter bar.

HMAX 36 Maximum size of horizontal reinforcing bars (range 6 mm – 36 mm). If input is 6 (integer number) the program will assume 6 mm diameter bar.

VMIN 6 Minimum size of vertical reinforcing bars (range 6mm – 36mm). If input is 6 (integer number) the program will assume 6 mm diameter bar.

VMAX 36 Maximum size of vertical reinforcing bars (range 6mm – 36mm). If input is 6 (integer number) the program will assume 6 mm diameter bar.

EMIN 6 Minimum size of vertical reinforcing bars located in edge zones (range 6mm – 36mm). If input is 6 (integer number) the program will assume 6 mm diameter bar.

EMAX 36 Maximum size of vertical reinforcing bars located in edge zones (range 6mm – 36mm). If input is 6 (integer number) the program will assume 6 mm diameter bar.

LMIN 6 Minimum size of links (range 6mm – 16mm). If input is 6 (integer number) the program will assume 6 mm diameter bar.

LMAX 16 Maximum size of links (range 6mm – 16mm). If input is 6 (integer number) the program will assume 6 mm diameter bar.

CLEAR 25 mm Clear concrete cover, in current units. TWOLAYERED 0 Reinforcement placement mode:

Section 2A

2-13


Parameter

Name


0 - single layer, each direction 1 - two layers, each direction

KSLENDER 1.5 Slenderness factor for finding effective height.

The following example starts from the definition of shear wall and

ends at the shear wall design.

Example

.

.

SET DIVISION 12

SURFACE INCIDENCES

2 5 37 34 SUR 1

19 16 65 68 SUR 2

11 15 186 165 SUR 3

10 6 138 159 SUR 4

.

.

.

SURFACE PROPERTY

1 TO 4 THI 18

SUPPORTS

1 7 14 20 PINNED

2 TO 5 GEN PIN

6 TO 10 GEN PIN

11 TO 15 GEN PIN

19 TO 16 GEN PIN

.

.


Section 2A

2-14

.

SURFACE CONSTANTS

E 3150

POISSON 0.17

DENSITY 8.68e-005

ALPHA 5.5e-006

.

.

START SHEARWALL DES

CODE BRITISH

UNIT NEW MMS

FC 25

FYMAIN 460

TWO 1

VMIN 12

HMIN 12

EMIN 12

DESIGN SHEA LIST 1 TO 4

END

Notes

1. Command SET DIVISION 12 indicates that the surface

boundary node-to-node segments will be subdivided into 12

fragments prior to finite element mesh generation.

2. Four surfaces are defined by the SURFACE INCIDENCES

command.

3. The SUPPORTS command includes the new support

generation routine. For instance, the line 2 TO 5 GEN PIN

assigns pinned supports to all nodes between nodes 2 and 5.

As the node-to-node distances were previously subdivided

by the SET DIVISION 12 command, there will be an

additional 11 nodes between nodes 2 and 5. As a result, all

13 nodes will be assigned pinned supports. Please note that

the additional 11 nodes are not individually accessible to the

user. They are created by the program to enable the finite

Section 2A

2-15

element mesh generation and to allow application of

boundary constraints.

4. Surface thickness and material constants are specified by the

SURFACE PROPERTY and SURFACE CONSTANTS,

respectively.

5. The shear wall design commands are listed between lines

START SHEARWALL DES and END. The CODE

command selects the design code that will be the basis for

the design. For British code the parameter is BRTISH. The

DESIGN SHEARWALL LIST command is followed by a

list of previously defined Surface elements intended as shear

walls and/or shear wall components.

Technical Overview

The program implements provisions of section 3.9 of BS 8110:Part

1:1997 and relevant provisions as referenced therein, for all active

load cases. The wall is designed as unbraced reinforced wall. The

following steps are performed for each of the horizontal sections

of the wall set using the SURFACE DIVISION command (see

Description above).

Checking of slenderness limit

The slenderness checking is done for out-of-plane direction. For

out-of-plane direction, the wall is assumed to be simply supported.

Hence, the provisions of clause 3.9.3.2.2 and 3.9.4.2 are

applicable. The default effective height is 1.5 times the clear

height. User can change the effective height. The limit for

slenderness is as per table 3.23 for unbraced wall, which is taken

as 30.

Design for in-plane bending (denoted by Mz in the shear wall

force output)

Walls are assumed to be cantilever beams fixed at their base and

carrying loads to the foundation.


Section 2A

2-16

Extreme compression fibre to centroid of tension (concentrated)

reinforcement distance, d, is taken as 0.8 horizontal length of the

wall. Flexural design of the wall is carried out in accordance with

the provisions of clause no. 3.4.4. The flexural (concentrated

vertical ) reinforcing is located at both ends (edges) of the len gth

of the wall. The edge reinforcement is assumed to be distributed

over a length of 0.2 times horizontal length on each side. This

length is inclusive of the thickness of the wall. Minimum

reinforcements are according to table 3.25.

Design for in-plane shear (denoted by Fxy in the shear wall

force output)

Limit on the nominal shear strength, v is calculated as per clause

no. 3.4.5.2.

Nominal shear strength of concrete is computed as per table 3.8.

The design shear stress is computed as per clause no. 3.4.5.12

taking into consideration the effect of axial load. The area of

reinforcement is calculated and checked against the minimum area

as per clause no. 3.12.7.4.

Design for compression and out-of-plane vertical bending

(denoted by Fy and My respectively in the shear wall force

output)

The wall panel is designed as simply supported (at top and

bottom), axially loaded with out-of-plane uniform lateral load,

with maximum moments and deflections occurring at mid-height.

Design is done as per clause no. 3.8.4 for axially loaded column

with uni-axial bending. The minimum reinforcement percentage is

as per table 3.25. The maximum reinforcement percentage of

vertical reinforcement is as per clause no. 3.12.6.3. Links if

necessary are calculated as per the provisions of clause 3.12.7.5.

Section 2A

2-17

Design for out-of-plane shear (denoted by Qy in the shear wall

force output)

The out-of-plane shear arises from out-of-plane loading. The

design shear stress is calculated as per 3.4.5.2 and shear strength

of concrete section is calculated as per table 3.8 considering

vertical reinforcement as tension reinforcement.

Shear reinforcements in the form of links are computed as per

table 3.7 and the provisions of clause 3.12.7.5.

Design for out-of-plane horizontal bending (denoted by Mx in

the shear wall force output)

The horizontal reinforcement already calculated from in -plane

shear is checked against the whole section subjected to out -of-

plane bending and axial load. The axial load in this case is the in-

plane shear. The section is again designed as axially loaded

column under uni-axial bending as per the provisions of clause

3.8.4. Extra reinforcement in the form of horizontal bars, if

necessary, is reported.

Shear Wall Design With Opening

The Surface element has been enhanced to allow design of shear

walls with rectangular openings. The automatic meshing algorithm

has been improved to allow variable divisions along wall and

opening(s) edges. Design and output are available for user selected

locations.

Description

Shear walls modeled in STAAD.Pro may include an unlimited

number of openings. Due to the presence of openings, the wall

may comprise up with different wall panels.

1. Shear wall set-up

Definition of a shear wall starts with a specification of the surface

element perimeter nodes, meshing divisions along node-to-node


Section 2A

2-18

segments, opening(s) corner coordinates, and meshing divisions of

four edges of the opening(s).

SURFACE INCIDENCE n1, ..., ni SURFACE s DIVISION sd1,

..., sdj -

RECOPENING x1 y1 z1 x2 y2 z2 x3 y3 z3 x4 y4 z4 DIVISION

od1, ..., odk

where:

n1, ..., ni - node numbers on the perimeter of the shear wall,

s - surface ordinal number,

sd1, ..., sdj - number of divisions for each of the node-to-node

distance on the surface perimeter,

x1 y1 z1 (...) - coordinates of the corners of the opening,

od1, ..., odk - divisions along edges of the opening.

Note:

If the sd1, ..., sdj or the od1, ..., odk list does not include all node-

to-node segments, or if any of the numbers listed equals zero, then

the corresponding division number is set to the default value (=10,

or as previously input by the SET DIVISION command).

Default locations for stress/force output, design, and design output

are set as follows:

SURFACE DIVISION X xd

SURFACE DIVISION Y yd

where:

xd - number of divisions along X axis,

yd - number of divisions along Y axis.

Section 2A

2-19

Note:

xd and yd represent default numbers of divisions for each edge of

the surface where output is requested. The output is provided for

sections located between division segments. For example, if the

number of divisions = 2, then the output will be produced for only

one section (at the center of the edge).

2. Stress/force output printing

Values of internal forces may be printed out for any user -defined

section of the wall. The general format of the command is as

follows:

PRINT SURFACE FORCE (ALONG ) (AT a) (BETWEEN d1, d2)

LIST s1, ...,si

where:

- local axis of the surface element (X or Y),

a - distance along the axis from start of the member to

the full cross-section of the wall, d1, d2 - coordinates in the direction orthogonal to ,

delineating a fragment of the full cross-section for

which the output is desired.**

s1, ...,si - list of surfaces for output generation

** The range currently is taken in terms of local axis. If the local

axis is directed away from the surface, the negative range is to be

entered.

Note:

If command ALONG is omitted, direction Y (default) is assumed.

If command AT is omitted, output is provided for all sections

along the specified (or default) edge. Number of sections will be

determined from the SURFACE DIVISION X or SURFACE


Section 2A

2-20

DIVISION Y input values. If the BETWEEN command is

omitted, the output is generated based on full cross-section width.

3. Definition of wall panels

Input syntax for panel definition is as follows:

START PANEL DEFINITION

SURFACE i PANEL j ptype x1 y1 z1 x2 y2 z2 x3 y3 z3 x4 y4 z4

END PANEL DEFINITION

where:

i - ordinal surface number,

j - ordinal panel number,

ptype - WALL

x1 y1 z1 (...) - coordinates of the corners of the panel

Note: Design of COLUMN and BEAM panels is currently not

available.

4. Shear wall design

The program implements different provisions of design of walls as

per code BS 8110. General syntax of the design command is as

follows:

START SHEARWALL DESIGN

(...)

DESIGN SHEARWALL (AT c) LIST s

TRACK tr

END SHEARWALL DESIGN

Parameter TRACK specifies how detailed the design output should

be:

Section 2A

2-21

0 - indicates a basic set of results data (default),

1 - full design output will be generated.

Note:

If the command AT is omitted, the design proceeds for all cross

sections of the wall or panels, as applicable, defined by the

SURFACE DIVISION X or SURFACE DIVISION Y input

values.

a. No panel definition.

Design is performed for the specified horizontal full cross-

section, located at a distance c from the origin of the local

coordinates system. If opening is found then reinforcement is

provided along sides of openings. The area of horizontal and

vertical bars provided along edges of openings is equal to

that of the respective interrupted bars.

b. Panels have been defined.

Design is performed for all panels, for the cross-section

located at a distance c from the start of the panel.


Section 2A

2-22

2-23

Steel Design Per BS5950:2000

2B.1 General

The design philosophy embodied in BS5950:2000 is built around

the concept of limit state design, used today in most modern steel

design codes. Structures are designed and proportioned taking into

consideration the limit states at which they become unfit for their

intended use. Two major categories of limit state are recognized -

serviceability and ultimate. The primary considerations in ultimate

limit state design are strength and stability while that in

serviceability limit state is deflection. Appropriate safety factors

are used so that the chances of limits being surpassed are

acceptably remote.

In the STAAD implementation of BS5950:2000, members are

proportioned to resist the design loads without exceeding the limit

states of strength and stability. Accordingly, the most economic

section is selected on the basis of the least weight criteria. This

procedure is controlled by the designer in specification of

allowable member depths, desired section type or other such

parameters. The code checking portion of the program checks that

code requirements for each selected section are met and identifies

the governing criteria.

The complete B.S.C. steel tables for both hot rolled and hollow

sections are built into the program for use in specifying member

properties as well as for the actual design process. See section

2B.4 for information regarding the referencing of these sections.

In addition to universal beams, columns, joists, piles, channels,

tees, composite sections, beams with cover plates, pipes, tubes and

angles, there is a provision for user provided tables.

Section 2B


Section 2B

2-24

STAAD.Pro 2006, has introduced the additional option to design

tapered I shaped (wide flange) beams according to Annex G of

BS5950. See section 2B.13 for a complete description.

Single Angle Sections

Angle sections are un-symmetrical and when using BS 5950:2000

table 25 we must consider four axes; two principal, u-u and v-v

and two geometric, a-a and b-b. In a TRACK 2.0 design output,

the „Buckling Calculations‟ displays results for the „v-v‟, „a-a‟ and

„b-b‟ axes. The effective length for the v-v axis, Lvv, is taken as

the LVV parameter or LY * KY, if not specified. The a -a and b-b

axes are determined by which leg of the angle is fixed by the

connection and should be specified using the LEG parameter, see

section 2B6.6 for more information on the LEG parameter. The

effective length in the a-a axis is taken as LY * KY and the

effective length in the b-b axis as LZ * KZ.

The following diagram shows the axes for angles which have been

defined with either an ST or RA specification and is connected by

its longer leg, i.e. a-a axis is parallel to the longer leg.

Local Z (u-u)

Local Y (v-v)

a

a

b

b

Local Z (v-v)

Local Y (u-u)

a

a

b

b

ST angle RA angle

and USER table angles

Section 2B

2-25










analysis results.




syntax of commands used to assign properties from the built -in




2B.4 Built-In Steel Section Library


steel tables are to be referenced for member property specificati on.




during the analysis of these members.

Almost all BSI steel sections are available for input. A complete

listing of the sections available in the built -in steel section library

may be obtained by using the tools of the graphical user interface.


Section 2B

2-26

Following are the descriptions of different types of section s

available:

Universal Beams, Columns And Piles

All rolled universal beams, columns and pile sections are

available. The following examples illustrate the designation

scheme.

20 TO 30 TA ST UB305X165X54

33 36 TA ST UC356X406X287

100 102 106 TA ST UP305X305X186

Rolled Steel Joists

Joist sections may be specified as they are listed in BSI-80 with

the weight omitted. In those cases where two joists have the same

specifications but different weights, the lighter section should be

specified with an "A" at the end.

10 TO 20 TA ST JO152X127

1 2 TA ST JO127X114A

Channel Sections

All rolled steel channel sections from the BSI table have been

incorporated in STAAD. The designation is similar to that of the

joists. The same designation scheme as in BSI tables may be used

with the weight omitted.

10 TO 15 TA ST CH305X102

55 57 59 61 TA ST CH178X76

Section 2B

2-27

Double Channels

Back to back double channels, with or without spacing between them,

are available. The letter "D" in front of the section name will specify

a double channel, e.g. D CH102X51, D CH203X89 etc.

51 52 53 TA D CH152X89

70 TO 80 TA D CH305X102 SP 5.

(specifies a double channel with a spacing of 5 length units)

Tee Sections

Tee sections are not input by their actual designations, but instead

by referring to the universal beam shapes from which they are cut.

For example,

54 55 56 TA T UB254X102X22

(tee cut from UB254X102X22)

Angles

All equal and unequal angles are available for analysis. Two types

of specifications may be used to describe an angle section, either a

standard, ST specification or reversed angle, RA specification.

Note, however, that only angles specified with an RA specification

can be designed.

The standard angle section is specified as follows:

15 20 25 TA ST UA200X150X18


Section 2B

2-28

This specification may be used when the local STAAD z-axis

corresponds to the V-V axis specified in the steel tables. If the

local STAAD y-axis corresponds to the V-V axis in the tables,

type specification "RA" (reverse angle) may be used.

35 TO 45 TA RA UA200X150X18

Double Angles


be specified by inputting the word SD or LD, respectively, in front

of the angle size. In case of an equal angle, either LD or SD will

serve the purpose. For example,

14 TO 20 TA LD UA200X200X16 SP 1.5

23 27 TA SD UA80X60X6

"SP" denotes spacing between the individual angle

sections.

Note that if the section is defined from a Double Angle User

Table, then the section properties must be defined with an 11 th

value which defines the radius of gyration about an individual

sections‟ principal v-v axis (See Technical Reference Manual, 5.19

User Steel Table Specification)


To designate circular hollow sections from BSI tables, use PIP

followed by the numerical value of diameter and thickness of the

section in mm omitting the decimal section of the value provided for

diameter. The following example will illustrate the designation.

10 15 TA ST PIP213.2

(specifies a 21.3 mm dia. pipe with 3.2 mm wall thickness)

Section 2B

2-29

Circular hollow sections may also be provided by specifying the

outside and inside diameters of the section. For example,


(specifies a pipe with outside dia. of 25 and inside dia. of

20 in current length units)

Only code checking and no member selection will be performed if

this type of specification is used.


Designation of tubes from the BSI steel table is illustrated below:

TUB 400 200 12.5

Example: 15 TO 25 TA ST TUB160808.0

Tubes, like pipes, can also be input by their dimensions (Height,

Width and Thickness) and not by any table designations.


(a tube that has a height of 8, a width of 6, and a wall

thickness of 0.5 length units)

Note that only code checking and no member selection is

performed for TUBE sections specified this way.

Square/Rectangular shape

Height (mm)

Thickness (mm)

Width (mm)


Section 2B

2-30

2B.5 Member Capacities

The basic measure of capacity of a beam is taken as the plastic

moment of the section. This is a significant departure from the

standard practice followed in BS449, in which the limiting

condition was attainment of yield stress at the extreme fibres of a

given section. With the introduction of the plastic moment as the

basic measure of capacity, careful consideration must be given to

the influence of local buckling on moment capacity. To assist this,

sections are classified as either Class 1, plastic, Class 2, compact,

Class 3, semi-compact or Class 4, slender, which governs the

decision whether to use the plastic or the elastic moment capacity.

The section classification is a function of the geometric properties

of the section. STAAD is capable of determining the section

classification for both hot rolled and built up sections. In addition,

for slender sections, BS5950 recommends the use of a 'stress

reduction factor' to reduce the design strength. This factor is again

a function of the geometry of the section and is automatically

determined by STAAD for use in the design process.

Axial Tension

In members with axial tension, the tensile load must not exceed the

tension capacity of the member. The tension capacity of the

member is calculated on the basis of the effective area as outlined

in Section 4.6 of the code. STAAD calculates the tension capacity

of a given member per this procedure, based on a user supplied net

section factor (NSF-a default value of 1.0 is present but may be

altered by changing the input value - see Table 2B.1), proceeding

with member selection or code check accordingly. BS5950 does

not have any slenderness limitations for tension members.

Compression

Compression members must be designed so that the compression

resistance of the member is greater than the axial compressive

load. Compression resistance is determined accordin g to the

compressive strength, which is a function of the slenderness of the

Section 2B

2-31

gross section, the appropriate design strength and the relevant

strut characteristics. Strut characteristics take into account the

considerable influence residual rolling and welding stresses have

on column behaviour. Based on data collected from extensive

research, it has been determined that sections such as tubes with

low residual stresses and Universal Beams and Columns are of

intermediate performance. It has been found that I -shaped sections

are less sensitive to imperfections when constrained to fail about

an axis parallel to the flanges. These research observations are

incorporated in BS5950 through the use of four strut curves

together with a selection of tables to indicate which curve to use

for a particular case. Compression strength for a particular section

is calculated in STAAD according to the procedure outlined in

Annex C of BS5950 where compression strength is seen to be a

function of the appropriate Robertson constan t ( representing Strut

Curve) corresponding Perry factor, limiting slenderness of the

member and appropriate design strength.

A departure from BS5950:1990, generally compression members

are no longer required to be checked for slenderness limitations,

however, this option can be included by specifying a MAIN

parameter. Note, a slenderness limit of 50 is still applied on

double angles checked as battened struts as per clause 4.7.9.

Axially Loaded Members With Moments

In the case of axially loaded members with moments, the moment

capacity of the member must be calculated about both principal

axes and all axial forces must be taken into account. If the section

is plastic or compact, plastic moment capacities will constitute the

basic moment capacities subject to an elastic limitation. The

purpose of this elastic limitation is to prevent plasticity at working

load. For semi-compact or slender sections, the elastic moment is

used. For plastic or compact sections with high shear loads, the

plastic modulus has to be reduced to accommodate the shear loads.

The STAAD implementation of BS5950 incorporates the procedure

outlined in section 4.2.5 and 4.2.6 to calculate the appropriate

moment capacities of the section.


Section 2B

2-32

For members with axial tension and moment, the interaction

formula as outlined in section 4.8.2 is applied based on effective

tension capacity.

For members with axial compression and moment, two principal

interaction formulae must be satisfied – Cross Section Capacity

check (4.8.3.2) and the Member Buckling Resistance check

(4.8.3.3 ). Three types of approach for the member buckling

resistance check have been outlined in BS5950:2000 - the

simplified approach (4.8.3.3.1), the more exact approach

(4.8.3.3.2) and Annex I1 for stocky members. As noted in the

code, in cases where neither the major axis nor the minor axis

moment approaches zero, the more exact approach may be more

conservative than the simplified approach. It has been found,

however, that this is not always the case and STAAD therefore

performs both checks, comparing the results in order that the more

appropriate criteria can be used.

Additionally the equivalent moment factors, m x my and myx, can be

specified by the user or calculated by the program.

Members subject to biaxial moments in the absence of both tensile

and compressive axial forces are checked using the appropriate

method described above with all axial forces set to zero. STAAD

also carries out cross checks for compression only, which for

compact/plastic sections may be more crit ical. If this is the case,

COMPRESSION will be the critical condition reported despite the

presence of moments.

Shear Load

A member subjected to shear is considered adequate if the shear

capacity of the section is greater than the shear load on the

member. Shear capacity is calculated in STAAD using the

procedure outlined in section 4.2.3, also 4.4.5 and Annex H3 if

appropriate, considering the appropriate shear area for the section

specified.

Section 2B

2-33

Lateral Torsional Buckling

Since plastic moment capacity is the basic moment capacity used

in BS5950, members are likely to experience relatively large

deflections. This effect, coupled with lateral torsional buckling,

may result in severe serviceability limit state. Hence, lateral

torsional buckling must be considered carefully.

The procedure to check for lateral torsional buckling as outlined in

section 4.3 has been incorporated in the STAAD implementation

of BS5950. According to this procedure, for a member subjected to

moments about the major axis, the 'equivalent uniform moment' on

the section must be less than the lateral torsional buckling

resistance moment. For calculation of the buckling resistance

moment, the procedure outlined in Annex B.2 has been

implemented for all sections with the exception of angles. In

Annex B.2., the resistance moment is given as a function of the

elastic critical moment, Perry coefficient, and limiting equivalent

slenderness, which are calculated within the program; and the

equivalent moment factor, mLT, which is determined as a function

of the loading configuration and the nature of the load

(stabilizing, destabilizing, etc).

R. H. S Sections - Additional Provisions

Rectangular Hollow sections are treated in accordance with S.C.I.

recommendations in cases when the plastic axis is in the flange. In

such cases, the following expressions are used to calculate the

reduced plastic moduli:

Srx = (A*A/4(B-t))(1-n) [ 2D(B-t)/A + n-1 ]

for n>= 2t(D-2t)/A

Sry = (A*A/4(D-t))(1-n) [ 2B(D-t)/A + n-1 ]

for n>= 2t(B-2t)/A


Section 2B

2-34


Available design parameters to be used in conjunction with

BS5950 are listed in table 2B.1 along with their default values.

The following items should be noted with respect to their use.

1. (PY – Steel Design Strength )

The design parameter PY should only be used when a uniform

design strength for an entire structure or a portion thereof is

required. Otherwise the value of PY will be set according to

the stipulations of BS5950 table 9 in which the design strength

is seen as a function of cross sectional thickness for a

particular steel grade (SGR parameter) and particular element

considered. Generally speaking this option is not required and

the program should be allowed to ascertain the appropriate

value.

2. (UNL, LY and LZ - Relevant Effective Length)

The values supplied for UNL, LY and LZ should be real

numbers greater than zero in current units of length. They are

supplied along with or instead of UNF, KY and KZ (which are

factors, not lengths) to define lateral torsional buckling and

compression effective lengths respectively. Please note that

both UNL or UNF and LY or KY values are required even

though they are often the same values. The former relates to

compression flange restraint for lateral torsional buckling

while the latter is the unrestrained buckling length for

compression checks.

3. (TRACK - Control of Output Formats )

When the TRACK parameter is set to 0.0, 1.0 or 2.0, member

capacities will be printed in design related output (code check

or member selection) in kilonewtons per square metre.

TRACK 4.0 causes the design to carry out a deflection check,

usually with a different load list to the main code check. The

members that are to be checked must have the parameters,

DFF, DJ1 and DJ2 set.

Section 2B

2-35

An example of each TRACK setting follows:-

TRACK 0.0 OUTPUT STAAD CODE CHECKING - (BSI )

--------------------------- ******************************

ALL UNITS ARE - KNS METR (UNLESS OTHERWISE NOTED)

MEMBER TABLE RESULT/ CRITICAL COND/ RATIO/ LOADING/

FX MY MZ LOCATION

=================================================================

1 ST UB686X254X170 PASS BS-4.8.3.2 0.036 3

86.72 C 0.00 -22.02 4.50

---------------------------------


--------------------------- ******************************



FX MY MZ LOCATION

=================================================================

1 ST UB686X254X170 PASS BS-4.8.3.2 0.036 3

86.72 C 0.00 -22.02 4.50

CALCULATED CAPACITIES FOR MEMB 1 UNIT - kN,m SECTION CLASS 4

MCZ= 1141.9 MCY= 120.4 PC= 3451.5 PT= 5739.9 MB= 1084.1 PV= 1597.5

BUCKLING CO-EFFICIENTS m AND n : m = 1.000 n = 1.000

PZ= 5739.90 FX/PZ = 0.02 MRZ= 1141.9 MRY= 120.4


Section 2B

2-36

TRACK 2.0 OUTPUT STAAD.Pro CODE CHECKING - (BSI )

--------------------------- ***************************

ALL UNITS ARE - KN METE (UNLESS OTHERWISE NOTED)


FX MY MZ LOCATION

===================================================================

1 ST UB533X210X92 PASS BS-4.3.6 0.902 100

0.00 0.00 585.41 0.00

===================================================================

MATERIAL DATA

Grade of steel = S 275

Modulus of elasticity = 205 kN/mm2

Design Strength (py) = 275 N/mm2

SECTION PROPERTIES (units - cm)

Member Length = 325.00

Gross Area = 117.00 Net Area = 117.00

Major axis Minor axis

Moment of inertia : 55229.996 2389.000

Plastic modulus : 2360.000 356.000

Elastic modulus : 2072.031 228.285

Shear Area : 58.771 53.843

DESIGN DATA (units - kN,m) BS5950-1/2000

Section Class : PLASTIC

Major axis Minor axis

Moment Capacity : 649.0 94.2

Reduced Moment Capacity : 649.0 97.9

Shear Capacity : 969.7 888.4

BUCKLING CALCULATIONS (units - kN,m)

(axis nomenclature as per design code)

LTB Moment Capacity (kNm) and LTB Length (m): 649.00, 0.001

LTB Coefficients & Associated Moments (kNm):

Section 2B

2-37

mLT = 1.00 : mx = 1.00 : my = 1.00 : myx = 1.00

Mlt = 585.41 : Mx = 585.41 : My = 0.00 : My = 0.00

CRITICAL LOADS FOR EACH CLAUSE CHECK (units- kN,m):

CLAUSE RATIO LOAD FX VY VZ MZ MY

BS-4.2.3-(Y) 0.329 100 - 292.3 - - -

BS-4.3.6 0.902 100 - 292.3 - 585.4 -

BS-4.8.3.2 0.814 100 0.0 68.0 0.0 585.4 0.0

BS-4.8.3.3.1 1.027 100 0.0 - - 585.4 0.0

BS-4.8.3.3.2 0.902 100 0.0 - - 585.4 0.0

Annex I.1 0.902 100 0.0 - - 585.4 0.0

Torsion and deflections have not been considered in the design.

_________________________

4. (MX, MY, MYX and MLT – Equivalent Moment Factors)

The values for the equivalent moment factors can either be

specified directly by the user as a positive value between 0.4

and 1.0 for MX, MY and MYX and 0.44 and 1.0 for MLT.

The program can be used to calculate the values for the

equivalent moment factors by defining the design member with

a GROUP command (see the Technical Reference Manual

section 5.16 Listing of Members/Elements/Joints by

Specification of GROUPS). The nodes along the beam can

then be defined as the location of restraint points with J

settings.

Additionally for the MLT parameter, the joint can be defined

as having the upper flange restrained (positive local Y) with

the a U setting or the lower flange restrained (negative local

Y) with a L setting.


Section 2B

2-38

For example, consider a series of 5 beam elements as a single

continuous member as shown below:

To enable the steel design, the beam needs to be defined as a

group, called MainBeam:

START GROUP DEFINITION

MEMBER

_MainBeam 11 2 38 12 3

END GROUP DEFINITION

Note that this can be done in the GUI by selecting the beams and

clicking on the menu option:

„Tools | Create New Group…‟

Therefore, this 5 beam member has 6 joints such that: -

Joint 1 = Node 3

Joint 2 = Node 1

Joint 3 = Node 33

Section 2B

2-39

Joint 4 = Node 14

Joint 5 = Node 7

Joint 6 = Node 2

a. Consider MX, MY and MYX

Say that this member has been restrained in its‟ major axis

(local Y) only at the ends. In the minor axis (local Z) it has

been restrained at the ends and also at node number 33 (joint

3). For local flexural buckling, it has only been restrained at

its ends. Hence:-

For the major axis, local Y axis:-

MX _MainBeam J1 J6

For the minor axis, local Z axis:-

MY _ MainBeam J1 J3 J6

For the lateral flexural buckling, local X axis: -

MYX _ MainBeam J1 J6

b. Consider MLT

Say that this member has been restrained at its‟ ends against

lateral torsional buckling and the top flange has been

restrained at node number 33 (joint 3) and only the lower

flange at node number 7, (joint 5). Hence:-

MLT _MainBeam J1 T3 L5 J6

To split the beam into two buckling lengths for Ly at joint

14:-

MY _groupname J1 J4 J6


Section 2B

2-40

5. (LEG - Table 25 BS5950 for Fastener Control)

The slenderness of single and double angle, channel and tee

sections are specified in BS 5950 table 25 depending on the

connection provided at the end of the member. To define the

appropriate connection, a LEG parameter should be assigned

to the member.

The following table indicates the value of the LEG parameter

required to match the BS5950 connection definition: -

Clause LEG

4.7.10.2

Single Angle

(a) - 2 bolts short leg 1.0

long leg 3.0

(b) - 1 bolt short leg 0.0

long leg 2.0

4.7.10.3

Double Angle


long leg 7.0


long leg 6.0

(c) - 2 bolts long leg 1.0

short leg 5.0

(d) - 1 bolt long leg 0.0

short leg 4.0

4.7.10.4

Channels

(a) - 2 or more rows of bolts 1.0

(b) - 1 row of bolts 0.0

4.7.10.5

Tee Sections



For single angles, the slenderness is calculated for the

geometric axes, a-a and b-b as well as the weak v-v axis. The

effective lengths of the geometric axes are defined as:-

La = KY * KY

Lb = KZ * LZ

Section 2B

2-41

The slenderness calculated for the v-v axis is then used to

calculate the compression strength p c for the weaker principal

axis (z-z for ST angles or y-y for RA specified angles). The

maximum slenderness of the a-a and b-b axes is used to

calculate the compression strength p c for the stronger principal

axis.

Alternatively for single angles where the connection is not

known or Table 25 is not appropriate, by setting the LEG

parameter to 10, slenderness is calculated for the two principal

axes y-y and z-z only. The LVV parameter is not used.

For double angles, the LVV parameter is available to comply

with note 5 in table 25. In addition, if using double angles from

user tables, (Technical Reference Manual section 5.19) an

eleventh value, rvv, should be supplied at the end of the ten

existing values corresponding to the radius of gyration of the

single angle making up the pair.

6. (SWAY – Sway Loadcase)

This parameter is used to specify a load case that is to be

treated as a sway load case in the context of clause 4.8.3.3.4.

This load case would be set up to represent the “kampMs”

mentioned in this clause and the steel design module would add

the forces from this load case to the forces of the other load

case it is designed for.

Note that the load case specified with this parameter will not be

designed as a separate load case. The following is the correct

syntax for the parameter:-

SWAY

(load case number)

ALL

MEMBER (member list)

_(group name)

e.g.

SWAY 5 MEM 1 to 10

SWAY 6 _MainBeams


Section 2B

2-42

Table 2B.1 - British Steel Design – BS5950:2000 - Parameters

Parameter

Name

Default

Value

Description

CODE BS5950 Design Code to follow. See section 5.47.1 of the Technical Reference Manual.

SGR 0.0 Steel Grade per BS4360 0.0 = Grade S 275 1.0 = Grade S 355 2.0 = Grade S 460 3.0 = As per GB 1591 – 16 Mn

AD Depth at end/2

Distance between the reference axis and the axis of restraint. See G.2.3

PY * Set according to steel grade

(SGR)

Design strength of steel

KY 1.0 K factor value in local y - axis. Usually, this is the minor axis.

KZ 1.0 K factor value in local z - axis. Usually, this is the major axis.

LY * Member Length

Length in local y - axis (current units) to calculate (KY)(LY)/Ryy slenderness ratio.

LZ * Member Length

Length in local z - axis (current units) to calculate (KZ)(LZ)/Rzz slenderness ratio.

UNF 1.0 Factor applied to unsupported length for Lateral Torsional Buckling effective length per section 4.3.6.7 of BS5950.

UNL * Member Length

Unsupported Length for calculating Lateral Torsional Buckling resistance moment section 4.3.6.7 of BS5950.


SBLT 0.0 Identify Section type for section classification 0.0 = Rolled Section 1.0 = Built up Section 2.0 = Cold formed section

MAIN 0.0 Slenderness limit for members with compression forces, effective length/ radius of gyration, for a given axis:- 0.0 = Slenderness not performed. 1.0 = Main structural member (180) 2.0 = Secondary member. (250) 3.0 = Bracing etc (350)

Section 2B

2-43


Parameter

Name

Default

Value

Description

TRACK 0.0 0.0 = Suppress all member capacity info. 1.0 = Print all member capacities. 2.0 = Print detailed design sheet. 4.0 = Deflection Check (separate check to main select /

check code)

BEAM 3.0 0.0 = Design only for end moments or those locations specified by the SECTION command.

1.0 = Calculate forces and moments at 12th points along the member. Establish the location where Mz is the maximum. Use the forces and moments at that location. Clause checks at one location.

2.0 = Same as BEAM = 1.0 but additional checks are carried out for each end.

3.0 = Calculate moments at 12th points along the member. Clause checks at each location including the ends of the member.

LEG 0.0 Valid range from 0 – 7 and 10. See section 2B.6.5 for details. The values correspond to table 25 of BS5950 for fastener conditions.

LVV * Maximum of Lyy and Lzz

(Lyy is a term used

by BS5950)

Used in conjunction with LEG for Lvv as per BS5950 table 25 for double angles, note 5.

CB 1.0 1.0 = BS5950 per clause B.2.5 (continuous) to calculate Mb.

2.0 = To calculate Mbs (simple) as per Clause 4.7.7 as opposed to Mb.

DFF None (Mandatory

for deflection check,

TRACK 4.0)

"Deflection Length" / Maxm. allowable local deflection


Joint No. denoting starting point for calculation of "Deflection Length" (See Note 1)


Joint No. denoting end point for calculation of "Deflection Length" (See Note 1)


Section 2B

2-44


Parameter

Name

Default

Value

Description

CAN 0 0 = deflection check based on the principle that maximum deflection occurs within the span between DJ1 and DJ2.

1 = deflection check based on the principle that maximum deflection is of the cantilever type (see note below)

ESTIFF 0.0 Clauses 4.8.3.3.1 and 4.8.3.3.2 0.0 = Fail ratio uses MIN of 4.8.3.3.1, 4.8.3.3.2. and

Annex I1 checks. 1.0 = Fail ratio uses MAX of 4.8.3.3.1, 4.8.3.3.2. and

Annex I1 checks. WELD 1.0 closed

2.0 open

Weld Type, see AISC steel design 1.0 = Closed sections. Welding on one side only (except

for webs of wide flange and tee sections) 2.0 = Open sections. Welding on both sides (except

pipes and tubes) TB 0.0 0.0 = Elastic stress analysis

1.0 = Plastic stress analysis PNL * 0.0 Transverse stiffener spacing („a‟ in Annex H1)

0.0 = Infinity Any other value used in the calculations.

SAME** 0.0 Controls the sections to try during a SELECT process.

0.0 = Try every section of the same type as original 1.0 = Try only those sections with a similar name as

original, e.g. if the original is an HEA 100, then only HEA sections will be selected, even if there are HEM‟s in the same table.

MX 1.0 Equivalent moment factor for major axis flexural buckling as defined in clause 4.8.3.3.4

MY 1.0 Equivalent moment factor for minor axis flexural buckling as defined in clause 4.8.3.3.4

MYX 1.0 Equivalent moment factor for minor axis lateral flexural buckling as defined in clause 4.8.3.3.4

MLT 1.0 Equivalent moment factor for lateral torsional buckling as defined in clause 4.8.3.3.4

SWAY none Specifies a load case number to provide the sway loading forces in clause 4.8.3.3.4 (See additional notes)

DMAX * 100.0cm Maximum allowable depth

Section 2B

2-45

Table 2B.1 British Steel Design – BS5950:2000 Parameters

Parameter

Name

Default

Value

Description

DMIN * 0.0cm Minimum allowable depth

RATIO 1.0 Permissible ratio of the actual capacities.

Note: Once a parameter is specified, its value stays at that specified

number till it is specified again. This is the way STAAD works for all

codes.

* current units must be considered. **For angles, if the original section is an equal angle, then the selected section will be an equal angle and vice versa for unequal angles. (note there was an NT parameter in STAAD.Pro 2005 build 1003 which is now automatically calculated during the design as it is load case dependant)

NOTES:

1) When performing the deflection check, the user can choose

between two methods. The first method, defined by a value 0 for

the CAN parameter, is based on the local displacement. Local

displacement is described in section 5.43 of this manual.

If the CAN parameter is set to 1, the check will be based on

cantilever style deflection. Let (DX1, DY1, DZ1) represent the

nodal displacements (in global axes) at the node defined by DJ1

(or in the absence of DJ1, the start node of the member). Similarly,

(DX2, DY2, DZ2) represent the deflection values at DJ2 or the end

node of the member.

Compute Delta = SQRT((DX2-DX1)**2 + (DY2-DY1)**2 +

(DZ2-DZ1)**2)

Compute Length = distance between DJ1 & DJ2 or, between start

node and end node, as the case may be.

Then, if CAN is specified a value 1, dff = L/Delta

Ratio due to deflection = DFF/dff


Section 2B

2-46

2) If CAN = 0, deflection length is defined as the length that is used

for calculation of local deflections within a member. It may be

noted that for most cases the “Deflection Length” will be equal to

the length of the member. However, in some situations, the

“Deflection Length” may be different. For example, refer to the

figure below where a beam has been modeled using four joints and

three members. The “Deflection Length” for a ll three members

will be equal to the total length of the beam in this case. The

parameters DJ1 and DJ2 should be used to model this situation.

Also the straight line joining DJ1 and DJ2 is used as the reference

line from which local deflections are measured. Thus, for all three

members here, DJ1 should be "1" and DJ2 should be "4".

3) If DJ1 and DJ2 are not used, "Deflection Length" will default to

the member length and local deflections will be measured from

original member line.

4) It is important to note that unless a DFF value is specified,

STAAD will not perform a deflection check. This is in accordance

with the fact that there is no default value for DFF (see Table 2.1).

5) The above parameters may be used in conjunction with other

available parameters for steel design.

2B.7 Design Operations

STAAD contains a broad set of facilities for the design of

structural members as individual components of an analysed

structure. The member design facilities provide the user with the

ability to carry out a number of different design operations. These

facilities may be used selectively in accordance with the

requirements of the design problem.

Section 2B

2-47

The operations to perform a design are:

Specify the load cases to be considered in the design; the

default is all load cases.

Specify design parameter values, if different from the default

values.

Specify whether to perform code checking or member selection

along with the list of members.

These operations may be repeated by the user any number of times

depending upon the design requirements.

2B.8 Code Checking

The purpose of code checking is to ascertain whether the provided


checked as per BS5950. Code checking is done using the forces

and moments at specific sections of the members. If no sections

are specified, the program uses the start and end forces for code

checking.

When code checking is selected, the program calculates and prints

whether the members have passed or failed the checks; the critical

condition of BS5950 code (like any of the BS5950 specifications

for compression, tension, shear, etc.); the value of the ratio of the

critical condition (overstressed for value more than 1.0 or any

other specified RATIO value); the governing load case, and the

location (distance from the start of the member of forces in the

member where the critical condition occurs).

Code checking can be done with any type of steel section listed in

Section 2B.4 of the STAAD Technical Reference Manual or any of

the user defined sections in section 5.19 with two exceptions;

GENERAL and ISECTION. In BS5950, these will not be considered

for design along with PRISMATIC sections, which are also not

acceptable.


Section 2B

2-48


STAAD is capable of performing design operations on specified

members. Once an analysis has been performed, the program can

select the most economical section, i.e. the lightest section, which

fulfills the code requirements for the specified member. The

section selected will be of the same type section as originally

designated for the member being designed. Member selection can

also be constrained by the parameters DMAX and DMIN, which

limits the maximum and minimum depth of the members.

Member selection can be performed with all the types of steel

sections with the same limitations as defined in section 2B.8 -

CODE CHECKING.

Selection of members, whose properties are originally input from a

user created table, will be limited to sections in the user table.

Member selection cannot be performed on members whose section

properties are input as prismatic or as above limitations for code

checking.

Section 2B

2-49


For code checking or member selection, the program produces the

results in a tabulated fashion. The items in the output table are

explained as follows:

a) MEMBER refers to the member number for which the

design is performed.

b) TABLE refers to steel section name, which has been

checked against the steel code or has been

selected.

c) RESULTS prints whether the member has PASSED or

FAILED. If the RESULT is FAIL, there will

be an asterisk (*) mark on front of the

member.

d) CRITICAL COND refers to the section of the BS5950 code

which governs the design.

e) RATIO prints the ratio of the actual stresses to

allowable stresses for the critical condition.

Normally a value of 1.0 or less will mean

the member has passed.

f) LOADING provides the load case number, which

governed the design.

g) FX, MY, and MZ provide the axial force, moment in local Y-

axis and the moment in local z-axis

respectively. Although STAAD does

consider all the member forces and moments

(except torsion) to perform design, only FX,

MY and MZ are printed since they are the

ones which are of interest, in most cases.


Section 2B

2-50

h) LOCATION specifies the actual distance from the start

of the member to the section where design

forces govern.

i) TRACK If the parameter TRACK is set to 1.0, the

program will block out part of the table and

will print the allowable bending capacities

in compression (MCY & MCZ) and reduced

moment capacities (MRY & MRZ),

allowable axial capacity in compression

(PC) and tension (PT) and shear capacity

(PV). TRACK 2.0 will produce the design

results as shown in section 2B.9.

2B.11 Plate Girders

Sections will be considered for the Plate Girder checks (BS 5950

Section 4.4) if d/t > 70 for „rolled sections‟ or d/t >62 for

„welded sections‟. The parameter SBLT should be used to identify

sections as rolled or welded; see the parameter list for more

information.

If the plate girder has intermediate stiffeners, the spacing is set

with the PNL parameter. These are then used to check against the

code clauses „4.4.3.2 - Minimum web thickness for serviceability‟

and „4.4.3.3 - Minimum web thickness to avoid compression

flange buckling‟. The following printout is then included if a

TRACK 2.0 output is selected:-

Shear Buckling check is required: Vb = 1070 kN : qw = 118 N/mm2

d = 900 mm : t = 10 mm : a = 200 mm : pyf = 275 N/mm2

BS-4.4.3.2 status = PASS : BS-4.4.3.3 status = PASS

The section is then checked for shear buckling resistance using

clause „4.4.5.2 - Simplified method‟ and the result is included in

the ratio checks.

Section 2B

2-51

2B.12 Composite Sections

Sections that have been defined as acting compositely with a

concrete flange either from a standard database section using the

CM option, or from a modified user WIDE FLANGE database with

the additional composite parameters, cannot be designed with

BS5950:2000.

2B.13 Design of Tapered Beams

Design Procedure

Sections will be checked as tapered members provided that are

defined either as a Tapered I section, e.g.

UNIT CM

MEMBER PROPERTY

1 TO 5 TAPERED 100 2.5 75 25 4 25 4

or from a USER table, e.g.

START USER TABLE

TABLE 1

UNIT CM

ISECTION

1000mm_TAPER

100 2.5 75 25 4 25 4 0 0 0

750mm_TAPER

75 2.5 50 25 4 25 4 0 0 0

END


Section 2B

2-52

The user must specify the effective length of unrestrained

compression flange using the parameter UNL.

The program compares the resistance of members with the applied

load effects, in accordance with BS 5950-1:2000. Code checking is

carried out for locations specified by the user via the SECTION

command or the BEAM parameter. The results are presented in a

form of a PASS/FAIL identifier and a RATIO of load effect to

resistance for each member checked. The user may choose the

degree of detail in the output data by setting the TRACK

parameter.

The beam is designed is designed as other wide flange beams apart

from the Lateral Torsional Buckling check which is replaced by

the Annex G.2.2. check.

Design Equations

A beam defined with tapered properties as defined above will be

checked as a regular wide flange (e.g. UB or UC), except that the

following is used in place of clause 4.3.6, the lateral torsional

buckling check.

Check Moment for Taper Members as per clause G.2.2

The following criterion is checked at each defined check position

in the length of the member defined by the BEAM parameter.

)/1( ccbixi PFMM

Where

Fc is the longitudinal compression at the check location ;

Mbi is the buckling resistance moment Mb from 4.3.6 for an

equivalent slenderness TB, see G.2.4.2, based on the

appropriate modulus S, Seff, Z or Zeff of the cross-section

at the point i considered;

Mxi is the moment about the major axis acting at the point i

considered;

Section 2B

2-53

Pc is the compression resistance from 4.7.4 for a slenderness

TC, see G.2.3, based on the properties of the minimum

depth of cross-section within the segment length Ly.

G.2.3 Slenderness TC

TC = y

In which:

5.0

22

2

)/(05.0)/2(1

)/2(1

xha

hay

s

s

= Ly/ry

Where

a is the distance between the reference axis and the axis of

restraint,

hs is the distance between the shear centers of the flanges;

Ly is the length of the segment;

ry is the radius of gyration for buckling about the minor axis;

x torsional index

G.2.4.2 Equivalent slenderness TB for Taper members

TB = cntt

In which for a two-flange haunch:

5.0

22 )/(05.0)/2(1

/4

xha

ha

s

s

t

Where

C is the taper factor, see G.2.5;


Section 2B

2-54

G.2.5 Taper factor

For an I-section with D ≥ 1.2B and x ≥ 20 the taper factor c

should be obtained as follows:

c = 1 +

3/2

min

max 19

3

D

D

x

Dmax is the maximum depth of cross-section within the

length Ly, see Figure G.3;

Dmin is the minimum depth of cross-section within the

length Ly, see Figure G.3;

x is the torsional index of the minimum depth cross -

section, see 4.3.6.8

Otherwise c is taken as 1.0

2-55


2B1.1 General

This code has been withdrawn by the British Standards, but has

been retained in STAAD.Pro for comparative purposes only.

The design philosophy embodied in BS5950 is built around the

concept of limit state design, used today in most modern steel

design codes. Structures are designed and proportioned taking into

consideration the limit states at which they become unfit for their

intended use. Two major categories of limit state are recognized -

serviceability and ultimate. The primary considerations in ultimate

limit state design are strength and stability while that in

serviceability limit state is deflection. Appropriate safety factors

are used so that the chances of limits being surpassed are

acceptably remote.

In the STAAD implementation of BS5950, members are

proportioned to resist the design loads without exceeding the limit

states of strength and stability. Accordingly, the most economic

section is selected on the basis of the least weight criteria. This

procedure is controlled by the designer in specification of

allowable member depths, desired sect ion type or other such

parameters. The code checking portion of the program checks that

code requirements for each selected section are met and identifies

the governing criteria.

The complete B.S.C. steel tables for both hot rolled and hollow

sections are built into the program for use in specifying member

properties as well as for the actual design process. See section

2B.4 for information regarding the referencing of these sections.

In addition to universal beams, columns, joists, piles, channels,

Section 2B1


Section 2B1

2-56

tees, composite sections, beams with cover plates, pipes, tubes and

angles, there is a provision for user provided tables.

2B1.2 Analysis Methodology









analysis results.

2B1.3 Member Property Specifications

For specification of member properties, the steel section li brary



steel table. Members properties may also be specified using the



2B1.4 Built-In Steel Section Library







Almost all BSI steel sections are available for input. A complete


may be obtained by using the tools of the graphical user interface.

Section 2B1

2-57

Following are the descriptions of different types of sections

available:

Universal Beams, Columns And Piles

All rolled universal beams, columns and pile sections are

available. The following examples illustrate the designation

scheme.

20 TO 30 TA ST UB305X165X54

33 36 TA ST UC356X406X287

100 102 106 TA ST UP305X305X186

Rolled Steel Joists

Joist sections may be specified as they are listed in BSI-80 with

the weight omitted. In those cases where two joists have the same

specifications but different weights, the lighter section should be

specified with an "A" at the end.

10 TO 20 TA ST JO152X127

1 2 TA ST JO127X114A

Channel Sections

All rolled steel channel sections from the BSI table have been

incorporated in STAAD. The designation is similar to that of the

joists. The same designation scheme as in BSI tables may be used

with the weight omitted.

10 TO 15 TA ST CH305X102

55 57 59 61 TA ST CH178X76

Double Channels

Back to back double channels, with or without spacing between them,

are available. The letter "D" in front of the section name will specify

a double channel, e.g. D CH102X51, D CH203X89 etc.


Section 2B1

2-58

51 52 53 TA D CH152X89

70 TO 80 TA D CH305X102 SP 5.

(specifies a double channel with a spacing of 5 length units)

Tee Sections


by referring to the universal beam shapes from which they are cut.

For example,

54 55 56 TA T UB254X102X22 (tee cut from

UB254X102X22)

Angles

All equal and unequal angles are available for input. Two types of

specifications may be used to describe an angle. The standard

angle section is specified as follows:

15 20 25 TA ST UA200X150X18

This specification may be used when the local STAAD z-axis

corresponds to the V-V axis specified in the steel tables. If the

local STAAD y-axis corresponds to the V-V axis in the tables,

type specification "RA" (reverse angle) may be used.

35 TO 45 TA RA UA200X150X18

Double Angles



of the angle size. In case of an equal angle, either LD or SD will


Section 2B1

2-59

14 TO 20 TA LD UA200X200X16 SP 1.5

23 27 TA SD UA80X60X6

"SP" denotes spacing between the individual angle

sections.


To designate circular hollow sections from BSI tables, use PIP


section in mm omitting the decimal section of the value provided for

diameter. The following example will illustrate the designation.

10 15 TA ST PIP213.2 (specifies a 21.3 mm dia. pipe with 3.2

mm wall thickness)



1 TO 9 TA ST PIPE OD 25.0 ID 20.0 (specifies a pipe with

outside dia. of 25 and inside dia. of 20 in current length

units)




Designation of tubes from the BSI steel table is illustrated below:

TUB 400 200 12.5

Tube symbol

Height (mm)

Thickness (mm)

Width (mm)


Section 2B1

2-60

Example: 15 TO 25 TA ST TUB160808.0



6 TA ST TUBE DT 8.0 WT 6.0 TH 0.5 is a tube that has a height

of 8, a width of 6, and a wall thickness of 0.5 length units.



2B1.5 Member Capacities

The basic measure of capacity of a beam is taken as the plastic

moment of the section. This is a significant departure from the

standard practice followed in BS449, in which the limiting

condition was attainment of yield stress at the extreme fibres of a

given section. With the introduction of the plastic moment as the

basic measure of capacity, careful consideration must be given to

the influence of local buckling on moment capacity. To assist this,

sections are classified as either plastic, compact, semi-compact or

slender, which governs the decision whether to use the plastic or

the elastic moment capacity. The section classification is a

function of the geometric properties of the section. STAAD is

capable of determining the section classification for both hot

rolled and built up sections. In addition, for slender sections,

BS5950 recommends the use of a 'stress reduction factor' to reduce

the design strength. This factor is again a function of the geometry

of the section and is automatically determined by STAAD for use

in the design process.

Axial Tension



member is calculated on the basis of the effective area as outlined

Section 2B1

2-61

in Section 4.6 of the code. STAAD calculates the tension capacity

of a given member per this procedure, based on a user supplied net

section factor (NSF-a default value of 1.0 is present but may be

altered by changing the input value - see Table 2B.1 ), proceeding

with member selection or code check accordingly. BS5950 does

not have any slenderness limitations for tension members.

Compression

Compression members must be designed so that the compression

resistance of the member is greater than the axial compressive

load. Compression resistance is determined according to the

compressive strength which is a function of the slenderness of the

gross section, the appropriate design strength and the relevant strut

characteristics. Strut characteristics take into account the

considerable influence residual rolling and welding stresses have

on column behaviour. Based on data collected from extensive

research, it has been determined that sections such as tubes with

low residual stresses and Universal Beams and Columns are of

intermediate performance. It has been found that I -shaped sections

are less sensitive to imperfections when constrained to fail about

an axis parallel to the flanges. These research observations are

incorporated in BS5950 through the use of four strut curves

together with a selection of tables to indicate which curve to use

for a particular case. Compression strength for a particular section

is calculated in STAAD according to the procedure outlined in

Appendix C of BS5950 where compression strength is seen to be a

function of the appropriate Robertson constant (representing Strut

Curve) corresponding Perry factor, limiting slenderness of the

member and appropriate design strength.

In addition to the compression resistance criteria, compression

members are required to satisfy slenderness limitations which are a

function of the nature of the use of the member (main load

resisting component, bracing member etc). In both the member

selection and the code checking process, STAAD immediately

does a slenderness check on appropriate members before

continuing with the other procedures for determining the adequacy

of a given member.


Section 2B1

2-62


In the case of axially loaded members with moments, the moment

capacity of the member must be calculated about both axes and all

axial forces must be taken into account . If the section is plastic or

compact, plastic moment capacities will constitute the basic

moment capacities subject to an elastic limitation. The purpose of

this elastic limitation is to prevent plasticity at working load. For

semi-compact or slender sections, the elastic moment is used. For

plastic or compact sections with high shear loads, the plastic

modulus has to be reduced to accommodate the shear loads. The

STAAD implementation of BS5950 incorporates the procedure

outlined in section 4.2.5 and 4.2.6 to calculate the appropriate

moment capacities of the section.

For members with axial tension and moment, the interaction

formula as outlined in section 4.8.2 is applied based on effective

tension capacity.

For members with axial compression and moment , two principal

interaction formulae must be satisfied - local capacity check

(4.8.3.2) and overall buckling check (section 4.8.3.3). Two types

of approach for the overall buckling check have been outlined in

BS5950 - the simplified approach and the more exact approach. As

noted in the code, in cases where neither the major axis nor the

minor axis moment approaches zero, the more exact approach may

be more conservative than the simplified approach. It has been

found, however, that this is not always the case and STAAD

therefore performs both checks, comparing the results in order that

the more appropriate criteria be used. Members subject to biaxial

moments in the absence of both tensile and compressive axial

forces are checked using the appropriate method described above

with all axial forces set to zero. STAAD also carries out cross

checks for compression only, which for compact/plastic sections

may be more critical. If this is the case, COMPRESSION will be

the critical condition reported despite the presen ce of moments.

Section 2B1

2-63

Shear Load

A member subjected to shear is considered adequate if the shear

capacity of the section is greater than the shear load on the

member. Shear capacity is calculated in STAAD using the

procedure outlined in section 4.2.3 and considering the appropriate

shear area for the section specified.


Since plastic moment capacity is the basic moment capacity used

in BS5950, members are likely to experience relatively large

deflections. This effect, coupled with la teral torsional buckling,

may result in severe serviceability limit state. Hence, lateral

torsional buckling must be considered carefully.

The procedure to check for lateral torsional buckling as outlined in

section 4.3 has been incorporated in the STAAD implementation

of BS5950. According to this procedure, for a member subjected to

moments about the major axis, the 'equivalent uniform moment' on

the section must be less than the lateral torsional buckling

resistance moment. For calculation of the bucklin g resistance

moment, the procedure outlined in Appendix B.2 has been

implemented for all sections with the exception of angles. In

Appendix B.2., the resistance moment is given as a function of the

elastic critical moment, Perry coefficient, and limiting equivalent

slenderness, which are calculated within the program; and the

equivalent moment factor, m, and slenderness correction factor, n,

which are determined as a function of the loading configuration

and the nature of the load ( stabilizing, destabilizing, etc ).

The user is allowed to control these values through the parameters

CMM & CMN. If CMM is set to -1, the program automatically

calculates the coefficient 'm'. Similarly parameter CMN may be

used for the calculation of coefficient 'n'. BS5950 recommends the

use of tables 15 & 16 for the calculation of coefficient 'n'. The

parameter CMN may be set to -1 or -2 to instruct the program to

obtain coefficient 'n' from table 15 or 16 respectively. If a positive

value is provided for either CMN or CMM, the program will use

this value directly in calculations. The default value for each of


Section 2B1

2-64

these parameters is 1.0 as shown in table 2B.1 of this document. It

may be noted that BS5950 recommends the use of either 'm' or 'n'

in lateral torsional buckling calculat ions. If both 'm' and 'n' are set

to values less than 1 in error, the program will always reset CMN

to 1 and over-ride the provided value. The following table

illustrates the use of parameters 'm' and 'n'.

PARAMETER VALUE STAAD ACTION

CMM ANY POSITIVE Direct use of this value in VALUE calculations. -1 Program calculates 'm' per BS5950 -2 Calculate „m‟ for both axes CMN ANY POSITIVE Direct use of this value in VALUE calculations. -1 Program calculates 'n' per BS5950 - Table 15 -2 Program calculates 'n' per BS5950 - Table 16

IMPORTANT NOTE:

Note that if negative value options are chosen, lateral restraints

should be modelled by nodes and the section command

incorporated to find Mo. Failure to use the SECTION 0.5

command will cause the program to reset CMN to 1.0 and over -

ride any value that may have been provided. In requesting 'n' to be

calculated by the program by using a negative CMN value, the

member properties must be British ( or British combined with user

table sections). If other profiles such as European are being used

then 'n' values are reset conservatively to 1.0 by the program. In

the case of angles, section 4.3.8 of the code is followed.

R. H. S Sections - Additional Provisions

Rectangular Hollow sections are treated in accordance with S.C.I.

recommendations in cases when the plastic axis is in the flange. In

such cases, the following expressions are used to calculate the

reduced plastic moduli:

Section 2B1

2-65

Srx = (A*A/4(B-t))(1-n) [ 2D(B-t)/A + n-1 ]

for n>= 2t(D-2t)/A

Sry = (A*A/4(D-t))(1-n) [ 2B(D-t)/A + n-1 ]

for n>= 2t(B-2t)/A

2B1.6 Design Parameters

Available design parameters to be used in conjunction with

BS5950 are listed in table 2B.1 along with their default values.

The following items should be noted with respect to their use.

1. (PY - STEEL DESIGN STRENGTH )

The design parameter PY should only be used when a uniform

design strength for an entire structure or a portion thereof is

required. Otherwise the value of PY will be set according to

the stipulations of BS5950 table 7 in which the design strength

is seen as a function of cross sectional thickness for a

particular steel grade and particular element considered.

Generally speaking this option is not required and the program

should be allowed to ascertain the appropriate value.

2. (UNL, LY and LZ - relevant EFFECTIVE LENGTHS)

The values supplied for UNL, LY and LZ should be real

numbers greater than zero in current units of length. They are

supplied along with or instead of UNF, KY KZ ( which are

factors, not lengths) to define lateral torsional buckling and

compression effective lengths respectively. Please note that

both UNL or UNF and LY or KY values are required even

though they are often the same values. The former relates to

compression flange restraint for lateral torsional buckling

while the latter is the unrestrained buckling length for

compression checks.

3. (CMN and CMM - Lateral torsional buckling coefficients)

As per section 2B.7 of this manual CMM and CMN should not

both be used in a given design. In such a case the program will

reset CMN to 1.0


Section 2B1

2-66

4. (TRACK - control of output formats )

When the TRACK parameter is set to 1.0 or 2.0, member

capacities will be printed in design related output ( code check

or member selection ) in kilonewtons per square metre. An

example of each follows.


--------------------------- ******************************



FX MY MZ LOCATION

=================================================================

1 ST UB686X254X170 PASS BS-4.8.3.2 0.036 3

86.72 C 0.00 -22.02 4.50

---------------------------------

Section 2B1

2-67


--------------------------- ******************************



FX MY MZ LOCATION

=================================================================

1 ST UB686X254X170 PASS BS-4.8.3.2 0.036 3

86.72 C 0.00 -22.02 4.50

CALCULATED CAPACITIES FOR MEMB 1 UNIT - kN,m SECTION CLASS 4

MCZ= 1141.9 MCY= 120.4 PC= 3451.5 PT= 5739.9 MB= 1084.1 PV= 1597.5

BUCKLING CO-EFFICIENTS m AND n : m = 1.000 n = 1.000

PZ= 5739.90 FX/PZ = 0.02 MRZ= 1141.9 MRY= 120.4

TRACK 2.0 OUTPUT STAAD CODE CHECKING - (BSI ) --------------------------- ****************************** ALL UNITS ARE - KNS METR (UNLESS OTHERWISE NOTED) MEMBER TABLE RESULT/ CRITICAL COND/ RATIO/ LOADING/ FX MY MZ LOCATION ================================================================= 1 ST UB686X254X170 PASS BS-4.8.3.2 0.036 3 86.72 C 0.00 -22.02 4.50 ================================================================= MATERIAL DATA

Grade of steel = 43 Modulus of elasticity = 205 kN/mm2 Design Strength (py) = 265 N/mm2 Reduced = 232N/mm2

SECTION PROPERTIES (units - cm)

Member Length = 450.00 Gross Area = 216.60 Net Area = 216.60

z-axis y-axis

Moment of inertia : 170147.000 6621.000 Plastic modulus : 5624.000 810.000 Elastic modulus : 4911.156 517.670 Shear Area : 109.122 100.470 Radius of gyration : 28.027 5.529 Effective Length : 450.000 450.000


Section 2B1

2-68

DESIGN DATA (units - kN,m) BS5950/1990

Section Class : SLENDER Squash Load : 5739.90 Axial force/Squash load : 0.015

z-axis y-axis

Slenderness ratio (KL/r) : 16.1 81.4 Compression Capacity : 5036.2 3451.5 Tension Capacity : 5739.9 5739.9 Moment Capacity : 1141.9 120.4 Reduced Moment Capacity : 1141.9 120.4 Shear Capacity : 1561.5 1597.5

BUCKLING CALCULATIONS (units - kN,m) Lateral Torsional Buckling Moment (MB = 1084.1) co-efficients m & n : m =1.00 n =1.00, Effective Length =4.500 CRITICAL LOADS FOR EACH CLAUSE CHECK (units- kN,m): CLAUSE RATIO LOAD FX VY VZ MZ MY BS-4.7 (C) 0.025 3 86.7 3.2 0.0 -22.0 0.0 BS-4.8.3.2 0.036 3 86.7 3.2 0.0 -22.0 0.0 BS-4.8.3.3.1 0.047 1 83.3 7.4 0.0 -27.6 0.0 BS-4.8.3.3.2 0.026 1 83.3 7.4 0.0 -27.6 0.0 BS-4.2.3-(Y) 0.005 1 83.3 7.4 0.0 -27.6 0.0 BS-4.3 (LTB) 0.020 4 -86.7 3.2 0.0 22.0 0.0

Torsion and deflections have not been considered in the design

5. ( LEG - table 24/28 BS5950 for fastner control )

The LEG parameter follows the requirements of BS5950 table

28. This table concerns the fastner restraint conditions for

angles, double angles, tee sections and channels for

slenderness. The following values are available:

Clause 4.7.10.2 (a) Single Angle, short leg 1.0

(b) Single Angle, short leg 0.0

(a) Single Angle, long leg 3.0

(b) Single Angle, long leg 2.0

Section 2B1

2-69

Clause 4.7.10.3 (a) Double angle, short leg 3.0

(b) Double angle, short leg 2.0

(c) Double angle, long leg 1.0

(d) Double angle, long leg 0.0

(a) Double angle, long leg 7.0

(b) Double angle, long leg 6.0

(c) Double angle, short leg 5.0

(d) Double angle, short leg 4.0

Clause 4.7.10.4 (a) Channels, 2 or more rows 1.0

(b) Channels, 1 row 0.0

Clause 4.7.10.5 (a) Tee sections, 2 or more rows 1.0

(b) Tee sections, 1 row 0.0

When defining member properties for single angles, the spec

(manual ref: 5.20.1) should be provided as RA and not ST. See fig

1.6 of the Technical Reference Manual.

Table 28 may be by-passed in favour of table 24 by using:

10 = Table 24 for equal angles or long legs of unequal

angles

11 = Table 24 for short legs of unequal angles

For single angles, LY and KY parameters should be provided

relative to the raa axis while LZ and KZ are related to rbb. Lvv

will be considered as the minimum of the KY*LY and KZ*LZ

values.

For double angles, the LVV parameter is available to comply with

note 5 table 28. In addition, if using double angles from user

tables, (Technical Reference Manual section 5.19) an eleventh

value, rvv, should be supplied at the end of the ten existing values

corresponding to the radius of gyration of the single angle making

up the pair.


Section 2B1

2-70

Table 2B1.1 - British Steel Design – BS5950:1990 - Parameters

Parameter

Name


KY 1.0 K factor value in local y - axis. Usually, this is the minor axis.

KZ 1.0 K factor value in local z - axis. Usually, this is the major axis.

LY * Member Length

Length in local y - axis (current units) to calculate (KY)(LY)/Ryy slenderness ratio.

LZ * Member Length

Length in local z - axis (current units) to calculate (KZ)(LZ)/Rzz slenderness ratio.

UNF 1.0 Factor applied to unsupported length for Lateral Torsional Buckling effective length per section 4.3.7.5 of BS5950.

UNL * Member Length

Unsupported Length for calculating Lateral Torsional Buckling resistance moment section 4.3.7.5 of BS5950.

PY * Set according to steel grade

(SGR)

Design Strength of steel


SGR 0.0 Steel Grade per BS4360 0.0 = Grade 43 1.0 = Grade 50 2.0 = Grade 55 3.0 = As per GB 1591 – 16 Mn

SBLT 0.0 0.0 = Rolled Section 1.0 = Built up Section

MAIN 1.0 As per BS5950 4.7.3 1.0 = Main structural member (180) 2.0 = Secondary member. (250) 3.0 = Bracing etc (350)

CMM ! 1.0 Coefficient m for lateral torsional buckling. (see section 2B.5)

CMN ! 1.0 Coefficient n for lateral torsional buckling. (see section 2B.5)

TRACK 0.0 0.0 = Suppress all member capacity info. 1.0 = Print all member capacities. 2.0 = Print detailed design sheet. 4.0 = Deflection Check (separate check to main select / check code)

Section 2B1

2-71


Parameter

Name


DMAX * 100.0cm Maximum allowable depth

DMIN * 0.0cm Minimum allowable depth

RATIO 1.0 Permissible ratio of the actual capacities.

BEAM 0.0 0.0 = Design only for end moments or those locations specified by the SECTION command.

1.0 = Calculate moments at 12th points along the member and use the maximum Mz value for design. Clause checks at one location

2.0 = Same as BEAM = 1.0 but additional checks are carried out for each end.

3.0 = Calculate moments at 12th points along the member. Clause checks at each location including the ends of the member.

CODE BS5950 Design Code to follow. See section 5.47.1 of the Technical Reference Manual.

LEG 0.0 Values range from 0 - 12. See section 2B.6.5 for details. The values correspond to table 24/28 of BS5950 for fastner conditions.

LVV * Maximum of Lyy and Lzz

(Lyy is a term used

by BS5950)

Used in conjunction with LEG for Lvv as per BS5950 table 28 for double angles, note 5.

CB 1.0 1.0 = BS5950 per clause B.2.5 (continuous) to calculate Mb.

2.0 = To calculate Mbs (simple) as per Clause 4.7.7 as opposed to Mb.

DFF None (Mandatory for

deflection check)






ESTIFF 0.0 Clauses 4.8.3.3.1 and 4.8.3.3.2 1.0 = Pass if member passes EITHER clause. 1.0 = Pass if member passes BOTH clauses.


Section 2B1

2-72


Parameter

Name


WELD 1.0 closed

2.0 open

Weld Type, see AISC steel design 1.0 = Welding on one side only (except for webs of wide

flange and tee sections) 2.0 = Welding on both sides (except pipes and tubes)

TB 0.0 2.0 = Elastic stress analysis 3.0 = Plastic stress analysis

PNL * 0.0 Transverse stiffener spacing („a‟ in Appendix H1) 0.0 = Infinity Any other value used in the calculations.

SAME ** 0.0 Controls the sections to try during a SELECT process.

0.0 = Try every section of the same type as original 1.0 = Try only those sections with a similar name as

original, e.g. if the original is an HEA 100, then only HEA sections will be selected, even if there are HEM‟s in the same table.



codes.

! CMN & CMM cannot both be provided. * current units must be considered.

**For angles, if the original section is an equal angle, then the selected section will be an equal angle and vice versa for unequal angles.

NOTES:

1) "Deflection Length" is defined as the length that is used for

calculation of local deflections within a member. It may be

noted that for most cases the "Deflection Length" will be equal

to the length of the member. However, in some situations, the

"Deflection Length" may be differen t. For example, refer to

the figure below where a beam has been modeled using four

joints and three members. Note that the "Deflection Length"

for all three members will be equal to the total length of the

beam in this case. The parameters DJ1 and DJ2 should be used

to model this situation. Also the straight line joining DJ1 and

DJ2 is used as the reference line from which local deflections

Section 2B1

2-73

are measured. Thus, for all three members here, DJ1 should be

"1" and DJ2 should be "4".

D = Maximum local deflection for members1, 2 and 3.

D

1

2 3

4

1

2 3

EXAMPLE : PARAMETERS

DFF 300. ALL

DJ1 1 ALL

DJ2 4 ALL

2) If DJ1 and DJ2 are not used, "Deflection Length" will default

to the member length and local deflections will be measured

from original member line.



2B1.7 Design Operations


structural members as individual components of an analysed




requirements of the design problem.

The operations to perform a design are:

Specify the load cases to be considered in the design.


values.

Specify whether to perform code checking or member selection

along with the list of members.




Section 2B1

2-74

2B1.8 Code Checking



checked as per BS5950. Code checking is done using the forces

and moments at specific sections of the members. If no sections

are specified, the program uses the start and end forces for code

checking.


whether the members have passed or failed the checks; the critical

condition of BS5950 code (like any of the BS5950 specifications

for compression, tension , shear, etc.); the value of the ratio of the

critical condition (overstressed for value more than 1.0 or any

other specified RATIO value); the governing load case, and the

location (distance from the start of the member of forces in the

member where the critical condition occurs).


Section 2B.4 of the STAAD Technical Reference Manual or any of

the user defined sections in section 5.19 with two exceptions ;

GENERAL and ISECTION. In BS5950, these will not be considered

for design along with PRISMATIC sections which are also not

acceptable.

2B1.9 Member Selection



select the most economical section, i.e. the lightest section, which




also be constrained by the parameters DMAX and DMIN which


Section 2B1

2-75

Member selection can be performed with all the types of steel

sections with the same limitations as defined in section 2B.8 -

CODE CHECKING.

Selection of members, whose properties are originally input from a

user created table, will be limited to sections in the user table.

Member selection can not be performed on members whose section

properties are input as prismatic or as above limitations for code

checking.

2B1.10 Tabulated Results of Steel Design




a) MEMBER refers to the member number for which the


b) TABLE refers to steel section name which has been

checked against the steel code or has been

selected.

c) RESULTS prints whether the member has PASSED or

FAILED. If the RESULT is FAIL, there will

be an asterisk (*) mark on front of the

member.

d) CRITICAL COND refers to the section of the BS5950 code


e) RATIO prints the ratio of the actual stresses to

allowable stresses for the critical condition.

Normally a value of 1.0 or less will mean

the member has passed.

f) LOADING provides the load case number which



Section 2B1

2-76

g) FX, MY, and MZ provide the axial force, moment in local Y-

axis and the moment in local z-axis

respectively. Although STAAD does

consider all the member forces and moments

(except torsion) to perform design, only FX,

MY and MZ are printed since they are the

ones which are of interest, in most cases.

h) LOCATION specifies the actual distance from the start

of the member to the section where design

forces govern.

i) TRACK If the parameter TRACK is set to 1.0, the

program will block out part of the table and

will print the allowable bending capacities

in compression (MCY & MCZ) and reduced

moment capacities (MRY & MRZ),

allowable axial capacity in compression

(PC) and tension (PT) and shear capacity

(PV). TRACK 2.0 will produce the design

results as shown in section 2B.9.

2B1.11 Plate Girders

Plate girders may be considered for design in BS5950. The "py"

used in the calculation of compressive strength is reduced by

20N/mm2 as per the code if parameter SBLT is set to 1.0. The code

requires that for d/t >63E, the interaction checks be modified in

order to check for shear buckling of the web. This is considered in

STAAD (versions 15.0 and over) following clause 4.4.4.2a and

4.4.4.3 of the code. The shear capacity is found from table 21 of

the code and used in clause 4.4.5.3. For plate girders, clauses

4.4.2.2a and 4.4.2.3a are also considered. In order to account for

these checks, the output has been modified to show these

variations from the more common critical checks. An example is

as follows, using TRACK 2.0, showing the bottom part of the

output having been modified as follows:

Section 2B1

2-77

BS5950 Table 7<note 2>: d/t > 63E Web Is Checked For Shear Buckling

d/t =101.7 qcr=191.9 N/mm2 d*t=14639 mm2 (4.4.5.3)Vcr= 2809.4 kN

Flange =COMPACT Pyf=344 N/mm2 4.4.2.2 a=PASS 4.4.2.3 a=PASS

Flange Ratio 4.4.4.2 (a) =0.20 L= 1 Web Ratio =0.05 L= 1

CRITICAL LOADS FOR EACH CLAUSE CHECK (units- kN,m):

CLAUSE RATIO LOAD FX VY VZ MZ MY

BS-4.8.3.3.2 0.177 1 0.0 -150.0 0.0 -1125.0 0.0

BS-4.2.3-(Y) 0.049 1 0.0 150.0 0.0 -1125.0 0.0

BS-4.3 (LTB) 0.151 1 0.0 -150.0 0.0 -1125.0 0.0

BS-4.4.5.3 0.053 1 0.0 150.0 0.0 -1125.0 0.0

BS-4.4.4.2 a 0.203 1 0.0 -150.0 0.0 -1125.0 0.0

2B1.12 Composite Sections

The definition of composite sections has been provided for in the

standard sections definition - section 5.20.1 of the Technical

Reference Manual. This is purely for analysis and for obtaining the

right section properties. It uses the American requirement of 18

times depth (CT) as the effective depth. For more control with

British sections two new options are available in user provided

tables.

1. WIDE FLANGE COMPOSITE:

Using the standard definition of I sections in WIDE FLANGE,

4 additional values can now be provided. The first is the width

of concrete to the left of centre of the steel web (b1). The

second is the concrete width to the right (b2). The third is the

concrete depth (d1) to be considered. The last is the modular

ratio. The above values are accepted in the program by adding

a '-' at the first position on the first line of data. The program

now awaits four extra values on line 2 as described above. If (-

) is provided on the second line the program requires another 2

breadths + 1 thickness for the bottom plate.


Section 2B1

2-78

2. ISECTION:

The same is true for ISECTION definition in user table.

3. EXAMPLE INPUT:

UNIT CM

WIDE FLANGE

C45752

-66.5 44.98 .76 15.24 1.09 21345 645 21.3 34.185 33.223

150 150 30 10

ISECTION

PG9144

-92.05 2.15 92.05 42.05 3.66 42.05 3.66 197.9 153.9 1730

40 40 12 1

The larger British sections have been coded as USER TABLES

under wide flange and are available on request to any existing

user. Please note however that composite design IS NOT available

in this portion of STAAD.

2-79

Design Per BS5400

2C.1 General Comments

BS5400 is an additional code available from Research Engineers.

It does not come as standard with British versions.

The British Standard, BS5400 adopts the limit state design

philosophy and is applicable to steel, concrete and composite

construction. The code is in 10 parts covering various aspects of

bridge design. The implementation of part 3, Code of practice for

design of steel bridges, in STAAD is restricted in its scope to

simply supported spans. It is assumed that the depth remains

constant and both construction and composite stages of steel I -

Sections can be checked. The following sections describe in more

detail features of the design process currently available in STAAD.

2C.2 Shape Limitations

The capacity of sections could be limited by local buckling if the

ratio of flange outstand to thickness is large. In order to preven t

this, the code sets limits to the ratio as per clause 9.3.2. In the

event of exceeding these limits, the design process will terminate

with reference to the clause.

Section 2C

Design Per BS5400

Section 2C

2-80

2C.3 Section Class

Sections are further defined as compact or non -compact. In the

case of compact sections, the full plastic moment capacity can be

attained. In the case of non compact sections, local buckling of

elements may occur prior to reaching the full moment capacity and

for this reason the extreme fibre stresses are limited to first yield.

In STAAD, section types are determined as per clause 9.3.7 and

the checks that follow will relate to the type of section considered.

2C.4 Moment Capacity

Lateral torsional buckling may occur if a member has unrestrained

elements in compression. The code deals with this effect by

limiting the compressive stress to a value depending on the

slenderness parameter which is a modified form of the ratio Le/Ry.

Le is the effective length governed by the provision of lateral

restraints satisfying the requirements of clause 9.12.1. Once the

allowable compressive stress is determined then the moment

capacity appropriate to the section type can be calculated. STAAD

takes the effective length as that provided by the user, defaulting

to the length of the member during construction stage and as zero,

assuming full restraint throughout, for the composite stage. The

program then proceeds to calculate the allowable compressive

stress based on appendix G7 from which the moment capacity is

then determined.

2C.5 Shear Capacity

The shear capacity, as outlined in clause is a function of the

limiting shear strength, l, which is dependant on the slenderness

ratio. STAAD follows the iterative procedure of appendix G8 to

determine the limiting shear strength of the web pan el. The shear

capacity is then calculated based on the formula given under

clause 9.9.2.2.

Section 2C

2-81

2C.6 Design Parameters

Available design parameters to be used in conjunction with BS5400

are listed in table 2C.1. Depending on the value assigned to the 'WET'

parameter, the users can determine the stage under consideration. For a

composite design check, taking into consideration the construction

stage, two separate analyses are required. In the first, member

properties are non-composite and the WET parameter is set to 1.0 . In

the second, member properties should be changed to composite and the

WET parameter set to 2.0. Member properties for composite or non -

composite sections should be specified from user provided tables

(refer to section 5.19 of the manual for specification of user tables).

Rolled sections, composite or non-composite, come under WIDE

FLANGE section-type and built-up sections under ISECTION. When

specifying composite properties the first parameter is assigned a

negative value and four additional parameters provided giving details

of the concrete section. See user table examples provided. Note: Once

a parameter is specified, its value stays at that specified number

till it is specified again. This is the way STAAD works for all codes.

Table 2C.1 - BS5400 Design Parameters

Parameter

Name


UNL* Member Length

Unsupported Length for calculating allowable compressive bending stress.

PY* Set according to Design Strength of steel SGR


SGR* 0.0 Steel Grade per BS4360

0.0 = Grade 43

1.0 = Grade 50

2.0 = Grade 55

SBLT 0.0 0.0 = Rolled Section

1.0 = Built up Section

MAIN 1.0 1.0 = Grade of concrete 30 N/mm2

Design Per BS5400

Section 2C

2-82

Table 2C.1 - BS5400 Design Parameters

Parameter

Name


2.0 = Grade of concrete 40 N/mm2

3.0 = Grade of concrete 50 N/mm2

WET 0.0 0.0 = Wet stage with no data saved for composite stage.

1.0 = Wet stage with data saved for composite stage.

2.0 = Composite and wet stage combined.

3.0 = Composite stage only.

TRACK 1.0 1.0 = Print all member capacities.

0.0 = suppress all member capacities.

BEAM 0.0 MUST BE CHANGED TO 1.0 FOR ALL RUNS

LY* Member Length

Length to calculate slenderness ratio for bending about Y-axis.

LZ* Member Length

Length to calculate slenderness ratio for bending about Z-axis.

KY 1.0 K value for bending about Y-axis. Usually this is minor axis.

KZ 1.0 K value for bending about Z-axis. Usually this is major axis.

STIFF 1.0 Factor of length for panel length in the shear calculation.

* Provided in current unit systems.

2C.7 Composite Sections

The definition of composite sections has been provided for in the

standard sections definition - section 5.20.1 of the Technical

Reference Manual. This is purely for analysis and for obtaining the

right section properties. It uses the American requirement of 18

times depth (CT) as the effective depth. For more control with

British sections two new options are available in user provided

tables.

Section 2C

2-83

1. WIDE FLANGE COMPOSITE:

Using the standard definition of I sections in WIDE FLANGE,

4 additional values can now be provided. The first is the width

of concrete to the left of centre of the steel web (b1). The

second is the concrete width to the right (b2). The third is the

concrete depth (d1) to be considered. The last is the modular

ratio. The above values are accepted in the program by adding

a '-' at the first position on the first line of data. The program

now awaits four extra values on line 2 as described above. If ( -

) is provided on the second line the program requires another 2

breadths + 1 thickness for the bottom plate.

2. ISECTION:

The same is true for ISECTION definition in user table.

3. EXAMPLE INPUT:

UNIT CM

WIDE FLANGE

C45752

-66.5 44.98 .76 15.24 1.09 21345 645 21.3 34.185 33.223

150 150 30 10

ISECTION

PG9144

-92.05 2.15 92.05 42.05 3.66 42.05 3.66 197.9 153.9 1730

40 40 12 1

The larger British sections have been coded as USER TABLES

under wide flange and are available on request to any existing

user. Please note however that composite design IS NOT available

in this portion of STAAD.

Design Per BS5400

Section 2C

2-84

2-85

Design Per BS8007

2D.1 General Comments

BS8007 is an additional code available from Research Engineers.

It does not come as standard with British versions.

STAAD has the capability of performing concrete slab design

according to BS8007. BS8007 provides recommendations for the

design of reinforced concrete structures containing aqueous

liquids. It is recommended that the design of the structure is

carried out according to BS8110, unless modified by the

recommendations given in BS8007.

Please use the following in conjunction with Section 2A of this

Manual - BS8110.

2D.2 Design Process

The design process is carried out in three stages.

1. Ultimate Limit States

The program is structured so that ultimate design is first carried

out in accordance with recommendations given in BS8110. All

active design load cases are considered in turn and a tabulated

output is printed showing possible reinforcement arrangements.

12, 16 and 20 mm bars are considered with possible spacings from

100,125,150,175 and 200 mm. Within these spacings, the layout

providing the closest area of steel is printed under each bar size.

Longitudinal and transverse moments together with critical load

Section 2D

Design Per BS8007

Section 2D

2-86

cases for both hogging and sagging moments are also printed.

Minimum reinforcement is in any case checked and provided in

each direction. WOOD & ARMER moments may also be included

in the design.

2. Serviceability Limit States

In the second stage, flexural crack widths under serviceability load

cases are calculated. The FIRST and EVERY OTHER OCCURING

design load case is considered as a serviceability load case and

crack widths are calculated based on bar sizes and spacings

proposed at the ultimate limit state check.

Crack widths due to longitudinal and transverse moments are

calculated directly under bars, midway between and at corners. A

tabulated output indicating critical serviceability load cases and

moments for top and bottom of the slab is then produced.

3. Thermal crack widths

Finally thermal, crack width calculations are carried out. Through

available parameters, the user is able to provide information on the

type of slab, temperature range and crack width limits.

Surface zone depths are determined based on the type of slab and

critical areas of reinforcements are calculated and printed in a

tabulated form.

Four bar sizes are considered and for each, max crack spacing,

Smax and crack widths are calculated for the critical

reinforcements and printed under each bar size.

Maximum bar spacing to limit crack widths to the user's limit is

also printed under each bar size.

Section 2D

2-87

2D.3 Design Parameters


perform and control the design to BS8007.

These parameters not only act as a method to input required data

for code calculations but give the Engineer control over the actual

design process. Default values of commonly used values for

conventional design practice have been chosen as the basis. Table

2D.1 contains a complete list of available parameters with their

default values.

2D.4 Structural Model

Structural slabs that are to be designed to BS8007 must be

modelled using finite elements. The manual provides information

on the sign convention used in the program for defining elements,

(See main manual section 2-6).

It is recommended to connect elements in such a way that the

positive local z axis points outwards away, from the centre of the

container. In this manner the "Top" of elements will consistently

fall on the outer surface and internal pressure loads will act in the

positive direction of the local z axis.

An example of a rectangular tank is provided to demonstrate the

above procedure.

Element properties are based on the thickness given under

ELEMENT PROPERTIES command. The following example

demonstrates the required input for a 300 mm slab modelled with

10 elements.

Design Per BS8007

Section 2D

2-88

UNIT MM

ELEMENT PROPERTIES

1 TO 10 THI 300.0

2D.5 Wood & Armer Moments

This is controlled by the SRA parameter. If the default value of

zero is used, the design will be based on the Mx and My moments

which are the direct results of STAAD analysis. The SRA

parameter (Set Reinforcement Angle) can be manipulated to

introduce WOOD & ARMER moments into the design replacing

the pure Mx, My moments. These new design moments allow the

Mxy moment to be considered when designing the section.

Orthogonal or skew reinforcement may be considered. SRA set to -

500 will assume an orthogonal layout. If however a skew is to be

considered, an angle is given in degrees, measured between the

local element x axis anti-clockwise (positive). The resulting Mx*

and My* moments are calculated and shown in the design format.

Section 2D

2-89

Table 2D.1 - BS8007 Design Parameters

Parameter

Name


FYMAIN * * 460 N/mm2 Yield for all reinforcing steel

FC * 30 N/mm2 Concrete grade.

CLEAR * 20 mm Distance from the outer surface to the edge of the bar. This is considered the same on both surfaces.

SRA 0.0 Orthogonal reinforcement layout without considering torsional moment Mxy - slabs on -500. orthogonal reinforcement layout with Mxy used to calculate WOOD &ARMER moments for design. A* Skew angle considered in WOOD & ARMER EQUATIONS. A* is any angle in degrees.

SCON 1 Parameter which indicates the type of slab ee. ground or suspended as defined in BS8007 1 = Suspended Slab 2 = Ground Slab

TEMP 30°C Temperature range to be considered in thermal crack width calculations

CRACK * 0.2 mm Limiting thermal crack width


number till it is specified again. This is the way STAAD works for

all codes.

* Provided in current unit systems

Design Per BS8007

Section 2D

2-90

2-91

Design Per British Cold Formed

Steel Code

2E.1 General

Provisions of BS 5950-5:1998, have been implemented. The

program allows design of single (non-composite) members in

tension, compression, bending, shear, as well as their

combinations. Cold work of forming strengthening effects have

been included as an option.

2E.2 Cross-Sectional Properties

The user specifies the geometry of the cross-section by selecting

one of the section shape designations from the Gross Section

Property Tables published in the “The Steel Construction

Institute”, (Design of Structures using Cold Formed Steel

Sections).

The Tables are currently available for the following shapes:

Channel with Lips

Channel without Lips

Z with Lips

Pipe

Tube

Shape assignment may be done using the member property pages

of the graphical user interface (GUI) or by specifying the section

designation symbol in the input file.

Section 2E

Design Per British Cold Formed Steel Code

Section 2E

2-92

The properties listed in the tables are gross section properties.

STAAD.Pro uses unreduced section properties in the structure

analysis stage. Both unreduced and effective section properties are

used in the design stage, as applicable.

2E.3 Design Procedure

The following two design modes are available:

1. Code Checking


load effects, in accordance with BS 5950-5:1998. Code checking is






parameter.

2. Member Selection

The user may request that the program search the cold formed steel

shapes database (BS standard sections) for alternative members

that pass the code check and meet the least weight criterion. In

addition, a minimum and/or maximum acceptable depth of the

member may be specified. The program will then evaluate all

database sections of the type initially specified (i.e., channel,

angle, etc.) and, if a suitable replacement is found, presents design

results for that section. If no section satisfying the depth

restrictions or lighter than the initial one can be found, the

program leaves the member unchanged, regardless of whether it

passes the code check or not.

Section 2E

2-93

The program calculates effective section properties in accordance

with Section 4 of the subject code. Cross-sectional properties and

overall slenderness of members are checked for compliance with

Clause 6.2.2, Maximum Effective Slenderness Ratio for

members in Compression

Clause 4.2, Maximum Flat Width Ratios for Elements in Compression

2E.4 Design Equations

Tensile Strength

The allowable tensile strength, as calculated in STAAD as per

BS5950-5, section 7 is described below.

The tensile strength, Pt of the member should be determined from

clause 7.2.1

yet pAP

Where

Ae is the net area An determined in accordance with cl.3.5.4

py is the design strength

Combined bending and tension

As per clause 7.3 of BS 5950-5:1998 members subjected to both

axial tension and bending should be proportioned such that the

following relationships are satisfied at the ultimate limit state

1cy

y

cz

z

t

t

M

M

M

M

P

F

And

cz

z

M

M 1


Section 2E

2-94

and

cy

y

M

M 1

Where

Ft is the applies tensile strength

Pt is the tensile capacity determined in accordance with

clause 7.2.1 of the subject code

Mz,My,Mcz,Mcy are as defined in clause 6.4.2 of the subject code

Compressive Strength

The allowable Compressive strength, as calculated in STAAD as

per BS5950-5, section 6 is described below

For sections symmetrical about both principal axes or closed

cross-sections which are not subjected to torsional flexural

buckling, the buckling resistance under axial load, Pc, may be

obtained from the following equation as per clause 6.2.3 of the

subject code

csE

csE

PP

PPPc

2

For Sections symmetrical about a single axis and which are not

subject to torsional flexural buckling, the buckling resistance

under axial load, Pc, may be obtained from the following equation

as per clause 6.2.4 of the subject code

)(

'scc

cc

cePM

PMP

Where the meanings of the symbols used are indicated in the

subject clauses.

Section 2E

2-95

Torsional flexural buckling

Design of the members which have at least one axis of symmetry,

and which are subject to torsional flexural buckling should be

done according to the stipulations of the clause 6.3.2 using

factored slenderness ratio LE/r in place of actual slenderness ratio

while reading Table 10 for the value of Compressive strength(p c).

Where

2/1

TF

E

P

P when PE > PTF

= 1 , otherwise

Where the meanings of the symbols used are indicated in the

subject clause.

Combined bending and compression

Members subjected to both axial compression and bending should

be checked for local capacity and overall buckling

Local capacity check as per clause 6.4.2 of the subject code

1cy

y

cz

z

cs

c

M

M

M

M

P

F

Overall buckling check as per clause 6.4.3 of the subject code

For Beams not subjected to lateral buckling, the following

relationship should be satisfied

1

11

Ey

ccyby

y

Ez

c

czbx

z

c

c

P

FMC

M

P

FMC

M

P

F

For Beams subjected to lateral buckling, the following relationship

should be satisfied


Section 2E

2-96

1

1

Ey

ccyby

y

b

z

c

c

P

FMC

M

M

M

P

F

Fc is the applied axial load

Pcs is the short strut capacity as per clause 6.2.3 Mz is the applied bending moment about z axis

My is the applied bending moment about y axis

Mcz is the moment capacity in bending about the local Z axis in

the absence of Fc and My, as per clause 5.2.2 and 5.6

Mcy is the moment capacity in bending about the local Y axis,

in the absence of Fc and Mz,as per clause 5.2.2 and 5.6

Mb is the lateral buckling resistance moment as per clause

5.6.2

PEz is the flexural buckling load in compression for bending

about the local Z axis

PEy is the flexural buckling load in compression for bending about the local Y axis

Cbz,Cby are taken as unity unless their values are specified by the

user

The Mcz, Mcy and Mb are calculated from clause numbers 5.2.2 and

5.6 in the manner described herein below.

Calculation of moment capacities

For restrained beams, the applied moment based on factored loads

should not be greater then the bending moment resistance of the

section, Mc

Mcz = Szz po

Mcy = Syy po

y

sw

o pY

t

Dp

2/1

2800019.013.1

Where

Mcz is the Moment resistance of the section in z axis

Mcz is the Moment resistance of the section in z axis

po is the limiting stress for bending elements under stress

gradient and should not greater then design strength py

Section 2E

2-97

For unrestrained beams the applied moment based on factored

loads should not be greater than the smaller of the bending

moment resistance of the section , Mc , and the buckling resistance

moment of the beam, Mb

Then buckling resistance moment, Mb, may be calculated as

follows

c

YEBB

YEb M

MM

MMM

2

Where

2

)1( EYB

MM

MY is the yield moment of the section , product of design

strength py and elastic modules of the gross section with

respect to the compression flange Zc

ME is the elastic lateral buckling resistance as per clause

5.6.2.2

is the Perry coefficient

Please refer clause numbers 5.2.2 and 5.6 of the subject code for a

detailed discussion regarding the parameters used in the

abovementioned equations.

Shear Strength

The maximum shear stress should not be greater then 0.7 py as

per clause 5.4.2

The average shear stress should not exceed the lesser of the shear

yield strength, pv or the shear buckling strength, qcr as stipulated in

clause 5.4.3 of the subject code.


Section 2E

2-98

The parameters are calculated as follows : -

pv = 0.6 py

2

2

/1000

mmND

tqcr

Pv = A*Min(pv,qcr)

Where

Pv is the shear capacity in N/mm^2

py is the design strength in N/mm^2

t is the web thickness in mm

D is the web depth in mm

Combined bending and Shear

For beam webs subjected to both bending and shear stresses the

member should be designed to satisfy the following relationship as

per the stipulations of clause 5.5.2 of the subject code

1

22

cv

v

M

M

P

F

Where

Fv is the shear force

M is the bending moment acting at the same section as Fv

Mc is the moment capacity determined in accordance with

5.2.2

The next table contains the input parameters for specifying values

of design variables and selection of design options.

Section 2E

2-99




BRITISH COLD FORMED STEEL DESIGN PARAMETERS

Parameter

Name

Default

Value Description

BEAM 1.0 When this parameter is set to 1.0 (default), the adequacy of the member is determined by checking a total of 13 equally spaced locations along the length of the member. If the BEAM value is 0.0, the 13 location check is not conducted, and instead, checking is done only at the locations specified by the SECTION command (See STAAD manual for details. For TRUSS members only start and end locations are designed.

CMZ 1.0 Coefficient of equivalent uniform bending Cb. See BS:5950-5:1998,5.6. Used for Combined axial load and bending design.

CMY 1.0 Coefficient of equivalent uniform bending Cb. See BS:5950-5:1998,5.6. Used for Combined axial load and bending design.

CWY 1.0 Specifies whether the cold work of forming strengthening effect should be included in resistance computation. See BS:5950-5:1998,3.4

Values: 0 – effect should not be included

1 – effect should be included

FLX 1 Specifies whether torsional-flexural buckling restraint is provided or is not necessary for the member. See BS:5950-5:1998, 5.6

Values:

0 – Section not subject to torsional flexural buckling 1 – Section subject to torsional flexural buckling

FU 430 MPa

Ultimate tensile strength of steel in current units.


Section 2E

2-100


Parameter

Name

Default

Value Description

FYLD 250 MPa

Yield strength of steel in current units.

KX 1.0 Effective length factor for torsional buckling. It is a fraction and is unit-less. Values can range from 0.01 (for a column completely prevented from buckling) to any user specified large value. It is used to compute the KL/R ratio for twisting for determining the capacity in axial compression.

KY 1.0 Effective length factor for overall buckling about the local Y-axis. It is a fraction and is unit-less. Values can range from 0.01 (for a column completely prevented from buckling) to any user specified large value. It is used to compute the KL/R ratio for determining the capacity in axial compression.

KZ 1.0 Effective length factor for overall buckling in the local Z-axis. It is a fraction and is unit-less. Values can range from 0.01 (for a member completely prevented from buckling) to any user specified large value. It is used to compute the KL/R ratio for determining the capacity in axial compression.

LX Member length

Unbraced length for twisting. It is input in the current units of length. Values can range from 0.01 (for a member completely prevented from torsional buckling) to any user specified large value. It is used to compute the KL/R ratio for twisting for determining the capacity in axial compression.

LY Member length

Effective length for overall buckling in the local Y-axis. It is input in the current units of length. Values can range from 0.01 (for a member completely prevented from buckling) to any user specified large value. It is used to compute the KL/R ratio for determining the capacity in axial compression.

Section 2E

2-101


Parameter

Name

Default

Value Description

LZ Member length

Effective length for overall buckling in the local Z-axis. It is input in the current units of length. Values can range from 0.01 (for a member completely prevented from buckling) to any user specified large value. It is used to compute the KL/R ratio for determining the capacity in axial compression.

MAIN 0 0 – Check slenderness ratio

0 – Do not check slenderness ratio

NSF 1.0 Net section factor for tension members DMAX

2540.0 cm. Maximum allowable depth. It is input in the current units of

length.

RATIO 1.0 Permissible ratio of actual to allowable stresses

TRACK 0 This parameter is used to control the level of detail in which the design output is reported in the output file. The allowable values are: 0 - Prints only the member number, section name, ratio,

and PASS/FAIL status. 1 - Prints the design summary in addition to that printed by

TRACK 1 2 - Prints member and material properties in addition to that

printed by TRACK 2.

2E.5 Verification Problem

In the next few pages are included a verification example for reference purposes.


Section 2E

2-102

Verification Problem-1

In this problem, we have assigned Channel sections with lips to

different members. Member numbers 28 to 31 have been assigned

section 230CLHS66X16,member numbers 3 TO 6 and 15 TO 19

have been assigned the section 230CLMIL70X30 and member

numbers 1, 2, 7 TO 14 have been assigned the section

170CLHS56X18. These members have been designed as per BS

5950 Part 5. Other sections have been assigned from the AISI

shapes database (American cold-formed steel) and designed in

accordance with that code.

The excerpts from the design output for member number 1 are

given herein below.

Section 2E

2-103

1) Bending Check

As per Clause 5.2.2.2 of BS 5950 –Part 5 the limiting compressive

stress(po ) for stiffened webs is given by the minimum of

y

sw

o pY

t

Dp

2/1

2800019.013.1

And

po = Py where Py = Min ( FYLD, 0.84XFU) = 361.2 N/mm2

So that

2.361280

212.279

8.1

1700019.013.1

2/1

op

= 332.727 N/mm2

The limiting compressive moments in local Y and Z axes will be given

by

Mcz = Szz po = 27632.4 X 332.727 = 9.19 X 106 N-mm

Mcy = Syy po = 27632.4 X 5427.50 = 3.46 X 106 N-mm

Maximum bending moment about local Z = 2159 N-m at node 7

Maximum bending moment about local Y = 19.755 N-m at node 7

Bending Ratio Z = 2.15 X106 / 9.19 X106 = 0.235 ……hence verified

Bending Ratio Y = 19755.3 / 3.46 X106 = 0.0057 ……hence verified

Buckling resistance moment Mb

As per section 5.6.2,

The buckling resistance moment

c

YEBB

YEb M

MM

MMM

2


Section 2E

2-104

Where,

The Yield moment(MY) of section is given by MY = Szz po = 9.19 X 10

6 N-mm

The elastic buckling resistance moment(ME ) as per clause 5.6.2.2

is calculated to be

4.649 X106 N-mm

And, 2

)1( EYB

MM

, so that

2

10649.4)0.01(1019.9 66 B

= 2.325 X 1010

Which gives

6621010

66

1019.910649.4)10325.2(10325.2

1019.910649.4

bM

= 9.98 X 106 N-mm

2) Compression Check

The Axial force induced in member# 1 is 3436.75 N

The elastic flexural buckling load PE = 1.185 X 106 N

The short strut capacity (Pcs ) is given by Aeff X py = 457.698 *

344 = 157448 N

Perry Coefficient () = 0.02074

[Pcs + (1+ ) EP

] 0.5 = 683512.45 N

Buckling resistance csE

csE

PP

PPPc

2 = 153782 N

Section 2E

2-105

For Channel section(being singly symmetric) as per clause 6.2.4

Buckling resistance )(

'scc

cc

cePM

PMP

Where

The limiting compressive moment(Mc) in the relevant direction =

9.19 X 106 N-mm,as calculated above

And the distance(es) of the geometric neutral axis of the gross

cross section and that of the effective cross section = 38.24 m

So that,

cP = 24.381537821019.9

1537821019.96

6

= 93788.7 N

Compression ratio =

0366.07.93788

75.3436

……hence verified

3) Axial Compression and Bending

Local capacity check as per clause 6.4.2

1cy

y

cz

z

cs

c

M

M

M

M

P

F

66

6

1081.1

3.19755

1019.9

1015.2

212.379698.457

75.3436

= 0.26

Over all buckling check : 6.4.3

1

11

Ey

ccyby

y

Ez

c

czbx

z

c

c

P

FMC

M

P

FMC

M

P

F

= 0.2773 ……hence verified


Section 2E

2-106

4) Shear Check as per clause 5.4.2 and 5.4.3

pv = 0.6 py = 0.6 379.212 = 227.52 N/mm2

2

2

/1000

mmND

tqcr

2

170

8.11000

crq

= 112.11 N/mm2 Pv = A*Min(pv,qcr) = 112.11 N/mm2

Shear resistance Y = 33579.4 N

Shear resistance Z = 21148.6 N

Shear Ratio Y =

1675.04.33579

72.5627


Shear Ratio Z =

0031.06.21148

114.67


5) Shear Check with Bending as per clause 5.5.2

Shear with bending on Z =

1

22

cz

z

v

v

M

M

P

F

=

2

6

62

1019.9

1015.2

4.33579

72.5627

=

0.08327 …… hence verified

Shear with bending on Y =

1

22

cy

y

v

v

M

M

P

F

=

2

6

2

1046.3

3.19755

6.21148

114.67

= 0.000….426 ……hence verified

Section 2E

2-107

Input File:

STAAD SPACE

SET ECHO OFF

INPUT WIDTH 79

UNIT FEET KIP

JOINT COORDINATES

1 0 5 0; 2 0 5 10; 3 10 5 0; 4 10 5 10; 5 5 5 0; 6 5 5 10; 7 0 5 2; 8 0 5 4;

9 0 5 6; 10 0 5 8; 11 10 5 2; 12 10 5 4; 13 10 5 6; 14 10 5 8; 15 5 5 2;

16 5 5 4; 17 5 5 6; 18 5 5 8; 19 10 0 0; 20 10 0 10; 21 0 0 10; 22 0 0 0;

MEMBER INCIDENCES

1 1 7; 2 3 11; 3 1 5; 4 2 6; 5 5 3; 6 6 4; 7 7 8; 8 8 9; 9 9 10; 10 10 2;

11 11 12; 12 12 13; 13 13 14; 14 14 4; 15 5 15; 16 15 16; 17 16 17; 18 17 18;

19 18 6; 20 7 15; 21 15 11; 22 8 16; 23 16 12; 24 9 17; 25 17 13; 26 10 18;

27 18 14; 28 1 22; 29 2 21; 30 3 19; 31 4 20; 32 1 21; 33 21 4; 34 4 19;

35 19 1; 36 2 20; 37 20 3; 38 3 22; 39 22 2;

MEMBER PROPERTY COLDFORMED AMERICAN

32 TO 39 TABLE ST 3LU3X060

20 TO 27 TABLE ST 3HU3X075

MEMBER PROPERTY COLDFORMED BRITISH

28 TO 31 TABLE ST 230CLHS66X16

3 TO 6 15 TO 19 TABLE ST 230CLMIL70X30

1 2 7 TO 14 TABLE ST 170CLHS56X18

UNIT MMS

PRINT MEMBER PROPERTIES LIST 32 20 28 3 1

SUPPORTS

19 TO 22 PINNED

UNIT FEET

DEFINE MATERIAL START

ISOTROPIC STEEL

E 4.176e+006

POISSON 0.3

DENSITY 0.489024

ALPHA 6.5e-006

DAMP 0.03

END DEFINE MATERIAL


Section 2E

2-108

CONSTANTS

BETA 90 MEMB 20 TO 27

MATERIAL STEEL MEMB 1 TO 39

MEMBER TENSION

32 TO 39

UNIT FEET KIP

LOAD 1 VERTICAL AND HORIZONTAL

MEMBER LOAD

3 TO 6 20 TO 27 UNI GY -0.3 0 5

JOINT LOAD

1 2 FX 0.6

2 4 FZ -0.6

PERFORM ANALYSIS PRINT STATICS CHECK

UNIT KGS CM

PRINT JOINT DISP LIST 1 4 16

PRINT SUPPORT REACTIONS

PRINT MEMBER FORCES LIST 3 24 28

UNIT KIP INCH

PARAMETER 1

CODE AISI

FYLD 55 ALL

CWY 1 ALL

BEAM 1 ALL

TRACK 2 ALL

CHECK CODE MEMB 20 21

PARAMETER 2

CODE BS5950 COLD

TRACK 2 MEMB 1 TO 19 28 TO 31

CHECK CODE MEMB 1 2

FINISH

Section 2E

2-109

Output File:

****************************************************

* *

* STAAD.Pro *

* Version Bld *

* Proprietary Program of *

* *

* Date= *

* Time= *

* *

* USER ID: *

****************************************************

1. STAAD SPACE

2. SET ECHO OFF

MEMBER PROPERTIES. UNIT - CM

-----------------

MEMB PROFILE AX/ IZ/ IY/ IX/

AY AZ SZ SY

32 ST 3LU3X060 2.26 21.81 5.17 0.02

1.51 1.51 4.05 1.93

20 ST 3HU3X075 4.91 63.15 40.66 0.06

1.24 2.40 10.63 9.59

28 ST 230CLHS66X16 8.78 663.30 42.82 0.18

5.40 2.94 60.93 9.29

3 ST 230CLMIL70X30

11.40 868.90 66.93 0.36

6.72 3.84 80.13 14.15

1 ST 170CLHS56X18 5.23 224.50 20.49 0.06

3.00 1.89 27.96 5.43

************ END OF DATA FROM INTERNAL STORAGE ************

**START ITERATION NO. 2

**NOTE-Tension/Compression converged after 2 iterations, Case= 1

STATIC LOAD/REACTION/EQUILIBRIUM SUMMARY FOR CASE NO. 1

VERTICAL AND HORIZONTAL

***TOTAL APPLIED LOAD ( KIP FEET ) SUMMARY (LOADING 1 )

SUMMATION FORCE-X = 1.20

SUMMATION FORCE-Y = -18.00

SUMMATION FORCE-Z = -1.20

SUMMATION OF MOMENTS AROUND THE ORIGIN-

MX= 84.00 MY= 12.00 MZ= -96.00

***TOTAL REACTION LOAD( KIP FEET ) SUMMARY (LOADING 1 )

SUMMATION FORCE-X = -1.20

SUMMATION FORCE-Y = 18.00

SUMMATION FORCE-Z = 1.20

SUMMATION OF MOMENTS AROUND THE ORIGIN-

MX= -84.00 MY= -12.00 MZ= 96.00

MAXIMUM DISPLACEMENTS ( INCH /RADIANS) (LOADING 1)

MAXIMUMS AT NODE

X = 1.56266E-02 1

Y = -4.80071E-01 16

Z = -1.74873E-02 4

RX= -8.28375E-03 6

RY= -2.10910E-05 14

RZ= -8.31623E-03 7



Section 2E

2-110

JOINT DISPLACEMENT (CM RADIANS) STRUCTURE TYPE = SPACE

------------------

JOINT LOAD X-TRANS Y-TRANS Z-TRANS X-ROTAN Y-ROTAN Z-ROTAN

1 1 0.0397 -0.0184 -0.0339 0.0074 0.0000 -0.0027

4 1 0.0305 -0.0185 -0.0444 -0.0074 0.0000 0.0025

16 1 0.0352 -1.2194 -0.0392 0.0025 0.0000 0.0000

************** END OF LATEST ANALYSIS RESULT **************

SUPPORT REACTIONS -UNIT KGS CM STRUCTURE TYPE = SPACE

-----------------

JOINT LOAD FORCE-X FORCE-Y FORCE-Z MOM-X MOM-Y MOM Z

19 1 -447.32 2312.64 85.08 0.00 0.00 0.00

20 1 -447.10 2041.85 186.39 0.00 0.00 0.00

21 1 174.26 1768.33 187.79 0.00 0.00 0.00

22 1 175.85 2041.85 85.05 0.00 0.00 0.00


MEMBER END FORCES STRUCTURE TYPE = SPACE

-----------------

ALL UNITS ARE -- KGS CM (LOCAL )

MEMBER LOAD JT AXIAL SHEAR-Y SHEAR-Z TORSION MOM-Y MOM-Z

3 1 1 669.42 1448.06 2.70 -1.68 -215.75 61582.12

5 -669.42 -767.67 -2.70 1.68 -196.10 107256.50

24 1 9 -0.63 -0.06 -285.30 -0.04 -0.08 1.04

17 0.63 0.06 -395.09 0.04 -8366.18 -9.62

28 1 1 2155.98 -404.11 -85.05 0.00 12961.01 -61586.40

22 -2155.98 404.11 85.05 0.00 0.00 0.00


STAAD.Pro CODE CHECKING - (AISI)

***********************

UNITS ARE: IN, KIP, KIP-IN, KSI

|-----------------------------------------------------------------------------|

| MEMBER# 20 SECTION: 3HU3X075 LEN: 60.00 GOV.LOC: 60.00 |

| STATUS: PASS RATIO = 0.285 GOV.MODE: Bend + Compress GOV.LOAD: 1 |

| |

| RESISTANCES: AX.TENS: 0.00 ECC.TENS: 0.00 COMPRESS: 7.51 |

| BEND. Z: 28.21 BEND. Y: 30.98 SHEAR Z: 11.76 SHEAR Y: 5.88 |

| |

| FYLD: 55.00 COLD WORK FYLD: 55.71 FU: 58.00 A: 0.76 AE: 0.76 |

| IZ: 1.5173E+00 IZE: 1.5173E+00 IY: 9.7684E-01 IYE: 9.7684E-01 |

| SZE_T: 6.4841E-01 SZE_C: 6.4841E-01 SYE_T: 5.8539E-01 SYE_C: 7.3374E-01 |

|-----------------------------------------------------------------------------|

|-----------------------------------------------------------------------------|

| MEMBER# 21 SECTION: 3HU3X075 LEN: 60.00 GOV.LOC: 0.00 |


| |

| RESISTANCES: AX.TENS: 0.00 ECC.TENS: 0.00 COMPRESS: 7.51 |

| BEND. Z: 28.21 BEND. Y: 30.98 SHEAR Z: 11.76 SHEAR Y: 5.88 |

| |

| FYLD: 55.00 COLD WORK FYLD: 55.71 FU: 58.00 A: 0.76 AE: 0.76 |

| IZ: 1.5173E+00 IZE: 1.5173E+00 IY: 9.7684E-01 IYE: 9.7684E-01 |

| SZE_T: 1.0115E+00 SZE_C: 1.0115E+00 SYE_T: 7.3374E-01 SYE_C: 5.8539E-01 |

|-----------------------------------------------------------------------------|

Section 2E

2-111

STAAD/Pro CODE CHECKING - (BS5950-5-v1.0)

***********************

UNITS : MM, KN, KNM, MPA

-------------------------------------------------------------------------------

| MEMBER# 1 SECTION: 170CLHS56X18 LEN: 609.60 LOCATION: 609.60 |


|------------------------------------------------ --------------------------|

MATERIAL DATA:

Yield strength of steel: 379.21 N/mm2

Ultimate tensile strength: 430.00 N/mm2

SECTION PROPERTIES:(units - cm)

Section Name: 170CLHS56X18

Member Length: 60.96

Gross Area(Ag): 5.46 Net Area (Ae): 4.58

z-z axis y-y axis

Moment of inertia (I) : 237.68 21.99

Moment of inertia (Ie): 236.04 19.44

Elastic modulus (Zet): 27.91 5.21

Elastic modulus (Zec): 27.63 10.41

DESIGN DATA:

z-z axis y-y axis

Tension Capacity (Pt): 0.00

Compression Capacity (Pc): 93.79

Moment Capacity (Mc): 9.19 3.46

Shear Capacity (Pc): 21.15 33.58

EACH CLAUSE CHECK UNDER CRITICAL LOAD :

CLAUSE COMBINATION RATIO

BS-6.3 Compression ratio - Axial 0.037

BS-6.4 Bend-Compression ratio 0.277

BS-5.1 Bending Ratio - Z 0.235

BS-5.1 Bending Ratio - Y 0.006

BS-5.1 Biaxial Bending Ratio 0.241

BS-5.4 Shear Ratio - Z 0.168

BS-5.4 Shear Ratio - Y 0.003

BS-5.5.2 Bending -Z & Shear - Y Ratio 0.083

BS-5.5.2 Bending -Y & Shear - Z Ratio 0.000


Section 2E

2-112

-------------------------------------------------------------------------------

| MEMBER# 2 SECTION: 170CLHS56X18 LEN: 609.60 LOCATION: 609.60 |


|------------------------------------------------ --------------------------|

MATERIAL DATA:

Yield strength of steel: 379.21 N/mm2

Ultimate tensile strength: 430.00 N/mm2

SECTION PROPERTIES:(units - cm)

Section Name: 170CLHS56X18

Member Length: 60.96

Gross Area(Ag): 5.46 Net Area (Ae): 4.58

z-z axis y-y axis

Moment of inertia (I) : 237.68 21.99

Moment of inertia (Ie): 236.04 21.99

Elastic modulus (Zet): 27.91 14.20

Elastic modulus (Zec): 27.63 5.43

DESIGN DATA:

z-z axis y-y axis

Tension Capacity (Pt): 0.00

Compression Capacity (Pc): 93.79

Moment Capacity (Mc): 9.19 1.81

Shear Capacity (Pc): 21.15 33.58

EACH CLAUSE CHECK UNDER CRITICAL LOAD :

CLAUSE COMBINATION RATIO

BS-6.3 Compression ratio - Axial 0.037

BS-6.4 Bend-Compression ratio 0.282

BS-5.1 Bending Ratio - Z 0.235

BS-5.1 Bending Ratio - Y 0.010

BS-5.1 Biaxial Bending Ratio 0.245

BS-5.4 Shear Ratio - Z 0.168

BS-5.4 Shear Ratio - Y 0.003

BS-5.5.2 Bending -Z & Shear - Y Ratio 0.083

BS-5.5.2 Bending -Y & Shear - Z Ratio 0.000

*********** END OF THE STAAD.Pro RUN ***********

Section 3

Canadian Codes

Aksf;ldkjasd

3-1

Concrete Design

Per CSA Standard A23.3-94


STAAD can perform design of concrete beams, columns and slabs

according to CSA STANDARD A23.3-94. Given the dimensions of

a section, STAAD will calculate the required reinforcement

necessary to resist the various input loads.



designed.

For Beams Prismatic (Rectangular, Square & Tee)


For Slabs 4-noded Plate Elements





Section 3A

Concrete Design Per CSA Standard A23.3-94

Section 3A

3-2

UNIT MM

MEMBER PROPERTIES

1 3 TO 7 9 PRISM YD 450. ZD 300.

11 14 PR YD 300.


(450mm depth and 300mm width) and the second set of members,


circular with a 300mm diameter.



slenderness effect in the analysis and design of concrete members.

The first method is equivalent to the procedure presented in CSA

STANDARD A23.3-94 Clause 10.13. STAAD accounts for the

secondary moments, due to axial loads and deflections, when the

PDELTA ANALYSIS command is used. After solving for the joint

displacements of the structure, the program calculates the

additional moments induced in the structure due to the P-Delta

effect. Therefore, by performing a PDELTA ANALYSIS, member

forces are calculated which will require no user modification

before beginning member design.

The second method by which STAAD allows the user to account

for the slenderness effect is through user suppl ied moment

magnification factors (see the parameter MMAG in Table 3A.1).

Here the user approximates the additional moment by supplying a

factor by which moments will be multiplied before beginning

member design. This second procedure allows slenderness to be

considered in accordance with Clause 10.14 of the code.

It should be noted that STAAD does not factor loads automatically

for concrete design. All the proper factored loads must be provided

by the user before the ANALYSIS specification.

Section 3A

3-3

While performing a PDELTA ANALYSIS, all load cases must be

defined as primary load cases. If the effects of separate load cases

are to be combined, it should be done either by using the REPEAT

LOAD command or by specifying the load information of these

individual loading cases under one single load case. Usage of the

LOAD COMBINATION command will yield incorrect results for

PDELTA ANALYSIS.



perform design per CSA STANDARD A23.3-94. These parameters

not only act as a method to input required data for code

calculations but give the engineer control over the actual design

process. Default values, which are commonly used numbers in

conventional design practice, have been used for simplici ty. Table

3A.1 contains a list of available parameters and their default

values. It is necessary to declare length and force units as

Millimeter and Newton before performing the concrete design.




Table 3A.1 - Canadian Concrete Design -CSA-A23.3-94 Parameters

Parameter Default Description

Name Value

FYMAIN 400N/mm2 Yield Stress for main reinforcing steel.

FYSEC 400 N/mm2 Yield Stress for secondary reinforcing steel.

FC 30 N/mm2 Specified compressive strength of concrete.

CLT 40mm Clear cover to reinforcing bar at top of cross section.

CLB 40mm Clear cover to reinforcing bar at bottom of cross section.

CLS 40mm Clear cover to reinforcing bar along the side of the cross section.

MINMAIN Number 10 bar Minimum main reinforcement bar size


Section 3A

3-4

Table 3A.1 - Canadian Concrete Design -CSA-A23.3-94 Parameters


Name Value

MINSEC Number 10 bar Minimum secondary (stirrup) reinforcement bar size.

MAXMAIN Number 55 bar Maximum main reinforcement bar size.

SFACE 0.0 Distance of face of support from start node of beam. Used for shear and torsion calculation.

EFACE 0.0 Face of Support Distance of face of support from end node of beam. Used for shear and torsion calculation. (Note: Both SFACE and EFACE are input as positive numbers).

REINF 0.0 Tied Column. A value of 1.0 will mean spiral.

TRACK 0.0 For TRACK = 0.0, Critical Moment will not be printed out with beam design report. For TRACK=1.0, moments will be printed.

MMAG 1.0 A factor by which the column design moments will be magnified.

NSECTION 12 Number of equally-spaced sections to be considered in finding critical moments for beam design.

WIDTH ZD Width of the concrete member. This value defaults to ZD as provided under MEMBER PROPERTIES.

DEPTH YD Depth of the concrete member. This value defaults to YD as provided under MEMBER PROPERTIES.

3A.6 Beam Design


forces, all active beam loadings are scanned to create moment and

shear envelopes, and locate critical sections. The total number of

sections considered is thirteen (start, end and 11 intermediate),

unless that number is redefined with the NSECTION parameter.

Design for Flexure

Design for flexure is performed per the rules of Chapter 2 of CSA

Standard A23.3-94. Maximum sagging (creating tensile stress at

the bottom face of the beam) and hogging (creating tensile stress

Section 3A

3-5

at the top face) moments are calculated for all active load cases at

each of the thirteen sections. Each of these sections are designed

to resist the critical sagging and hogging moments. Currently,

design of singly reinforced sections only is permitted. If the

section dimensions are inadequate as a singly reinforced section,

such a message will be printed in the output. Flexural design of

beams is performed in two passes. In the first pass, effective

depths of the sections are determined with the assumption of single

layer of assumed reinforcement and reinforcement requirements

are calculated. After the preliminary design, reinforcing bars are

chosen from the internal database in single or multiple layers. The

entire flexure design is performed again in a second pass taking

into account the changed effective depths of sections calculated on

the basis of reinforcement provided after the preliminary design.

Final provision of flexural reinforcements are made then. Efforts

have been made to meet the guideline for the curtailment of

reinforcements as per CSA Standard A23.3-94. Although exact

curtailment lengths are not mentioned explicitly in the design

output (which finally will be more or less guided by the detailer

taking into account other practical considerations), the user has the

choice of printing reinforcements provided by STAAD at 13

equally spaced sections from which the final detailed drawing can

be prepared.

The following annotations apply to the output for Beam Design.

1) LEVEL - Serial number of bar level which may

contain one or more bar group.

2) HEIGHT - Height of bar level from the bottom of

beam.

3) BAR INFOrmation - Reinforcement bar information

specifying number of bars and size.

4) FROM - Distance from the start of the beam to

the start of the rebar.

5) TO - Distance from the start of the beam to

the end of the rebar.


Section 3A

3-6

6) ANCHOR - States whether anchorage, either a hook

(STA,END) or continuation, is needed at start (STA)

or at the end (END) of the bar.

Design for Shear and Torsion

Design for shear and torsion is performed per the rules of Chapter 4

of CSA Standard A23.3-94. Shear reinforcement is calculated to resist

both shear forces and torsional moments. Shear design is performed at

the start and end sections. The location along the member span for

design is chosen as the effective depth + SFACE at the start, and

effective depth + EFACE at the end. The load case which gives rise to

the highest stirrup area for shear & torsion is chosen as the critical

one. The calculations are performed assuming 2-legged stirrups will

be provided. The additional longitudinal steel area r equired for

torsion is reported.

The stirrups are assumed to be U-shaped for beams with no

torsion, and closed hoops for beams subjected to torsion.


UNIT NEWTON MMS


CODE CANADA

FYMAIN 415 ALL

FYSEC 415 ALL

FC 35 ALL




DESIGN BEAM 2 TO 9

END CONCRETE DESIGN

Section 3A

3-7

3A.7 Column Design

Column design is performed per the rules of Chapters 7 & 8 of the

CSA Standard A23.3-94. Columns are designed for axial force and

biaxial moments at the ends. All active loadings are tested to

calculate reinforcement. The loading which produces maximum

reinforcement is called the critical load. Column design is done for

square, rectangular and circular sections. For rectangular and

square sections, the reinforcement is always assumed to be equally

distributed on each side. That means the total number of bars will

always be a multiple of four (4). This may cause slightly

conservative results in some cases.


UNIT NEWTON MMS


CODE CANADIAN

FYMAIN 415 ALL

FC 35 ALL




END CONCRETE DESIGN


To design a slab or wall, it must be modeled using finite elements.

The commands for specifying elements are in accordance with the

relevant sections of the Technical Reference Manual.

Elements are designed for the moments Mx and My using the same

principles as those for beams in flexure. The width of the beam is

assumed to be unity for this purpose. These moments are obtained

from the element force output (see the relevant sections of the


Section 3A

3-8

Technical Reference Manual). The reinforcement required to resist

Mx moment is denoted as longitudinal reinforcement and the

reinforcement required to resist My moment is denoted as

transverse reinforcement. The effective depth is calculated

assuming #10 bars are provided. The parameters FYMAIN, FC,

CLT and CLB listed in Table 3A.1 are relevant to slab design.

Other parameters mentioned in Table 3A.1 are not applicable to

slab design. The output consists only of area of steel required.

Actual bar arrangement is not calculated because an element most

likely represents just a fraction of the total slab area.

LONG.

TRANS.

X

Y

Z

M

MM

Mx

y

x

y


UNIT NEWTON MMS


CODE CANADA

FYMAIN 415 ALL

FC 35 ALL

CLB 40 ALL


END CONCRETE DESIGN

3-9

Steel Design Per CSA Standard

CAN/CSA-S16-01

3B.1 General Comments

The design of structural steel members in accordance with the

specification CAN/CSA S16-01 Limit States Design of Steel

Structures is now implemented. This code supercedes the previous

edition of the code CAN/CSA – S16.1-94.




















criteria.

Section 3B

Steel Design Per CSA Standard CAN/CSA-S16-01

Section 3B

3-10


implementation of CAN/CSA-S16-01. A detailed description of the

design process along with its underlying concepts and assumptions

is available in the specification document.










analysis results.















Section 3B

3-11

Almost all Canadian steel sections are available for input. A

complete listing of the sections available in the built -in steel


user interface.

Following is the description of the different types of sections

available:

Welded Wide Flanges (WW shapes)

Welded wide flange shapes listed in the CSA steel tables can be

designated using the same scheme used by CSA. The following

example illustrates the specification of welded wide flange shapes.

100 TO 150 TA ST WW400X444

34 35 TA ST WW900X347

Wide Flanges (W shapes)

Designation of wide flanges in STAAD is the same as that in CSA

tables. For example,

10 TO 75 95 TO 105 TA ST W460X106

100 TO 200 TA ST W610X101

S, M, HP shapes

In addition to welded wide flanges and regular wide flanges, other

I shaped sections like S, M and HP shapes are also available. The

designation scheme is identical to that listed in the CSA tables.

While specifying the sections, it should be remembered that the

portion after the decimal point should be omitted. Thus,

M310X17.6 should be specified as M310X17 and S180X22.8

should be specified as S180X22. Examples illustrating

specifications of these shapes are provided below.


Section 3B

3-12

10 TO 20 BY 2 TA ST S510X98

45 TO 55 TA ST M150X6

88 90 96 TA ST HP310X79

Channel Sections (C & MC shapes)

C and MC shapes are designated as shown in the following

example. As in S, M and HP sections, the portion after the decimal

point must be omitted in section designations. Thus, MC250X42.4

should be designated as MC250X42.

55 TO 90 TA ST C250X30

30 TO 45 TA ST MC200X33

Double Channels

Back to back double channels, with or without spacing between

them, are specified by preceding the section designation by the

letter D. For example, a back to back double channel section

C200X28 without any spacing in between should be specified as:

100 TO 120 TA D C200X28

If a spacing of 2.5 length units is used, the specification should be

as follows:

100 TO 120 TA D C200X28 SP 2.5

Note that the specification SP after the section designation is used

for providing the spacing. The spacing should always be provided

in the current length unit.

Section 3B

3-13

Angles

To specify angles, the angle name is preceded by the letter L.

Thus, a 200X200 angle with a 25mm thickness is designated as

L200X200X25. The following examples illustrate angle

specifications.

75 TO 95 TA ST L100X100X8

33 34 35 TA ST L200X100X20

Note that the above specification is for “standard” angles. In this

specification, the local z-axis (see Fig. 2.6 in the Technical

Reference Manual) corresponds to the Y‟-Y‟ axis shown in the

CSA table. Another common practice of specifying angles assumes

the local y-axis to correspond to the Y‟-Y‟ axis. To specify angles

in accordance with this convention, the reverse angle designation

facility has been provided. A reverse angle may be specified by

substituting the word ST with the word RA. Refer to the following

example for details.

10 TO 15 TA RA L55X35X4

The local axis systems for STANDARD and REVERSE angles is

shown in Fig. 2.6 of the STAAD Technical Reference manual.

Double Angles

To specify double angles, the specification ST should be

substituted with LD (for long leg back to back) or SD (short leg

back to back). For equal angles, either SD or LD will serve the

purpose. Spacing between angles may be provided by using the

word SP followed by the value of spacing (in current length unit)

after section designation.

25 35 45 TA LD L150X100X16

80 TO 90 TA SD L125X75X6 SP 2.5


Section 3B

3-14

The second example above describes a double angle section

consisting of 125X75X6 angles with a spacing of 2.5 length units.

Tees

Tee sections obtained by cutting W sections may be specified by

using the T specification instead of ST before the name of the W

shape. For example:

100 TO 120 TA T W200X42

will describe a T section cut from a W200X42 section.

Rectangular Hollow Sections

These sections may be specified in two possible ways. Those

sections listed in the CSA tables may be specified as follows.

55 TO 75 TA ST TUB80X60X4

Tube Symbol Thickness (in) X16

Width (in.) X10

TUB 80 X 60 X 4

Height (in) X 10

In addition, any tube section may be specified by using the DT(for

depth), WT(for width), and TH(for thickness) specifications.

Section 3B

3-15

For example:

100 TO 200 TA ST TUBE DT 8.0 WT 6.0 TH 0.5

will describe a tube with a depth of 8 in., width of 6 in. and a wall

thickness of 0.5 inches. Note that the values of depth, width and

thickness must be provided in current length unit.

Circular Hollow Sections

Sections listed in the CSA tables may be provided as follows:

15 TO 25 TA ST PIP33X2.5

Pipe Symbol Thickness (mm)

Diameter (mm)

PIP 33 X 2.5

(Upto first decimal place only)

without decimal point

In addition to sections listed in the CSA tables, circular hollow

sections may be specified by using the OD (outside diameter) and

ID (inside diameter) specifications. For example:


will describe a pipe with an outside diameter of 10 length units

and inside diameter of 9.0 length units. Note that the values of

outside and inside diameters must be provided in terms of current

length unit.


Section 3B

3-16

Sample input file to demonstrate usage of Canadian shapes

STAAD SPACE

UNIT METER KNS

JOINT COORD

1 0 0 0 17 160 0 0

MEMBER INCIDENCES

1 1 2 16

UNIT CM

MEMBER PROPERTIES CANADIAN

* W SHAPES

1 TA ST W250X18

* WW SHAPES

2 TA ST WW700X185

* S SHAPES

3 TA ST S200X27

* M SHAPES

4 TA ST M130X28

* HP SHAPES

5 TA ST HP310X132

* MC CHANNELS

6 TA ST MC150X17

* C CHANNELS

7 TA ST C180X18

* DOUBLE CHANNELS

8 TA D C250X37 SP 1.0

* ANGLES

9 TA ST L55X35X5

* REVERSE ANGLES

10 TA RA L90X75X5

* DOUBLE ANGLES, LONG LEG BACK TO BACK

11 TA LD L100X90X6 SP 2.0

* DOUBLE ANGLES, SHORT LEG BACK TO BACK

12 TA SD L125X75X6 SP 2.5

* TUBES

13 TA ST TUB120807

Section 3B

3-17

* TUBES


* PIPES

15 TA ST PIP273X6.3

* PIPES


PRINT MEMBER PROPERTIES

FINISH


The CSA specification allows inelastic deformation of section


Steel sections are classified as plastic (Class 1), compact (Class 2),

non compact (Class 3) or slender element (Class 4) sections

depending upon their local buckling characteristics (See Clause

11.2 and Table 1 of CAN/CSA-S16-01). This classification is a

function of the geometric properties of the section. The design

procedures are different depending on the section class. STAAD

determines the section classification for the standard shapes and

user specified shapes. Design is performed for sections that fall

into the category of Class 1,2 or 3 sections only. Class 4 sect ions

are not designed by STAAD.


The member resistances are calculated in STAAD according to the

procedures outlined in section 13 of the specification. These

depend on several factors such as members unsupported lengths,

cross-sectional properties, slenderness factors, unsupported width

to thickness ratios and so on. Note that the program automatically

takes into consideration appropriate resistance factors to calculate

member resistances. Explained here is the procedure adopted in

STAAD for calculating the member resistances.


Section 3B

3-18

Axial Tension

The criteria governing the capacity of tension members is based on

two limit states. The limit state of yielding in the gross section is



minimum effective net area. The net section area may be specified

by the user through the use of the parameter NSF (see Table 3B.1).


these two limits states per Cl.13.2 of CAN/CSA-S16-01.

Parameters FYLD, FU and NSF are applicable for these

calculations.

Axial Compression

The compressive resistance of columns is determined based on

Clause 13.3 of the code. The equations presented in th is section of

the code assume that the compressive resistance is a function of

the compressive strength of the gross section (Gross section Area

times the Yield Strength) as well as the slenderness factor (KL/r

ratios). The effective length for the calcula tion of compression

resistance may be provided through the use of the parameters KX,

KY, KZ, LX, LY and LZ (see Table 3B.1). Some of the aspects of

the axial compression capacity calculations are :

1) For frame members not subjected to any bending, and for t russ

members, the axial compression capacity in general column

flexural buckling is calculated from Cl.13.3.1 using the

slenderness ratios for the local Y-Y and Z-Z axis. The

parameters KY, LY, KZ and LZ are applicable for this.

2) For single angles, which are frame members not subjected to

any bending or truss members, the axial compression capacity

in general column flexural buckling and local buckling of thin

legs is calculated using the rules of the AISC - LRFD code, 2nd

ed., 1994. The reason for this is that the Canadian code doesn‟t

provide any clear guidelines for calculating this value. The


3) The axial compression capacity is also calculated by taking

flexural-torsional buckling into account. The rules of

Appendix D, page 1-109 of CAN/CSA-S16-01are used for this

Section 3B

3-19

purpose. Parameters KX and LX may be used to provide the

effective length factor and effective length value for flexural -

torsional buckling. Flexural-torsional buckling capacity is

computed for single channels, single angles, Tees and Double

angles.

4) The variable “n” in Cl.13.3.1 is assumed as 2.24 for WWF

shapes and 1.34 for all other shapes.

5) While computing the general column flexural buckling

capacity of sections with axial compression + bendin g, the

special provisions of 13.8.1(a), 13.8.1(b) and 13.8.1(c) are

applied. For example, Lambda = 0 for 13.8.1(a), K=1 for

13.8.1(b), etc.)

Bending

The laterally unsupported length of the compression flange for the

purpose of computing the factored moment resistance is specified

in STAAD with the help of the parameter UNL. If UNL is less

than one tenth the member length (member length is the distance

between the joints of the member), the member is treated as being

continuously laterally supported. In this case, the moment

resistance is computed from Clause 13.5 of the code. If UNL is

greater than or equal to one tenth the member length, its value is

used as the laterally unsupported length. The equations of Clause

13.6 of the code are used to arrive at the moment of resistance of

laterally unsupported members. Some of the aspects of the bending

capacity calculations are :

1) The weak axis bending capacity of all sections except single

angles is calculated as

For Class 1 & 2 sections, Phi*Py*Fy

For Class 3 sections, Phi*Sy*Fy

where Phi = Resistance factor = 0.9

Py = Plastic section modulus about the local Y axis

Sy = Elastic section modulus about the local Y axis

Fy = Yield stress of steel


Section 3B

3-20

2) For single angles, the bending capacities are calculated for the

principal axes. The specifications of Section 5, page 6-283 of

AISC-LRFD 1994, 2nd

ed., are used for this purpose because

the Canadian code doesn‟t provide any clear guidelines for

calculating this value.

3) For calculating the bending capacity about the Z-Z axis of

singly symmetric shapes such as Tees and Double angles,

CAN/CSA-S16-01 stipulates in Clause 13.6(d), page 1-31, that

a rational method, such as that given in SSRC‟s Guide to

Stability Design Criteria of Metal Structures, be used. Instead,

STAAD uses the rules of Section 2c, page 6-55 of AISC-LRFD

1994, 2nd ed.

Axial compression and bending



interaction equations. In these equations, the additional bending

caused by the action of the axial load is accounted for by using

amplification factors. Clause 13.8 of the code provides the

equations for this purpose. If the summation of the left hand side

of these equations exceed 1.0 or the allowable value provided

using the RATIO parameter (see Table 3B.1), the member is

considered to have FAILed under the loading condition.

Axial tension and bending

Members subjected to axial tension and bending are also designed

using interaction equations. Clause 13.9 of the code is used to

perform these checks. The actual RATIO is determined as the

value of the left hand side of the critical equation.

Shear

The shear resistance of the cross section is determined using the

equations of Clause 13.4 of the code. Once this is obtained, the

ratio of the shear force acting on the cross section to the shear

resistance of the section is calculated. If any of the ratios (for both

local Y & Z axes) exceed 1.0 or the allowable value provided

using the RATIO parameter (see Table 3B.1), the section is

Section 3B

3-21

considered to have failed under shear. The code also requires that

the slenderness ratio of the web be within a certain limit (See

Cl.13.4.1.3, page 1-29 of CAN/CSA-S16-01). Checks for safety in

shear are performed only if this value is within the allowable limit.

Users may by-pass this limitation by specifying a value of 2.0 for

the MAIN parameter.






specific needs.








Canadian Steel Design Parameters


Name Value

KT 1.0 K value for flexural torsional buckling.

KY 1.0 K value for general column flexural buckling about the local Y-axis. Used to calculate slenderness ratio.

KZ 1.0 K value for general column flexural buckling about the local Z-axis. Used to calculate slenderness ratio.

LT Member Length Length for flexural torsional buckling.

LY Member Length Length for general column flexural buckling about the local Y-axis. Used to calculate slenderness ratio.


Section 3B

3-22



Name Value

LZ Member Length Length for general column flexural buckling about the local Z-axis. Used to calculate slenderness ratio.


FU 345.0 MPa Ultimate strength of steel.


UNT Member Length Unsupported length in bending compression of the top flange for calculating moment resistance.

UNB Member Length Unsupported length in bending compression of the bottom flange for calculating moment resistance.

MAIN 0.0 0.0 = Check slenderness ratio against the limits. 1.1 = Suppress the slenderness ratio check.

2.0 = Check slenderness ratio only for column buckling, not for web (See Section 3B.6, Shear)

CB 1.0 Greater than 0.0 and less than 2.5 : Value of Omega_2 (Cl.13.6) to be used for calculation.

Equal to 0.0 : Calculate Omega_2

CMY 1.0 1.0 = Do not calculate Omega-1 for local Y axis. 2.0 = Calculate Omega-1 for local Y axis. Used in Cl.13.8.4 of code

CMZ 1.0 1.0 = Do not calculate Omega-1 for local Z axis. 2.0 = Calculate Omega-1 for local Z axis. Used in Cl.13.8.4 of code

TRACK 0.0 0.0 = Report only minimum design results.

1.0 = Report design strengths also.

2.0 = Provide full details of design.

DMAX 45.0 in. Maximum allowable depth (Applicable for member selection)

DMIN 0.0 in. Minimum required depth (Applicable for member selection)

RATIO 1.0 Permissible ratio of actual load effect to the design strength.

Section 3B

3-23



Name Value

BEAM 0.0 0.0 = design only for end moments and those at locations specified by SECTION command.

1.0 = Perform design for moments at twelfth points along the beam.

DFF None(Mandatory for deflection

check)

“Deflection Length”/Maxm. Allowable local deflection.


Joint No. denoting start point for calculation of “deflection length”


Joint No. denoting end point for calculation of “deflection length”

3B.8 Code Checking



checked as per the CAN/CSA-S16-01 requirements.

Code checking is done using forces and moments at specified

sections of the members. If the BEAM parameter for a member is

set to 1, moments are calculated at every twelfth point along the

beam. When no sections are specified and the BEAM parameter is

set to zero (default), design will be based on member start and end

forces only. The code checking output labels the members as

PASSed or FAILed. In addition, the critical condition, governing

load case, location (distance from the start joint) and magnitudes

of the governing forces and moments are also printed. The extent

of detail of the output can be controlled by using the TRACK

parameter.


Section 3B

3-24

Example of commands for CODE CHECKING:

UNIT NEWTON METER

PARAMETER

FYLD 330E6 MEMB 3 4

NSF 0.85 ALL

KY 1.2 MEMB 3 4

UNL 15 MEMB 3 4

RATIO 0.9 ALL

CHECK CODE MEMB 3 4






For example, a member specified initially as a chann el will have a



the user table. Member selection cannot be performed on TUBES,

PIPES or members listed as PRISMATIC.

Section 3B

3-25

Example of commands for MEMBER SELECTION:

UNIT NEWTON METER

PARAMETER

FYLD 330E6 MEMB 3 4

NSF 0.85 ALL

KY 1.2 MEMB 3 4

UNL 15 MEMB 3 4

RATIO 0.9 ALL

SELECT MEMB 3 4




the CAN/CSA-S16-01 specification which governed the design.

If the TRACK parameter is set to 1.0, factored member resistances

will be printed. Following is a description of some of the items

printed.

CR = Factored compressive resistance

TR = Factored tensile resistance

VR = Factored shear resistance

MRZ = Factored moment resistance (about z-axis)

MRY = Factored moment resistance (about y-axis)

Further details can be obtained by setting TRACK to 2.0.

CR1 = CAPACITY (Cr) PER 13.8.2(a)

CR2 = CAPACITY (Cr) PER 13.8.2(b)

CRZ = SEE 13.8.2(b) for uniaxial bending (called CRX in that

Clause)

CTORFLX = Capacity in accordance with 13.8.2(c)


Section 3B

3-26

3B.11 Verification Problems

In the next few pages are included 3 verification examples for

reference purposes. Since the S16-01 code is similar in many

respects to the previous edition of the code (CAN/CSA S16.1-94),

the solved examples of the 1994 edition of the CISC Handbook

have been used as reference material for these examples.

Section 3B

3-27

Verification Problem No. 1

TITLE Steel beam with uniform load, wide flange section.

TYPE Static analysis, 3D beam element.

REFERENCE: CAN/CSA-S16.1-94, National Standard of Canada,

Limit States Design of Steel Structures. The Canadian

Standards Association, 1994 with CISC (Canadian

Institute of Steel Construction) handbook. CISC

Example 1 page 5_91.

PROBLEM: Find the interaction ratio, beam resistance and beam

deflection.

GIVEN: E = 200000 MPa (STEEL).

Fy = 300 Mpa CSA G40.21-M

Beam has a 8.0 m span; Ky is 1.0, Kz 1.0, unsupported

length 1.0 m

Allowable Live Load deflection, L/300 = 8000/300 = 27 mm Factored Uniform Load IS 7 kN/m DEAD, 15 kN/m LIVE.

Steel section is W410X54.

SOLUTION COMPARISON:

CAN/CSA-S16

Interaction

Ratio

Beam

Resistance

(kN*m)

Beam

Deflection

(mm)

REFERENCE 0.88 284 21

STAAD.Pro 0.883 283.20 20.81


Section 3B

3-28

****************************************************

* *

* STAAD.Pro *

* Version Bld *


* Research Engineers, Intl. *

* Date= *

* Time= *

* *

* USER ID: *

****************************************************

1. STAAD SPACE VERIFICATION CISC 1994 HANDBOOK EXAMPLE PAGE 5-91

3. * CISC EXAMPLE 1 PAGE 5-91, LIMIT STATES DESIGN, CSA-S16.1-94

4. * SIMPLY SUPPORTED BEAM WITH UNIFORM LOAD

5. * LIVE LOAD DEFLECTION OF L/300

7. UNIT MMS KN

8. JOINT COORDINATES

9. 1 0 0 0; 2 8000 0 0

10. MEMBER INCIDENCES

11. 1 1 2

13. MEMBER PROPERTY CANADIAN

14. 1 TABLE ST W410X54

16. CONSTANTS

17. E STEEL ALL

18. POISSON 0.3 ALL

20. SUPPORTS

21. 1 PINNED

22. 2 FIXED BUT MY MZ

24. UNIT METER KN

25. LOAD 1 DEAD

26. MEMBER LOAD

27. 1 UNI GY -7

29. LOAD 2 LIVE

30. MEMBER LOAD

31. 1 UNI GY -15

33. LOAD COMB 3 1.25DL + 1.5 LL

34. 1 1.25 2 1.5

36. PERFORM ANALYSIS

P R O B L E M S T A T I S T I C S

-----------------------------------

NUMBER OF JOINTS/MEMBER+ELEMENTS/SUPPORTS = 2/ 1/ 2

ORIGINAL/FINAL BAND-WIDTH= 1/ 1/ 5 DOF

TOTAL PRIMARY LOAD CASES = 2, TOTAL DEGREES OF FREEDOM = 5

SIZE OF STIFFNESS MATRIX = 1 DOUBLE KILO-WORDS

REQRD/AVAIL. DISK SPACE = 12.0/ 19641.6 MB

37. LOAD LIST 2

Section 3B

3-29

38. PRINT SECTION DISPLACEMENTS

MEMBER SECTION DISPLACEMENTS

----------------------------

UNIT =INCHES FOR FPS AND CM FOR METRICS/SI SYSTEM

MEMB LOAD GLOBAL X,Y,Z DISPL FROM START TO END JOINTS AT 1/12TH PTS

1 2 0.0000 0.0000 0.0000 0.0000 -0.5471 0.0000

0.0000 -1.0528 0.0000 0.0000 -1.4824 0.0000

0.0000 -1.8086 0.0000 0.0000 -2.0120 0.0000

0.0000 -2.0812 0.0000 0.0000 -2.0120 0.0000

0.0000 -1.8086 0.0000 0.0000 -1.4824 0.0000

0.0000 -1.0528 0.0000 0.0000 -0.5471 0.0000

0.0000 0.0000 0.0000

MAX LOCAL DISP = 2.08115 AT 400.00 LOAD 2 L/DISP= 384

************ END OF SECT DISPL RESULTS ***********

40. LOAD LIST 3

41. PARAMETER

42. CODE CANADIAN

43. TRACK 2 ALL

44. UNL 1 ALL

45. FYLD 300000 ALL

46. BEAM 1 ALL

47. CHECK CODE ALL

STAAD.PRO CODE CHECKING - (CAN/CSA-S16-01)

******************************************

ALL UNITS ARE - KNS MET (UNLESS OTHERWISE NOTED)


FX MY MZ LOCATION

=======================================================================

1 ST W410X54 (CANADIAN SECTIONS)

PASS CSA-13.8.2+ 0.883 3

0.00 C 0.00 -250.00 4.00

MEMBER PROPERTIES (UNIT = CM)

-----------------------------

CROSS SECTION AREA = 6.84E+01 MEMBER LENGTH = 8.00E+02

IZ = 1.86E+04 SZ = 9.26E+02 PZ = 1.05E+03

IY = 1.02E+03 SY = 1.15E+02 PY = 1.77E+02

MATERIAL PROPERTIES (UNIT = MPA)

--------------------------------

FYLD = 300.0 FU = 345.0

SECTION CAPACITIES (UNIT - KN,M)

---------------------------------

CR1 = 1.846E+03 CR2 = 2.732E+02

CRZ = 1.570E+03 CTORFLX = 2.732E+02

TENSILE CAPACITY = 1.805E+03 COMPRESSIVE CAPACITY = 2.732E+02

FACTORED MOMENT RESISTANCE : MRY = 4.778E+01 MRZ = 2.832E+02

FACTORED SHEAR RESISTANCE : VRY = 5.379E+02 VRZ = 4.604E+02


Section 3B

3-30

MISCELLANEOUS INFORMATION

--------------------------

NET SECTION FACTOR FOR TENSION = 1.000

KL/RY = 207.170 KL/RZ = 48.447 ALLOWABLE KL/R = 300.000

UNSUPPORTED LENGTH OF THE COMPRESSION FLANGE (M) = 1.000

OMEGA-1 (Y-AXIS) = 1.00 OMEGA-1 (Z-AXIS) = 1.00 OMEGA-2 = 1.00

SHEAR FORCE (KNS) : Y AXIS = 0.000E+00 Z AXIS = 0.000E+00

SLENDERNESS RATIO OF WEB (H/W) = 5.08E+01

48. STEEL TAKE OFF ALL

STEEL TAKE-OFF

--------------

PROFILE LENGTH(METE) WEIGHT(KN )

In Steel Takeoff the density of steel is assumed for members with no density.

ST W410X54 8.00 4.203

PRISMATIC STEEL 0.00 0.000

----------------

TOTAL = 4.203


49. FINISH

Section 3B

3-31


TITLE: Steel beam/column, wide flange section.

TYPE: Static Analysis, 3D beam element.





Handbook Example, Page 4_106.

PROBLEM: Find the interaction ratio, beam and column resistance.


Section 3B

3-32


Fy = 300 MPa CSA G40.21-M Beam/Column has a 3.7 m span, Ky is 1.0, Kz 1.0

factored axial load is 2000 kN and end moments of

200 kN*m and 300 kN*m

Steel section is W310X129


CAN/CSA-S16

Interaction

Ratio

Beam Resistance

(kN*m)

Column Resistance

(kN)

REFERENCE 0.96 583 3800

STAAD.Pro 0.98 584 3820

Section 3B

3-33

****************************************************

* *

* STAAD.Pro *

* Version Bld *



* Date= *

* Time= *

* *

* USER ID: *

****************************************************


2. *

3. * COMPRESSION + MAJOR AXIS BENDING

4. *

5. UNIT METER KN


7. 1 0 0 0; 2 0 3.7 0

8. *


10. 1 1 2

11. *


13. 1 TABLE ST W310X129

14. *

15. CONSTANTS

16. E STEEL ALL

17. POISSON STEEL ALL

18. *

19. SUPPORTS

20. 1 FIXED BUT MX MZ

21. 2 FIXED BUT FY MY MZ

22. *

23. LOAD 1 FACTORED LOAD

24. JOINT LOAD

25. 2 FY -2000

26. 2 MZ 200

27. 1 MZ 300

28. *

29. PDELTA 3 ANALYSIS


-----------------------------------






++ Adjusting Displacements 8:54:35




Section 3B

3-34

31. PRINT MEMBER FORCES

MEMBER END FORCES STRUCTURE TYPE = SPACE

-----------------

ALL UNITS ARE -- KN METE

MEMBER LOAD JT AXIAL SHEAR-Y SHEAR-Z TORSION MOM-Y MOM-Z

1 1 1 2000.00 135.14 0.00 0.00 0.00 300.00

2 -2000.00 -135.14 0.00 0.00 0.00 200.00


33. PARAMETER

34. CODE CANADIAN

35. TRACK 2 ALL

36. FYLD 300000 ALL

37. LY 3.7 ALL

38. LZ 3.7 ALL

39. CHECK CODE ALL


******************************************



FX MY MZ LOCATION

=======================================================================

1 ST W310X129 (CANADIAN SECTIONS)

PASS CSA-13.8.2C 0.980 1

2000.00 C 0.00 300.00 0.00


-----------------------------


IZ = 3.08E+04 SZ = 1.94E+03 PZ = 2.16E+03

IY = 1.00E+04 SY = 6.51E+02 PY = 9.90E+02


--------------------------------

FYLD = 300.0 FU = 345.0


---------------------------------

CR1 = 4.459E+03 CR2 = 3.820E+03

CRZ = 4.296E+03 CTORFLX = 3.820E+03




Section 3B

3-35


--------------------------







40. STEEL MEMBER TAKE OFF ALL

STEEL TAKE-OFF

--------------



ST W310X129 3.70 4.694


----------------

TOTAL = 4.694

MEMBER PROFILE LENGTH WEIGHT

(METE) (KN )

1 ST W310X129 3.70 4.694


42. FINISH


Section 3B

3-36


TITLE: Steel beam/column, wide flange section.

TYPE: Static Analysis, 3D beam element.





Handbook Example, Page 4_108.

PROBLEM: Find the interaction ratio, beam and column resistance.

Section 3B

3-37


Fy = 300 MPa CSA G40.21-M

Beam/Column has a 3.7 m span, Ky is 1.0, Kz 1.0, Lu = 3.7 m

factored axial load is 2000 kN and end moments of

200 kN*m and 300 kN*m in the strong axis and 100

kN*m at each end in the weak axis.

Steel section is W310X143.


CAN/CSA-S16

Interaction

Ratio

Beam Resistance

(kN*m)

weak strong

Column Resistance

(kN)

REFERENCE 0.998 300 653 4200

STAAD.Pro 1.00 299 650 4222


Section 3B

3-38

****************************************************

* *

* STAAD.Pro *

* Version Bld *



* Date= *

* Time= *

* *

* USER ID: *

****************************************************


2. *

3. * ( COMPRESSION + BIAXIAL BENDING )

4. *

5. UNIT METER KN


7. 1 0 0 0; 2 0 3.7 0

8. *


10. 1 1 2

11. *


13. 1 TABLE ST W310X143

14. *

15. CONSTANTS

16. E STEEL ALL

17. POISSON STEEL ALL

18. *

19. SUPPORTS

20. 1 FIXED BUT MX MZ

21. 2 FIXED BUT FY MX MY MZ

22. *

23. LOAD 1 FACTORED LOAD

24. JOINT LOAD

25. 2 FY -2000

26. 2 MZ 200

27. 2 MX 100

28. 1 MZ 300

29. 1 MX 100

30. *



-----------------------------------






Section 3B

3-39

33. PARAMETER

34. CODE CANADIAN

35. CMY 2 ALL

36. CMZ 2 ALL

37. CB 1 ALL

38. TRACK 2 ALL

39. FYLD 300000 ALL

40. CHECK CODE ALL


******************************************



FX MY MZ LOCATION

=======================================================================

* 1 ST W310X143 (CANADIAN SECTIONS)

FAIL CSA-13.8.2A 1.000 1

2000.00 C -100.00 300.00 0.00


-----------------------------


IZ = 3.47E+04 SZ = 2.15E+03 PZ = 2.41E+03

IY = 1.12E+04 SY = 7.28E+02 PY = 1.11E+03


--------------------------------

FYLD = 300.0 FU = 345.0


---------------------------------

CR1 = 4.912E+03 CR2 = 4.222E+03

CRZ = 4.737E+03 CTORFLX = 4.222E+03





--------------------------








Section 3B

3-40

41. STEEL MEMBER TAKE OFF ALL

STEEL TAKE-OFF

--------------



ST W310X143 3.70 5.171


----------------

TOTAL = 5.171

MEMBER PROFILE LENGTH WEIGHT

(METE) (KN )

1 ST W310X143 3.70 5.171


42. FINISH

3-41

Design Per Canadian Cold Formed

Steel Code

3C.1 General

Provisions of CSA S136-94, including revisions dated May, 1995,

have been implemented. The program allows design of single

(non-composite) members in tension, compression, bending,

shear, as well as their combinations. For laterally supported

members in bending, the Initiation of Yielding method has been

used. Cold work of forming strengthening effects have been

included as an option.

3C.2 Cross-Sectional Properties



Property Tables published in the "Cold-Formed Steel Design

Manual", AISI, 1996 Edition.


Channel with Lips


Angle with Lips

Angle without Lips

Z with Lips

Z without Lips

Hat

Section 3C

Design Per Canadian Cold Fomed Steel Code

Section 3C

3-42

Shape selection may be done using the member property pages of

the graphical user interface (GUI) or by specifying the section






3C.3 Design Procedure


1. Code Checking


load effects, in accordance with CSA 136. Code checking is






parameter.

2. Member Selection


shapes database (AISI standard sections) for alternative members

that pass the code check and meet the least weight criterion. In




angle, etc.) and, if a suitable replacement is found, present design





Section 3C

3-43


with Clauses 5.6.2.1 through 3 and 5.6.2.6 through 8. Cross-

sectional properties and overall slenderness of members are

checked for compliance with

Clause 5.3, Maximum Effective Slenderness Ratio for


Clause 5.4, Maximum Flat Width Ratios for Elements in

Compression

Clause 5.5, Maximum Section Depths.

The program will check member strength in accordance with

Clause 6 of the Standard as follows:

a. Resistance factors listed in Clauses 6.2 (a), (b), and (e) are used,

as applicable.

b. Members in tension

Resistance is calculated in accordance with Clauses 6.3.1 and

6.3.2.

c. Members in bending and shear

Resistance calculations are based on Clauses:

a. 6.4.1 General,

b. 6.4.2 and 6.4.2.1 Laterally Supported Members, compressive

limit stress based on Initiation of Yielding,

c. 6.4.3 Laterally Unsupported Members,

d. 6.4.4 Channels and Z-Shaped Members with Unstiffened

Flanges - additional limitations,

e. 6.4.5 Shear in Webs,

f. 6.4.6 Combined Bending and Shear in Webs.


Section 3C

3-44

a. Members in compression


a. 6.6.1.1, 6.6.1.2 (a) and (d), and 6.6.1.3 General,

b. 6.6.2 Sections Not Subject to Torsional-Flexural Buckling,

c. 6.6.3 Singly Symmetric Sections,

d. 6.6.4 Point-Symmetric Sections,

e. 6.6.5 Cylindrical Tubular Sections.

b. Members in compression and bending

Resistance calculations are based on Clause 6.7.1, Singly and

Doubly Symmetric Sections. Input for the coefficients of uniform

bending must be provided by the user.

The following table contains the input parameters for specifying

values of design variables and selection of design options.

CANADIAN COLD FORMED STEEL DESIGN PARAMETERS

Parameter

Name


BEAM 1.0 When this parameter is set to 1.0 (default), the adequacy of the member is determined by checking a total of 13 equally spaced locations along the length of the member. If the BEAM value is 0.0, the 13 location check is not conducted, and instead, checking is done only at the locations specified by the SECTION command (See STAAD manual for details). If neither the BEAM parameter nor any SECTION command is specified, STAAD will terminate the run and ask the user to provide one of those 2 commands. This rule is not enforced for TRUSS members.

Section 3C

3-45


Parameter

Name


CMZ 1.0 Coefficient of equivalent uniform bending z. See CSA 136, 6.7.2. Used for Combined axial load and bending design. Values range from 0.4 to 1.0.

CMY 0.0 Coefficient of equivalent uniform bending y. See CSA 136, 6.7.2. Used for Combined axial load and bending design. Values range from 0.4 to 1.0.

CWY 0 Specifies whether the cold work of forming strengthening effect should be included in resistance computation. See CSA 136, 5.2.



DMAX 1000.0 Maximum depth permissible for the section during member selection. This value must be provided in the current units.

DMIN 0.0 Minimum depth required for the section during member selection. This value must be provided in the current units.

FLX 1 Specifies whether torsional-flexural buckling restraint is provided or is not necessary for the member. See CSA 136, 6.6.2

Values:

0 – Section subject to torsional flexural buckling and restraint not provided

1 – restraint provided or unnecessary FU 450 MPa Ultimate tensile strength of steel in current units.

FYLD 350 MPa Yield strength of steel in current units.


Section 3C

3-46


Parameter

Name


KT 1.0 Effective length factor for torsional buckling. It is a fraction and is unit-less. Values can range from 0.01 (for a column completely prevented from torsional buckling) to any user specified large value. It is used to compute the KL/R ratio for twisting for determining the capacity in axial compression.

KY 1.0 Effective length factor for overall column buckling about the local Y-axis. It is a fraction and is unit-less. Values can range from 0.01 (for a column completely prevented from buckling) to any user specified large value. It is used to compute the KL/R ratio for determining the capacity in axial compression.

KZ 1.0 Effective length factor for overall column buckling in the local Z-axis. It is a fraction and is unit-less. Values can range from 0.01 (for a column completely prevented from buckling) to any user specified large value. It is used to compute the KL/R ratio for determining the capacity in axial compression.

LT Member length

Unbraced length for twisting. It is input in the current units of length. Values can range from 0.01 (for a column completely prevented from torsional buckling) to any user specified large value. It is used to compute the KL/R ratio for twisting for determining the capacity in axial compression.

LY Member length

Effective length for overall column buckling in the local Y-axis. It is input in the current units of length. Values can range from 0.01 (for a column completely prevented from buckling) to any user specified large value. It is used to compute the KL/R ratio for determining the capacity in axial compression.

Section 3C

3-47


Parameter

Name


LZ Member length

Effective length for overall column buckling in the local Z-axis. It is input in the current units of length. Values can range from 0.01 (for a column completely prevented from buckling) to any user specified large value. It is used to compute the KL/R ratio for determining the capacity in axial compression.

NSF 1.0 Net section factor for tension members, See CSA 136, 6.3.1.

STIFF Member length

Spacing in the longitudinal direction of shear stiffeners for stiffened flat webs. It is input in the current units of length. See section CSA 136, 6.4.5

TRACK 0 This parameter is used to control the level of detail in which the design output is reported in the output file. The allowable values are: 0 - Prints only the member number, section name, ratio,

and PASS/FAIL status. 1 - Prints the design summary in addition to that printed

by TRACK 1 2 - Prints member and material properties in addition to

that printed by TRACK 2. TSA 1 Specifies whether bearing and intermediate transverse

stiffeners satisfy the requirements of CSA 136, 6.5. If true, the program uses the more liberal set of interaction equations in 6.4.6.

Values:

0 – stiffeners do not comply with 6.5

1 – stiffeners comply with 6.5



codes.


Section 3C

3-48

3-49

Wood Design Per CSA Standard

CAN/CSA-086-01

3D.1 General Comments

The Canadian Wood Design facility in STAAD is based on

CSA086-01. A timber section library consisting of Sawn and

Glulam timber is available for member property specification.

The design philosophy of this specification is based on the

concept of limit state design. Structures are designed and







a uniform reliability is achieved for the entire structure under



In the STAAD implementation, the code checking portion of the

program checks whether code requirements for each selected

section are met and identifies the governing criteria.


implementation of CSA086-01. A detailed description of the



Analysis Methodology

Member Property Specifications

Built-in Section Library

Member Resistances

Section 3D

Design Per Canadian Timber Code

Section 3D

3-50

Design Parameters

Code Checking

Member Selection

Tabulated Results of Timber Design

Verification Examples

3D.2 Analysis Methodology

Analysis is done for the primary and combination loading

conditions provided by the user. The user is allowed complete

flexibility in providing loading specifications and using


3D.3 Member Property Specifications

For specification of member properties, for Sawn timber the timber

section library available in STAAD may be used. The next section

describes the syntax of commands used to assign properties from

the built-in timber table.

For Glulam timber, member properties can be specified using the

YD(depth) and ZD(width) specifications and selecting

Combination and Species specifications from the built -in table.

The assignment is done with the help of the PRISMATIC option

which is explained in STAAD‟s Technical Reference Manual.

3D.4 Built-in Section Library


timber tables are to be referenced for member property

specification. These properties are stored in a database file. If

called for, the properties are also used for member design.

Section 3D

3-51

Following are the description of the different types of species

combination available:

Douglas Fir-Larch

The following example illustrates the specification of Douglas Fir -

Larch species combination.

100 TO 150 TABLE ST DFL_SelStr_2X2_BM

Hem-Fir

Designation of Hem-Fir species combination in STAAD is as

follows.

100 TO 150 TABLE ST Hem-Fir_SelStr_2X10_BM

Northern Species

Designation of Northern species combination in STAAD is as

follows.

100 TO 150 TABLE ST Northern_SelStr_3X12_BM

Spruce-Pine-Fir

Designation of Spruce-Pine-Fir species combination in STAAD is

as follows.

100 TO 150 TABLE ST SPF_SelStr_3X8_BM

DFL_SelStr_2X2_BM

Species

Combination

Grade Nominal size

Size classification


Section 3D

3-52

Glu Laminated timber

Designation of Glu-lam timber in STAAD involves defining the

material, specifying the dimensions, and associating the material

with the member through the CONSTANTS command.

UNIT CM KN


ISOTROPIC GLT_D.Fir-L-24f-EX

E 51611.7

POISSON 0.15

DENSITY 2.5e-005

ALPHA 1.2e-011

END DEFINE MATERIAL

MEMBER PROPERTY TIMBER CANADIAN

1 PRIS YD 12 ZD 6

CONSTANTS

MATERIAL GLT_D.Fir-L-24f-EX MEMB 1

GLT_D.Fir-L-24f-EX

Timber type

Species

Grade

Section 3D

3-53

Sample input file to demonstrate usage of Canadian timber

STAAD PLANE EXAMPLE FOR DIMENSIONAL LUMBER

UNIT FEET POUND

JOINT COORDINATES

1 0 0 0; 2 6 0 0; 3 12 0 0; 4 18 0 0;

5 24 0 0; 6 6 3 0; 7 12 6 0; 8 18 3 0;

MEMBER INCIDENCES

1 1 2; 2 2 3; 3 3 4; 4 4 5; 5 1 6; 6 6 7; 7 7 8; 8 8 5;

9 2 6; 10 3 7; 11 4 8; 12 6 3; 13 3 8;

UNIT FEET POUND


ISOTROPIC SPF_SelStr_4X10_BM

E 1224

POISSON 0.15

DENSITY 25

ALPHA 5.5e-006

END DEFINE MATERIAL

MEMBER PROPERTY tim can

1 TO 4 9 TO 11 TABLE ST SPF_SelStr_4X10_BM

5 TO 8 12 13 TABLE ST SPF_SelStr_4X10_BM

CONSTANTS

MATERIAL SPF_SelStr_4X10_BM memb 1 TO 4 9 TO 11

MATERIAL SPF_SelStr_4X10_BM memb 5 TO 8 12 13


FINISH


Section 3D

3-54

3D.5 Member Resistance


procedures outlined in section 5 (for sawn lumber) and 6(for

Glulam) of CSA086-01.

These depend on several adjustment factors as fol lows

1. KD = Load duration factor (Clause 4.3.2.2-CSA086-01, Table

4.3.2.2)

2. KH = System factor (Clause 5.4.4 and 6.4.3 and Table

5.4.4 -CSA086-01)

3. K_T = Treatment factor (Clause 5.4.3 and 6.4.4 -CSA086-

01)

4. KSB = Service condition factor applicable to Bending at

extreme fibre (Table 5.4.2 and 6.4.2 -CSA086-01)

5. KSV = Service condition factor applicable to longitudinal

shear (Table 5.4.2 and 6.4.2 CSA086-01)

6. KSC = Service condition factor applicable to Compression

parallel to the grain (Table 5.4.2 and 6.4.2 CSA086-01)

7. K_SCP = Service condition factor applicable to Compression

perpendicular to the grain (Table 5.4.2 and 6.4.2 CSA086-01)

8. KSE = Service condition factor applicable to modulus of

elasticity (Table 5.4.2 and 6.4.2 CSA086-01)

9. KST = Service condition factor applicable to tension parallel

to the grain (Table 5.4.2 and 6.4.2 CSA086-01)

10. KZB = Size factor applicable to bending (Clause 5.4.5 and

Table 5.4.5 -CSA086-01)

11. KZV = size factor applicable to shear(Clause 5.4.5 and Table

5.4.5 -CSA086-01)

12. KZT = size factor applicable to tension parallel to grain

(Clause 5.4.5 and Table 5.4.5 -CSA086-01)

13. KZCP = size factor applicable to compression perpendicular to

grain (Clause 5.4.5 and Table 5.4.5 -CSA086-01)

14. K_ZC = size factor applicable to compression parallel to grain

(Clause 5.4.5 and Table 5.4.5 -CSA086-01)

15. CHIX = Curvature factor (Clause 6.5.6.5.2-CSA086-01)

Section 3D

3-55

16. CV = shear load coefficient (Table 6.5.7.4A- CSA086-01)

17. KN = Notch factor(Clause 5.5.5.4-CSA086-01)

The user has to give all these factors as input according to the

classification of timber and stress grade.

Explained here is the procedure adopted in STAAD for calculating

the member resistances.

Axial Tension

i. For Sawn timber

The criterion governing the capacity of tension members is

based on one limit state. The limit state involves fracture at

the section with the minimum effective net area. The net

section area may be specified by the user through the use of

the parameter NSF (see Table 3B.1). STAAD calculates the

tension capacity of a member based on this limit state per

Clause 5.5.9 of CSA086-01.

ii. For Glulam timber

The design of glulam tension members differs from sawn

timber since CSA 086-01 assigns different specified strength

for gross and net section. The specified strength at net section

is slightly higher than the strength of the gross section.

Therefore, Glulam tension members are designed based on

two limit states. The first one is the limit state of yielding in

the gross section. The second limit state involves fracture at

the section with the minimum effective net area. The net -

section area may be specified by the user through the use of

the parameter NSF (see Table 3B.1). STAAD calculates the

tension capacity of a member based on these two limits states

per Clause.6.5.11 of CSA086-01.

Axial Compression


Clause.5.5.6 and Clause.6.5.8.4 of CSA086-01. The equations

presented in this section of the code assume that the compressive


Section 3D

3-56

resistance is a function of the compressive strength of the gross

section (Gross section Area times the Yield Strength) as well as

the slenderness factor (Kc). The effective length for the

calculation of compression resistance may be provided through the

use of the parameters KX, KY, KZ, LX, LY and LZ (see Table

3B.1).

Bending

The bending resistance of Sawn members are determined based on

Clause 5.5.4 of CSA086-01 and for glulam members are

determined based on Clause 6.5.6.5 of CSA086-01. The allowable

stress in bending is multiplied by Lateral stability factor, KL to

take in account whether lateral support is provided at points of

bearing to prevent lateral displacement and rotation



and uni-axial or biaxial bending is obtained through the use of

interaction equations. Clause 5.5.10 and 6.5.12 of the code

provides the equations for this purpose. If the summation of the

left hand side of these equations exceeds 1.0 or the allowable

value provided using the RATIO parameter (see Table 3B.1), the

member is considered to have FAILed under the loading condition.


The member strength for sections subjected to axial tension and

uniaxial or biaxial bending is obtained through the use of

interaction equations. Clause 5.5.10 and 6.5.12 of the code

provides the equations for this purpose. If the summation of the

left hand side of these equations exceeds 1.0 or the allowable

value provided using the RATIO parameter (see Table 3B.1), the

member is considered to have FAILed under the loading condition.

Section 3D

3-57

Shear


equations of Clause 5.5.5 and 6.5.7.2 of the code. Once this is

obtained, the ratio of the shear force acting on the cross section to

the shear resistance of the section is calculated. If any of the ratios

(for both local Y & Z axes) exceed 1.0 or the allowable value

provided using the RATIO parameter (see Table 3B.1), the section

is considered to have failed under shear.

3D.6 Design Parameters

The design parameters outlined in Table below may be used to


design decisions from the engineer to the program and thus allows


specific needs.








Canadian Timber design parameters

Parameter

Name

Default

Value

Description

Nsf 1.0 Net section factor for tension members

KX 1.0 K value for flexural torsional buckling

KY 1.0 K value in local Y-axis, usually minor axis

KZ 1.0 K value in local Z-axis, usually major axis

LX Member

length Length for flexural torsional buckling


Section 3D

3-58


Parameter

Name

Default

Value

Description

LY Member

length

Length in local Y axis for slenderness value

KL/r

LZ Member

length

Length in local Z axis for slenderness value

KL/r

KD 1.0 Load Duration Factor [Clause.4.3.2, Table

4.3.2]

KH 1.0 System Factor [Clause 5.4.4/6.4.3, Table

5.4.4]

K_T 1.0 Treatment Factor [Clause 5.4.3/6.4.4]

KSB 1.0

Service Condition Factor for Bending at

Extreme Fibre

Applicable for bending at extreme fibre

[Table 5.4.2 and 6.4.2]

KSV 1.0

Service Condition Factor for Shear,

Applicable for longitudinal shear [Table 5.4.2

and 6.4.2]

KSC 1.0

Service Condition Factor for Compression,

Applicable for compression parallel to grain

[Table 5.4.2 and 6.4.2]

KSE 1.0

Service Condition Factor for Modulus of

Elasticity,

Applicable for modulus of elasticity [Table

5.4.2 and 6.4.2]

KST 1.0

Service Condition Factor for Tension,

Applicable for tension parallel to grain [Table

5.4.2 and 6.4.2]

KZB 1.0

Size Factor for Bending,

Applicable for bending [Clause.5.4.5 and

Table 5.4.5]

KZV 1.0 Size Factor for Shear [Clause 5.4.5 and Table

5.4.5]

Section 3D

3-59


Parameter

Name

Default

Value

Description

KZT 1.0

Size Factor for Tension,

Applicable for tension parallel to grain

[Clause 5.4.5 and Table 5.4.5]

KZCP 1.0

Size Factor for Compression,

Applicable for compression perpendicular to

grain [Clause .5.4.5 and Table 5.4.5]

K_ZC 1.0

Size Factor for Compression,

Applicable for compression parallel to grain

[Clause 5.4.5 and Table 5.4.5]

CV 1.0 Shear Load Coefficient [Table 6.5.7.4A]

KN 1.0 Notch Factor [Clause 5.4.7.2.2]

K_SCP 1.0

Service Condition Factor for Compression,

Applicable for compression perpendicular to

grain [Clause 5.4.2 and Table 6.4.2]

CHIX 1.0 Curvature Factor for Compression [Clause

6.5.6.5.2]

RATIO 1.0 Permissible Ratio of Actual to Allowable

Value

3D.7 Code Checking



checked as per the CSA086-01 requirements.


sections of the members. The code checking output labels th e


governing load case, location (distance from the start joint) and



Section 3D

3-60

PARAMETER

CODE TIMBER CAN

KD 0.99 ALL

KH 0.99 ALL

K_T 0.99 ALL

KSB 0.99 ALL

KSV 0.99 ALL

KSC 0.99 ALL

KSE 0.99 ALL

KST 0.99 ALL

KZB 0.99 ALL

KZV 0.99 ALL

KZT 0.99 ALL

KZCP 0.99 ALL

K_ZC 0.99 ALL

CV 0.99 ALL

KN 0.99 ALL

K_SCP 0.99 ALL

CHIX 0.99 ALL

RATIO 0.99 ALL

CHECK CODE ALL

FINISH

3D.8 Member Selection

Member selection based CSA086-2001 is not available.

3D.9 Tabulated Results of Timber Design



the CSA086-01 specification, which governed the design.

Section 3D

3-61

Pu = Actual Load in Compression

Tu = Actual Load in Tension

Muy = Ultimate moment in y direction

Muz = Ultimate moment in z direction

V = Ultimate shear force

SLENDERNESS_Y = Actual Slenderness ratio in y direction

SLENDERNESS_Z = Actual Slenderness ratio in z direction

PY = Factored Compressive capacity in y direction

PZ = Factored Compressive capacity in z direction

T = Factored tensile capacity

MY = Factored moment of resistance in y direction

MZ = Factored moment of resistance in z direction

V = Factored shear resistance

SLENDERNESS = Allowable slenderness ratio

3D.10 Verification Problems


reference purposes.


Section 3D

3-62

Verification Problem: 1

Objective: - To determine the Canadian Glulam section column in

axial compression. Column is effectively pinned at

both ends and braced at mid-height in all direction..

Design Code: - Canadian wood design code (CSA:086-01)

Reference: - Example 4, page 116, Canadian Wood Design Manual, 2001

Given: - Length = 9000mm

Comparison: -

Solution Design Strength (kN)

Theory 295

STAAD 293.739

Difference -0.427 %

Input: -

STAAD PLANE EXAMPLE FOR GLULAM DESIGN INPUT FILE:

GLULAMCOLUMN.STD

START JOB INFORMATION

ENGINEER DATE 10-JUN-05

END JOB INFORMATION

INPUT WIDTH 79

UNIT METER KN

JOINT COORDINATES

1 0 0 0; 2 0 9 0;

MEMBER INCIDENCES

1 1 2;

UNIT INCHES KIP


ISOTROPIC GLT_SPRUCE-PINE-12C-E

E 9.7

POISSON 0.15

DENSITY 1.44676e-005

ALPHA 5.5e-006

END DEFINE MATERIAL

UNIT FEET POUND

Section 3D

3-63


1 PRIS YD 0.748031 ZD 0.574147

UNIT INCHES KIP

CONSTANTS

MATERIAL GLT_SPRUCE-PINE-12C-E MEMB 1

SUPPORTS

1 PINNED

UNIT METER KN

LOAD 1 LOADTYPE None TITLE LOAD CASE 1

JOINT LOAD

2 FY -214

PERFORM ANALYSIS

PARAMETER

CODE TIMBER CANADIAN

KY 0.5 ALL

KZ 0.5 ALL

CHECK CODE ALL

FINISH

Relevant portion of Output:-

STAAD.Pro CODE CHECKING - (S086)

***********************



FX MY MZ LOCATION

=======================================================================

1 175.00X228.00 CANADIAN GLULAM GRADE:GLT_SPRUCE-PINE-12C-E

PASS CL.5.5.10/6.5 0.728 1

214.00 C 0.00 0.00 0.0000

|--------------------------------------------------------------------------|

| LEZ = 4500.000 LEY = 4500.000 LUZ = 9000.000 LUY = 9000.000mm |

| |

| KD = 1.000 KH = 1.000 KT = 1.000 KSB = 1.000 KSV = 1.000 |

| KSC = 1.000 K_SCP = 1.000 KSE = 1.000 KST = 1.000 KZB = 1.000 |

| KZV = 1.000 KZT = 1.000 KZCP = 1.000 K_ZC = 1.000 CHIX = 1.000 |

| CV = 1.000 KN = 1.000 |

| |

| ACTUAL LOADS : (KN-m) |

| Pu = 214.000 |

| Tu = 0.000 |

| Muy = 0.000 |

| Muz = 0.000 |

| V = 0.000 |

| SLENDERNESS_Y = 19.737 |

| SLENDERNESS_Z = 25.714 |

| ALLOWABLE CAPACITIES OF THE SECTION: (KN-m) |

| PY = 413.943 |

| PZ = 293.793 |

| T = 0.000 |

| MY = 0.000 |

| MZ = 0.000 |

| V = 0.000 |

| SLENDERNESS = 50.000 |

|--------------------------------------------------------------------------|

37. FINISH


Section 3D

3-64


Objective: - To determine the bending capacity of a Canadian

Glulam section single span floor beam. The

compression edge assumed fully supported.



Given: - Length =7500mm, Beam Spacing = 5000mm, Standard load

condition, Dry service condition, Untreated

Comparison: -

Input: -

STAAD PLANE EXAMPLE FOR GLULAM DESIGN INPUT FILE: glulamBEAM.STD



END JOB INFORMATION

INPUT WIDTH 79

UNIT METER KN

JOINT COORDINATES

1 0 0 0; 2 7.5 0 0

MEMBER INCIDENCES

1 1 2

UNIT INCHES KIP

Solution Design

Strength in

bending (kN-

m)

Design

Strength in

shear (kN)

Theory 208 101

STAAD 208.323 100.776

Difference 0.155 % -0.221 %

Section 3D

3-65


ISOTROPIC GLT_SPRUCE-PINE-12C-E

E 9.7

POISSON 0.15

DENSITY 1.44676E-005

ALPHA 5.5E-006

ISOTROPIC GLT_D.FIR-L-20F-E

E 12.4

POISSON 0.15


ALPHA 5.5E-006

ISOTROPIC CONCRETE

E 3150

POISSON 0.17

DENSITY 8.68E-005

ALPHA 5.5E-006

DAMP 0.05

END DEFINE MATERIAL

UNIT FEET POUND


1 PRIS YD 2.11942 ZD 0.426508

UNIT INCHES KIP

CONSTANTS

MATERIAL GLT_D.FIR-L-20F-E MEMB 1

SUPPORTS

1 2 PINNED

UNIT METER KN

LOAD 1 LOADTYPE NONE TITLE LOAD CASE 1

MEMBER LOAD

1 UNI GY -27.1

PERFORM ANALYSIS

PARAMETER


CHECK CODE ALL

FINISH


Section 3D

3-66



***********************



FX MY MZ LOCATION

=======================================================================

1 130.00X646.00 CANADIAN GLULAM GRADE:GLT_D.FIR-L-20F-E

FAIL CL.5.5.5/6.5. 1.008 1

0.00 T 0.00 0.00 0.0000

|--------------------------------------------------------------------------|

| LEZ = 7500.000 LEY = 7500.000 LUZ = 7500.000 LUY = 7500.000mm |

| |

| KD = 1.000 KH = 1.000 KT = 1.000 KSB = 1.000 KSV = 1.000 |



| CV = 1.000 KN = 1.000 |

| |


| Pu = 0.000 |

| Tu = 0.000 |

| Muy = 0.000 |

| Muz = 0.000 |

| V = 101.625 |




| PY = 0.000 |

| PZ = 0.000 |

| T = 0.000 |

| MY = 41.923 |

| MZ = 208.323 |

| V = 100.776 |


|--------------------------------------------------------------------------|

46. FINISH

Section 3D

3-67


Objective: - To determine the capacity of a Canadian Glulam

section in axial tension.


Reference: - Example 3, page 158, Canadian Wood Design

Manual, 2001

Given: - Dry service condition, Untreated

Comparison: -

Solution Design Strength in

Tension (kN)

Theory 257

STAAD 256.636

Difference -0.141 %

Input: -

STAAD PLANE EXAMPLE FOR GLULAM DESIGN INPUT FILE: glulamTENSION.STD



END JOB INFORMATION

INPUT WIDTH 79

UNIT METER KN

JOINT COORDINATES

1 0 0 0; 2 0 9 0

MEMBER INCIDENCES

1 1 2

UNIT INCHES KIP


ISOTROPIC GLT_SPRUCE-PINE-14T-E

E 10.7

POISSON 0.15



Section 3D

3-68

ALPHA 5.5E-006

ISOTROPIC CONCRETE

E 3150

POISSON 0.17

DENSITY 8.68E-005

ALPHA 5.5E-006

DAMP 0.05

END DEFINE MATERIAL

UNIT FEET POUND


1 PRIS YD 0.872702 ZD 0.262467

UNIT INCHES KIP

CONSTANTS

MATERIAL GLT_SPRUCE-PINE-14T-E MEMB 1

SUPPORTS

1 PINNED

UNIT METER KN

LOAD 1 LOADTYPE NONE TITLE LOAD CASE 1

JOINT LOAD

2 FY 250


PARAMETER


KY 0.5 ALL

KZ 0.5 ALL

CHECK CODE ALL

FINISH

Section 3D

3-69



***********************



FX MY MZ LOCATION

=======================================================================

1 80.00X266.00 CANADIAN GLULAM GRADE:GLT_SPRUCE-PINE-14T-E

PASS CL.5.5.10/6.5 0.974 1

250.00 T 0.00 0.00 0.0000

|--------------------------------------------------------------------------|

| LEZ = 4500.000 LEY = 4500.000 LUZ = 9000.000 LUY = 9000.000mm |

| |

| KD = 1.000 KH = 1.000 KT = 1.000 KSB = 1.000 KSV = 1.000 |



| CV = 1.000 KN = 1.000 |

| |


| Pu = 0.000 |

| Tu = -250.000 |

| Muy = 0.000 |

| Muz = 0.000 |

| V = 0.000 |


| PY = 0.000 |

| PZ = 0.000 |

| T = 256.636 |

| MY = 0.000 |

| MZ = 0.000 |

| V = 0.000 |

|--------------------------------------------------------------------------|


Section 3D

3-70


Objective: - To determine the Canadian Sawn section column in

axial compression. Column is effectively pinned at

both ends.



Given: - Unbraced Length = 5000mm

Comparison: -


Theory 130

STAAD 129.223

Difference -0.597 %

Input: -

STAAD PLANE EXAMPLE FOR DIMENSIONAL LUMBER INPUT FILE: sawn_ lumber_ COLUMN.STD



END JOB INFORMATION

UNIT FEET POUND

JOINT COORDINATES

1 0 0 0; 2 0 16.4042 0

MEMBER INCIDENCES

1 1 2


ISOTROPIC DFL_NO2_8X8_POST

E 1.368E+006

POISSON 0.15

DENSITY 25

ALPHA 5.5E-006

END DEFINE MATERIAL

UNIT METER KN

CONSTANTS

Section 3D

3-71

MATERIAL DFL_NO2_8X8_POST MEMB 1

UNIT FEET POUND


1 TABLE ST DFL_NO2_8X8_POST

SUPPORTS

1 PINNED

UNIT METER KN

LOAD 1 DEAD+LIVE LOAD

JOINT LOAD

2 FY -114


PARAMETER


KSC 0.91 ALL

K_ZC 1.05 ALL

CHECK CODE

FINISH



***********************



FX MY MZ LOCATION

=======================================================================

1 ST DFL_NO2_8X8_POST

PASS CL.5.5.10/6.5.12 0.882 1

114.00 C 0.00 0.00 0.0000

|--------------------------------------------------------------------------|

| LEZ = 5000.000 LEY = 5000.000 LUZ = 5000.000 LUY = 5000.000mm |

| |

| KD = 1.000 KH = 1.000 KT = 1.000 KSB = 1.000 KSV = 1.000 |



| CV = 1.000 KN = 1.000 |

| |


| Pu = 114.000 |

| Tu = 0.000 |

| Muy = 0.000 |

| Muz = 0.000 |

| V = 0.000 |




| PY = 129.223 |

| PZ = 129.223 |

| T = 0.000 |

| MY = 0.000 |

| MZ = 0.000 |

| V = 0.000 |


|--------------------------------------------------------------------------|


Section 3D

3-72


Objective: - To determine the bending capacity of a Canadian

sawn section single span floor beam.


Reference: - Example 1, page 58, Canadian Wood Design Manual,

2001

Given: - Length =6000mm, Beam Spacing = 3000mm, Standard

load condition, Dry service condition, Untreated

Comparison: -


bending (kN-m)

Design Strength

in shear (kN)

Theory 79.8 46.1

STAAD 79.732 46.170

Difference -0.085 % No

Input: -

STAAD PLANE EXAMPLE FOR DIMENSIONAL LUMBER: SAWN_LUMBER_BEAM.STD START JOB INFORMATION ENGINEER DATE 08-JUN-05 END JOB INFORMATION UNIT METER KN JOINT COORDINATES 1 0 0 0; 2 6 0 0; 3 3 0 0; MEMBER INCIDENCES 1 1 3; 2 3 2; UNIT FEET POUND DEFINE MATERIAL START ISOTROPIC DFL_NO1_10X16_BM E 1.728e+006 POISSON 0.15 DENSITY 25 ALPHA 5.5e-006 END DEFINE MATERIAL UNIT METER KN CONSTANTS

Section 3D

3-73

MATERIAL DFL_NO1_10X16_BM MEMB 1 2 UNIT FEET POUND MEMBER PROPERTY TIMBER CANADIAN 1 2 TABLE ST DFL_NO1_10X16_BM SUPPORTS 1 2 FIXED UNIT METER KN LOAD 1 DEAD+LIVE LOAD MEMBER LOAD 1 2 UNI GY -16.4 PERFORM ANALYSIS PARAMETER CODE TIMBER CANADIAN KD 1.0 ALL K_T 1.0 ALL KSB 1.0 ALL KZB 0.90 ALL KZV 0.90 ALL K_ZC 1.05 ALL CHECK CODE ALL FINISH




FX MY MZ LOCATION

=======================================================================

2 ST DFL_NO1_10X16_BM

FAIL CL.5.5.5/6.5.6 1.066 1

0.00 T 0.00 49.20 3.0000

|--------------------------------------------------------------------------|

| LEZ = 3000.000 LEY = 3000.000 LUZ = 3000.000 LUY = 3000.000mm |

| |

| KD = 1.000 KH = 1.000 KT = 1.000 KSB = 1.000 KSV = 1.000 |



| CV = 1.000 KN = 1.000 |

| |


| Pu = 0.000 |

| Tu = 0.000 |

| Muy = 0.000 |

| Muz = 49.200 |

| V = -49.200 |




| PY = 0.000 |

| PZ = 0.000 |

| T = 0.000 |

| MY = 79.800 |

| MZ = 79.732 |

| V = 46.170 |


|--------------------------------------------------------------------------|


Section 3D

3-74


Objective: - To determine the capacity of a Canadian Sawn section in axial

tension.



Given: - Dry service condition, Untreated

Comparison: -


Tension (kN)

Theory 185

STAAD 184.338

Difference -0.357%

Input: -

STAAD PLANE EXAMPLE FOR DIMENSIONAL LUMBER SAWN_LUMBER_TENSION.STD START JOB INFORMATION ENGINEER DATE 08-JUN-05 END JOB INFORMATION UNIT FEET POUND JOINT COORDINATES 1 0 0 0; 2 0 16.4042 0; MEMBER INCIDENCES 1 1 2; DEFINE MATERIAL START ISOTROPIC DFL_NO1_6X8_BM E 1.728e+006 POISSON 0.15 DENSITY 25 ALPHA 5.5e-006 END DEFINE MATERIAL UNIT METER KN CONSTANTS MATERIAL DFL_NO1_6X8_BM MEMB 1

Section 3D

3-75

UNIT FEET POUND MEMBER PROPERTY TIMBER CANADIAN 1 TABLE ST DFL_NO1_6X8_BM SUPPORTS 1 PINNED UNIT METER KN LOAD 1 DEAD+LIVE LOAD JOINT LOAD 2 FY 144 PERFORM ANALYSIS PRINT STATICS CHECK PARAMETER CODE TIMBER CANADIAN KH 1.1 ALL KSC 0.91 ALL K_ZC 1.05 ALL CHECK CODE ALL FINISH



***********************



FX MY MZ LOCATION

=======================================================================

1 ST DFL_NO1_6X8_BM

PASS CL.5.5.10/6.5.12 0.781 1

144.00 T 0.00 0.00 0.0000

|--------------------------------------------------------------------------|

| LEZ = 5000.000 LEY = 5000.000 LUZ = 5000.000 LUY = 5000.000mm |

| |

| KD = 1.000 KH = 1.100 KT = 1.000 KSB = 1.000 KSV = 1.000 |



| CV = 1.000 KN = 1.000 |

| |


| Pu = 0.000 |

| Tu = -144.000 |

| Muy = 0.000 |

| Muz = 0.000 |

| V = 0.000 |


| PY = 0.000 |

| PZ = 0.000 |

| T = 184.338 |

| MY = 0.000 |

| MZ = 0.000 |

| V = 0.000 |

|--------------------------------------------------------------------------|


Section 3D

3-76

Section 4

Chinese Codes

Kjahds;akh

4-1

Concrete Design Per GB50010-2002


STAAD has the capabilities for performing concrete design per

GB50010-2002. It can calculate the reinforcement needed for

sections assigned through the PRISMATIC attribute. The concrete

design calculations are based on the limit state method of

GB50010-2002.



designed.

For Beams Prismatic (Rectangular, Square, Tee and

Trapezoidal)






input:

Section 4A


Section 4A

4-2

UNIT MM

MEMBER PROPERTY

1 3 TO 7 9 PRISM YD 450. ZD 250.

11 13 PR YD 350.

14 TO 16 PRIS YD 400. ZD 750. YB 300. ZB 200 .

will be done accordingly. In the above input, the first set of

members are rectangular (450 mm depth and 250mm width) and

the second set of members, with only depth and no width provided,

will be assumed to be circular with 350 mm diameter. The third set

numbers in the above example represents a T-shape with 750 mm

flange width, 200 width, 400 mm overall depth and 100 mm flange

depth (See section 6.20.2). The program will determine whether

the section is rectangular, flanged or circular and the beam or

column design



perform design as per GB50010-2002. Default parameter values

have been selected such that they are frequently used numbers for

conventional design requirements. These values may be changed to

suit the particular design being performed. Table 9A.1 of this

manual contains a complete list of the available parameters and

their default values. It is necessary to declare length and force

units as Millimeter and Newton before performing the concrete

design. Please note as per GB50010-2002, STAAD supports

Characteristic Values of Concrete Strength and Design Value of

Strength of Steel Bar only as per Table 4.1.4 and Table 4.2.3-1

respectively.

4A.5 Beam Design

Beams are designed for flexure, shear and torsion. If required the

effect the axial force may be taken into consideration. For all

Section 4A

4-3

these forces, all active beam loadings are prescanned to identify

the critical load cases at different sections of the beams. The total

number of sections considered is 13( e.g.

0.,.1,.2,.25,.3,.4,.5,.6,.7,.75,.8,.9 and 1). All of these sections are

scanned to determine the design force envelopes.

Design for Flexure




above mentioned sections. Each of these sections are designed to

resist both of these critical sagging and hogging moments. Where

ever the rectangular section is inadequate as singly reinforced

section, doubly reinforced section is tried. However, presently the

flanged section is designed only as singly reinforced section under

sagging moment. It may also be noted all flanged sections are

automatically designed as rectangular section under hogging

moment as the flange of the beam is ineffective under hogging

moment. Flexural design of beams are performed in two passes. In

the first pass, effective depths of the sections are determined with

the assumption of single layer of assumed reinforcement and




again in a second pass taking into account of the changed effective

depths of sections calculated on the basis of reinforcement provide

after the preliminary design. Final provision of flexural

reinforcements is made then. Efforts have been made to meet the

guideline for the reinforcement detailing as per GB50010-2002

Although exact curtailment lengths are not mentioned explicitly in

the design output (finally which will be more or less guided by the

detailer taking into account of other practical considera tion), user

has the choice of printing reinforcements provided by STAAD at

11 equally spaced sections from which the final detail drawing can

be prepared.


Section 4A

4-4

Design for Shear


torsional moments. Shear design are performed at 11 equally

spaced sections (0.to 1.) for the maximum shear forces amongst

the active load cases and the associated torsional moments. Shear

capacity calculation at different sections without the shear

reinforcement is based on the actual tensile reinforcement

provided by STAAD program. Two-legged stirrups are provided to

take care of the balance shear forces acting on these sections.

Beam Design Output

The default design output of the beam contains flexural and shear

reinforcement provided at 5 equally spaced (0,.25,.5,.75 and 1.)

sections along the length of the beam. User has option to get a

more detail output. All beam design outputs are given in IS units.

An example of rectangular beam design output with the default

output option (TRACK 0.0) is presented below:

Section 4A

4-5

============================================================================ B E A M N O. 12 D E S I G N R E S U L T S C20 HRB400 (Main) HRB400 (Sec.) LENGTH: 4000.0 mm SIZE: 250.0 mm X 350.0 mm COVER: 30.0 mm DESIGN LOAD SUMMARY (KN MET) ---------------------------------------------------------------------------- SECTION |FLEXTURE (Maxm. Sagging/Hogging moments)| SHEAR (in mm) | P MZ MX Load Case | VY MX Load Case ---------------------------------------------------------------------------- 0.0 | 0.00 0.00 0.00 4 | 29.64 1.23 4

| 0.00 -25.68 1.23 4 | 400.0 | 0.00 0.00 0.00 4 | 27.97 1.23 4 | 0.00 -16.05 1.23 4 | 800.0 | 0.00 0.00 0.00 4 | 25.12 1.23 4 | 0.00 -7.17 1.23 4 | 1200.0 | 0.00 0.97 0.49 5 | 21.11 1.23 4

| 0.00 -0.14 1.32 6 | 1600.0 | 0.00 6.77 1.23 4 | 15.93 1.23 4 | 0.00 0.00 0.00 4 |

2000.0 | 0.00 11.06 1.23 4 | 9.59 1.23 4 | 0.00 0.00 0.00 4 | 2400.0 | 0.00 13.04 1.23 4 | 2.08 1.23 4

| 0.00 0.00 0.00 4 | 2800.0 | 0.00 12.45 1.23 4 | -5.43 1.23 4 | 0.00 0.00 0.00 4 | 3200.0 | 0.00 9.55 1.23 4 | -11.77 1.23 4 | 0.00 0.00 0.00 4 | 3600.0 | 0.00 4.73 1.23 4 | -16.95 1.23 4

| 0.00 0.00 0.00 4 | 4000.0 | 0.00 0.00 0.00 4 | -25.48 1.23 4 | 0.00 -17.36 1.23 4 | ----------------------------------------------------------------------------

SUMMARY OF REINF. AREA (Sq.mm) ---------------------------------------------------------------------------- SECTION 0.0 mm 1000.0 mm 2000.0 mm 3000.0 mm 4000.0 mm ----------------------------------------------------------------------------

TOP 259.04 161.29 0.00 0.00 176.31 REINF. (Sq. mm) (Sq. mm) (Sq. mm) (Sq. mm) (Sq. mm)

BOTTOM 0.00 160.78 160.78 160.78 0.00 REINF. (Sq. mm) (Sq. mm) (Sq. mm) (Sq. mm) (Sq. mm) ----------------------------------------------------------------------------

SUMMARY OF PROVIDED REINF. AREA

---------------------------------------------------------------------------- SECTION 0.0 mm 1000.0 mm 2000.0 mm 3000.0 mm 4000.0 mm ---------------------------------------------------------------------------- TOP 4-10Ø 3-10Ø 2-10Ø 2-10Ø 3-10Ø REINF. 1 layer(s) 1 layer(s) 1 layer(s) 1 layer(s) 1 layer(s)

BOTTOM 2-12Ø 2-12Ø 2-12Ø 2-12Ø 2-12Ø REINF. 1 layer(s) 1 layer(s) 1 layer(s) 1 layer(s) 1 layer(s)

SHEAR 2 legged 8Ø 2 legged 8Ø 2 legged 8Ø 2 legged 8Ø 2 legged 8Ø REINF. @ 100 mm c/c @ 100 mm c/c @ 100 mm c/c @ 100 mm c/c @ 100 mm c/c

----------------------------------------------------------------------------

============================================================================


Section 4A

4-6

4A.6 Column Design



The loading which yield maximum reinforcement is called the


circular sections. By default, square and rectangular columns and

designed with reinforcement distributed on each side equally for

the sections under biaxial moments and with reinforcement

distributed equally in two faces for sections under uniaxial

moment. User may change the default arrangement of the

reinforcement with the help of the parameter RFACE (see Table

4A.1). Depending upon the member lengths, section dimensions

and effective length coefficients specified by the user STAAD

automatically determine the criterion (short or long) of the column

design. All major criteria for selecting longitudinal and transverse

reinforcement as stipulated by GB50010-2002 have been taken

care of in the column design of STAAD.

Column Design Output

Default column design output (TRACK 0.0) contains the

reinforcement provided by STAAD and the capacity of the section.

With the option TRACK 1.0, the output contains intermediate

results such as the design forces, effective length coefficients,

additional moments etc. A special output TRACK 9.0 is introduced

to obtain the details of section capacity calculations. All design

output is given in SI units. An example of a long column design

output (with option TRACK 1.0) is given below.

Section 4A

4-7

============================================================================ C O L U M N No. 1 D E S I G N R E S U L T S C20 HRB400 (Main) HRB400 (Sec.)

LENGTH: 3000.0 mm CROSS SECTION: 250.0 mm dia. COVER: 40.0 mm ** GUIDING LOAD CASE: 5 BRACED LONG COLUMN

DESIGN FORCES (KNS-MET) ----------------------- DESIGN AXIAL FORCE (Pu) : 62.0

About Z About Y INITIAL MOMENTS : 2.21 32.29

MOMENTS DUE TO MINIMUM ECC. : 1.24 1.24 SLENDERNESS RATIOS : 12.00 12.00 MOMENTS DUE TO SLENDERNESS EFFECT : 1.12 1.12 MOMENT REDUCTION FACTORS : 1.00 1.00 ADDITION MOMENTS (Maz and May) : 1.12 1.12

TOTAL DESIGN MOMENTS : 3.32 33.40 REQD. STEEL AREA : 1822.71 Sq.mm. MAIN REINFORCEMENT : Provide 17 - 12 dia. (3.92%, 1922.65 Sq.mm.) (Equally distributed)

TIE REINFORCEMENT : Provide 8 mm dia. rectangular ties @ 190 mm c/c SECTION CAPACITY (KNS-MET) --------------------------

Puz : 992.70 Muz1 : 36.87 Muy1 : 36.87

INTERACTION RATIO: 1.00

============================================================================


Section 4A

4-8

Table 4A.1 Chinese Concrete Design GB50010-2002 Parameters

Parameter Default Description Name Value

FYMAIN 210 N/mm2 Yield Stress for main reinforcing

steel.

FYSEC 210 N/mm2 Yield Stress for secondary

reinforcing steel.

FC 15 N/mm2 Concrete Yield Stress.

CLEAR 25 mm 40 mm

For beam members. For column members





BRACING 0.0 BEAM DESIGN

A value of 1.0 means the effect of axial force will be taken into account for beam design.

COLUMN DESIGN

A value of 1.0 means the column is unbraced about major axis.

A value of 2.0 means the column is unbraced about minor axis.

A value of 3.0 means the column is unbraced about both axis.


Section 4A

4-9



RFACE 4.0 A value of 4.0 means longitudinal reinforcement in column is arranged equally along 4 faces.

A value of 2.0 invokes 2 faced distribution about major axis.

A value of 3.0 invokes 2 faced distribution about minor axis.




For TRACK = 0.0, output consists of reinforcement details at START, MIDDLE and END. For TRACK = 1.0, critical moments are printed in addition to TRACK 0.0 output. For TRACK = 2.0, required steel for intermediate sections defined by NSECTION are printed in addition to TRACK 1.0 output.

COLUMN DESIGN:

With TRACK = 0.0, reinforcement details are printed. With TRACK = 1.0, column interaction analysis results are printed in addition to TRACK 0.0 output. With TRACK = 2.0, a schematic interaction diagram and intermediate interaction values are printed in addition to TRACK 1.0 output.



Section 4A

4-10



ELZ 1.0 Ratio of effective length to actual length of column about major axis.

ELY 1.0 Ratio of effective length to actual length of column about minor axis.



codes.

4-11

Steel Design Per GBJ 50017-2003

4B.1 General


implementation in STAAD of the National Standard of the

People‟s Republic of China specifications for Design of Steel

Structures (GB50017-2003). The design philosophy and procedural

logistics are based on the principles of limit state design method.

Facilities are available for member selection as well as code

checking. The following sections describe the salient features of

the design approach.

Members are proportioned to resist the design loads without

exceedance of the capacities. The most economical section is

selected on the basis of the least weight criteria. The code

checking part of the program also checks the slenderness

requirements and the stability criteria. It is generally assumed that

the user will take care of the detailing requirements like flange

buckling, web crippling etc. Users are recommended to adopt the

following steps in performing the steel design:

1. Specify the geometry and factored loads. Perform the

analysis.

2. Specify the design parameter values if different from the

default values.

3. Specify whether to perform code checking or member

selection.

Section 4B


Section 4B

4-12








analysis, P-Delta analysis or Non-linear analysis may be specified.

Dynamic analysis may also be performed and the results combined

with static analysis results.






User Table facility. For more information on these facilities, r efer

to the STAAD Program Technical Reference manual.

4B.4 Built-in Chinese Steel Section Library






for these members. An example of the member property

specification in an input file is provided at the end of this section.

A complete listing of the sections available in the built -in steel


user interface.

Section 4B

4-13


I Shapes

I shaped sections are designated in the following way.

1 TO 5 15 16 TABLE ST I22B

H Shapes

H shaped sections are designated in the following way.

6 TO 8 TABLE ST HW250X250

T Shapes

T shaped sections are designated in the following way.

24 25 33 to 36 TABLE ST TM244X300

Channels

Channels are specified in the following way.

29 30 TABLE ST CH25A

Double Channels




11 TABLE D CH22B

17 TABLE D CH40C SP 0.15


Section 4B

4-14


channel CH22B with no spacing in between. Member 17 is a

double channel CH40C with a spacing of 0.15 length units between

the channels.

Angles

Two types of specifications may be used to describe an angle. The


19 TABLE ST L100X100X7



27 TABLE RA L40X25X3


25mm and a leg thickness of 3 mm. This specification may be used

when the local Z axis corresponds to the z-z axis specified in

Chapter 2. If the local Y axis corresponds to the z-z axis, type

specification "RA" (reverse angle) may be used.

Double Angles





22 TABLE LD L56X36X3

32 TABLE SD L45X28X4

20 TABLE LD L56X36X3 SP 0.15

28 TABLE SD L56X36X4 SP 0.15

Section 4B

4-15


Tubes can be assigned in 2 ways. In the first method, the

designation for the tube is as shown below. This method is meant

for tubes whose property name is available in the steel table. In

these examples, member 12 consist of a 10X6X0.3 cm size tube

section,

12 TABLE ST TUB100603.0

In the second method, tubes are specified by their dimensions. For

example,

13 TABLE ST TUBE TH 0.15 WT 0.8 DT 0.6

is a tube that has a height of 0.6 length units, width of 0.6 length

units, and a wall thickness of 0.15 length un its.


Pipes can be assigned in 2 ways. In the first method, the

designation for the pipe is as shown below. This method is meant

for pipes whose property name is available in the steel table.

21 31 TABLE ST PIP203X6.5

In the second method, pipe sections may be provided by specifying

the word PIPE followed by the outside and inside diameters of the

section. For example,

9 10 14 18 23 26 TABLE ST PIPE OD 0.6 ID

0.55

specifies a pipe with outside diameter of 0.6 length units and

inside diameter of .55 length units.


Section 4B

4-16

Sample File Containing Chinese Shapes

STAAD SPACE


ENGINEER DATE 04-Aug-05

END JOB INFORMATION

UNIT METER KN

JOINT COORDINATES

1 0 0 0; 2 4 0 0; 3 9 0 0; 4 0 0 4; 5 4 0 4; 6 0 0 8; 7 4 0 8; 8 9 0 8;

9 0 3.5 0; 10 4 3.5 0; 11 9 3.5 0; 12 0 3.5 4; 13 4 3.5 4; 14 0 3.5 8;

15 4 3.5 8; 16 9 3.5 8; 17 0 7 0; 18 4 7 0; 19 9 7 0; 20 0 7 4;

21 4 7 4; 22 0 7 8; 23 4 7 8; 24 9 7 8;

MEMBER INCIDENCES

1 1 9; 2 2 10; 3 3 11; 4 4 12; 5 5 13; 6 6 14; 7 7 15; 8 8 16; 9 9 17;

10 10 18; 11 11 19; 12 12 20; 13 13 21; 14 14 22; 15 15 23; 16 16 24;

17 9 10; 18 10 11; 19 12 13; 20 14 15; 21 15 16; 22 17 18; 23 18 19;

24 20 21; 25 22 23; 26 23 24; 27 9 12; 28 12 14; 29 10 13; 30 13 15;

31 11 16; 32 17 20; 33 20 22; 34 18 21; 35 21 23; 36 19 24;

MEMBER PROPERTY CHINESE

*I SHAPES

1 TO 5 15 16 TABLE ST I22B

*H SHAPES

6 TO 8 TABLE ST HW250X250

*T SHAPES

24 25 33 to 36 TABLE ST TM244X300

*CHANNELS

29 30 TABLE ST CH25A

*DOUBLE CHANNELS

11 TABLE D CH22B

17 TABLE D CH40C SP 0.15

*ANGLES

19 TABLE ST L100X100X7

*DOUBLE ANGLES

27 TABLE RA L40X25X3

22 TABLE LD L56X36X3

32 TABLE SD L45X28X4

20 TABLE LD L56X36X3 SP 0.15

Section 4B

4-17

28 TABLE SD L56X36X4 SP 0.15

*TUBES

12 TABLE ST TUB100603.0

13 TABLE ST TUBE TH 0.15 WT 0.8 DT 0.6

*PIPES

21 31 TABLE ST PIP203X6.5

9 10 14 18 23 26 TABLE ST PIPE OD 0.6 ID 0.55


FINISH


The basic measure of member capacities are the allowable stresses

on the member under various conditions of applied loading such as

allowable tensile stress, allowable compressive stress etc. These

depend on several factors such as cross sectional properties,

slenderness factors, unsupported width to thickness ratios and so

on. Explained here is the procedure adopted in STAAD for

calculating such capacities.

Allowable stress for Axial Tension



member is calculated on the basis of allowable tensile stresses

provided in Table 3.4.1-1 of the code. STAAD calculates the

tension capacity of a given member per this allowable stress value

and a user supplied net section factor (NSF-a default value of 1.0

is present but may be altered by changing the input value, see

Table 1) and proceeds with member selection or code checking.

Allowable stress for Axial Compression

The allowable stress for members in compression is determined

according to Table 3.4.1-1. Compressive resistance is a function of

the slenderness of the cross-section (Kl/r ratio) and the user may

control the slenderness value by modifying parameters such as


Section 4B

4-18

KY, LY, KZ and LZ. The provisions of Section 5 are used to check

the adequacy of sections in compression.

Allowable stress for Bending and Shear

Sections subjected to bending moments and shear forces are to be

designed according to the provisions of section 4. The permissible

bending compressive and tensile stresses are dependent on such

factors as outstanding legs and thickness of flanges, unsupported

length of the compression flange (UNL, defaults to member

length) etc. Shear capacities are calculated according to Table

3.4.1-1 and Section 4 and are a function of web depth, web

thickness etc. Users may use a value of 1.0 or 2.0 for the TRACK

parameter to obtain a listing of the bending and shear capacities.

Allowable stress for Combined Loading

For members experiencing combined loading (axial force, bending

and shear), applicable interaction formulas are checked at different

locations of the member for all modeled loading situations. The

procedure of Section 5 is implemented for combined axial load and

bending.

4B.6 Combined Loading



locations of the member for all modeled loading situations. The

procedure of Section 5 is implemented for combined axial load and

bending.


The user is allowed complete control over the design process

through the use of parameters mentioned in Table 4B.1 of this

chapter. These parameters communicate design decisions from the

engineer to the program.

Section 4B

4-19



the particular design requirements of an analysis, some or all of

these parameter values may have to be changed to exactly model

the physical structure. Note: Once a parameter is specified, its



Table 4B.1 Chinese Steel Design Parameters

Parameter

Name Definition

Reference

(GB50017-2003)

Default Value

Remarks

Ly

Length in local Y axis for slenderness value KL/r

- 0 Default is selected beam's length

Lz

Length in local Z axis for slenderness value KL/r

- 0 Default is selected beam's length

Dmax Maximum allowable depth

- 100 cm -

Dmin Minimum required depth - 0 cm -

Ky K value in local Y-axis, usually minor axis

- 1 -

Kz K value in local Z-axis, usually major axis

- 1 -

Nsf

Net section factor for tension members

- 1 -

Main

Flag for controlling slenderness check

- -

0 = Check for slenderness. 1 = Do not check for slenderness

Track Track parameter - 0

0 = Suppress critical member stress. 1 = Print all critical member stress. 2 = Print expanded output.


Section 4B

4-20


Parameter

Name Definition

Reference

(GB50017-2003)

Default Value

Remarks

Ratio

Permissible ratio of actual to allowable stress

- 1 -

Beam Beam parameter - 1

0 = Perform design at ends and those locations specified in the section command. 1 = Perform design at ends and 1/12th section locations along member length.

Grade Grade of steel Clause 3.4.1 1

The Following values represent the various grades of steel. Q235 - 1 Q345 - 2 Q390 - 3 Q420 - 4

Compression Allowable KL/r value in compression

- 150 -

Tension Allowable KL/r value in tension

- 300 -

Pfy

Plasticity adaptation factor Y direction

Table - 5.2.1 1.2 -

Pfz

Plasticity adaptation factor Z direction

Table - 5.2.1 1.05 -

Section 4B

4-21


Parameter

Name Definition

Reference

(GB50017-2003)

Default Value

Remarks

Sfy Stability factor for Y direction Appendix-C 1

Stability factor for axial compression members shall be selected from appendix –C based on its slenderness ratio, yield strength, classification of the section in Table 5.1.2-1 and Table 5.1.2-2

Sfz Stability factor for Z direction Appendix-C 1

Stability factor for axial compression members shall be selected from appendix –C based on its slenderness ratio, yield strength, classification of the section in Table 5.1.2-1 and Table 5.1.2-2

SBY Overall Stability factor for Y direction

Appendix-B 1 -

SBZ Overall Stability factor for Z direction

Appendix-B 0 -

4B.8 Code Checking



checked per the GB50017-2003 requirements.




beam, and the maximum moment about the major axis is used.


Section 4B

4-22

When no sections are specified and the BEAM parameter is set to

zero (default), design will be based on member start and end

forces. The code checking output labels the members as PASSed or

FAILed. In addition, the critical condition, governing load case,

location (distance from start joint) and magnitudes of the

governing forces and moments are also printed.









the user table.

Sample Input data for Steel Design

UNIT METER

PARAMETER

CODE CHINESE

NSF 0.85 ALL

GRADE 3.0 MEMBER 7

KY 1.2 MEMBER 3 4

RATIO 0.9 ALL

TRACK 1.0 ALL

CHECK CODE ALL

Section 5

European Codes

5-1

Concrete Design Per Eurocode EC2


STAAD provides a comprehensive set of national codes for the

design of concrete structures. In general, all the available codes,

including EC2, follow the same procedure for the design of the

concrete members.

The main steps in performing a design operation are:

1. Selecting the applicable load cases to be considered in the

design process.

2. Providing appropriate parameter values if different from the

default values.

3. Perform the design for the member as appropriate.

These operations can be repeated by the user any number of times

depending on the design requirements. The parameters referred to

above provide the user with the ability to allocate specific design

properties to individual members considered in the design

operation.

5A.2 Eurocode 2 (EC2)

Eurocode 2, Design of concrete structures, Part 1, General rules

and rules for buildings, provides design rules applicable to plain,

reinforced or prestressed concrete used in buildings and civil

engineering works. It is based on the limit state philosophy

common to modern standards.

Section 5A


Section 5A

5-2

The objective of this method of design is to ensure that possibility

of failure is reduced to a negligible level. This is achieved through

application of factors to both the applied loads and the material

properties. The code also provides guidelines on the global method

of analysis to be used for calculating internal member forces and

moments. STAAD provides a number of methods for analys is,

allowing Geometric Nonlinearity as well as P-Delta effects to be

considered.

5A.3 National Application Documents

Various authorities of the CEN member countries have prepared

National Application Documents to be used with EC2. These

documents provide alternative factors for loads and may also

provide supplements to the rules in EC2.

The current version of EC2 implemented in STAAD adheres to the

factors and rules provided in EC2 and has not been modified by

any National Application Documents.

5A.4 Material Properties and Load Factors

Design resistances are obtained by dividing the characteristic yield

strengths, as given in table 2.3 of EC2, by the material partial

safety factors c for concrete and s for reinforcements. The

magnitude in STAAD is 1.5 for concrete and 1.15 for

reinforcements.

Material coefficients in STAAD take the following default values

unless replaced by user's numerical values provided in the input

file.

Modulus of Elasticity E = 21.71 KN/mm2

Shear Modulus G = E / 2 (1 + v)

Poisson's Ratio v = 0.25

Unit weight = 23.56 KN/m3

Section 5A

5-3

The magnitude of design loads is dependent on F, the partial

safety factor for the action under consideration. In STAAD the

user is allowed total control in providing applicable values for the

factors and their use in various load combinations.

5A.5 Columns

Columns are designed for axial compressive loads and possible

moments at the ends of the member. If a particular load case

causes tension in the column being designed that load case is

ignored, the design proceeds with a warning message given to that

affect.

All active load cases will be considered in the design and

reinforcements are assumed symmetrically arranged in the cross

section.

The maximum reinforcement calculated after all design load cases

have been considered is then reported as the critical required area

of reinforcement.

Slender columns are also covered in the design process, the

program will make due allowance for the additional moment that

has to be considered in the design.

Please note that sway type structures are not directly covered in

the current implementation of EC2. This effect, however, can be

catered for by the P-DELTA analysis option.

5A.6 Beams


actions active load cases are scanned to create appropriate

envelopes for the design process. Maximum torsional moment is

also identified and incorporated in the design.


Section 5A

5-4

Design for flexure

Reinforcement for both positive and negative moments is

calculated on the basis of the section properties provided by the

user. If the required reinforcement exceeds the maximum

allowable then the section size is inadequate and a massage to that

effect is given in the output. Parabolic-rectangular stress

distribution for the concrete section is adopted and as moment

redistribution is not available in STAAD analysis, the limit for

N.A to depth ratio is set according to clause 2.5.3.4.2 (5) of the

code.

If required, compression reinforcement will be provided in order to

satisfy the above limits. It is important to know that beams are

designed for the flexural moment MZ only. The moment MY is not

considered in the design at all.

Design for Shear

Shear reinforcement design is based on the standard method

mentioned in clause 4.3.2.4.3 where it is assumed the notional

strut inclination is constant. Depending on the shear distribution

within the member it may be possible that nominal shear

reinforcement will be sufficient to cater for the design shear

forces. If this is not the case an attempt is made to identify regions

where nominal reinforcement is insufficient and appropriate

reinforcement is then calculated to cover the excess design shear

force.

The maximum shear force that can be carried without crushing the

concrete is also checked and if exceeded, a message to revise the

section size is given in the output file.

Design for Torsion

Torsional moments arising as a result of equilibrium requirements

need to be designed for at the ultimate limit state. Reinforcement

for torsional moments consists of stirrups combined with

longitudinal bars. The combined magnitude of shear stress arising

from shear forces and torsional moments are checked in order to

establish whether the section size is adequate. If section size is

Section 5A

5-5

inadequate a massage is given in the output file, otherwise, full

design is carried out and both shear links and longitudinal bars

required are calculated and, where necessary, links are combined

with the shear force links and printed in a tabulated manner in the

output file.

5A.7 Slabs

Slabs can only be designed for if finite elements are used to

represent them in the model of the structure. In the main the

design follows the same procedure as for flexure except that shear

forces are assumed to be resisted without the provision of shear

reinforcements. In cases where this may not be the case users must

ensure that necessary checks are carried out. The output for the

slab design refers to longitudinal reinforcements, which coincides

with the local x direction of the element, and, transverse

reinforcement, which coincides with the local y direction of the

element. Also, reference is made to 'TOP' and BOTT'

reinforcement which relates to the element's 'TOP' and 'BOTTOM'

as determined from the connectivity of the element. This may not

coincide with the slab's actual top and bottom and, if desired, users

must ensure this through the numbering scheme of the elements

(see figure 1.13 in the STAAD Technical Reference Manual). The

design of the slab considers a fixed bar size of 16mm in both

directions with the longitudinal bar being the layer closest to the

slab exterior faces.


Design parameters communicate specific design decisions to the

program. They are set to default values to begin with and may be

altered to suite the particular structure. Depending on the model

being designed, the user may have to change some or all of the

parameter default values. Some parameters are unit dependent and

when altered, the new setting must be compatible with the active

"unit" specification. Table 5A.1 lists all the relevant EC2

parameters together with description and default values.


Section 5A

5-6

Note: Once a parameter is specified, its value stays at that speci fied


all codes.

Table 5A.1 – Concrete Design Parameters-EC2


Name Value

FYMAIN *460 N/mm2 Yield Stress for main reinforcement (For slabs, it is for reinforcement in both directions)

FYSEC *460N/mm2 Yield Stress for secondary reinforcement. Applicable to shear bars in beams

FC * 30N/mm2 Concrete Yield Stress / cube strength

MINMAIN 8mm Minimum main reinforcement bar size Acceptable bar sizes: 6 8 10 12 16 20 25 32 40 50


CLEAR * 20mm Clearance of reinforcement measured from concrete surface to closest bar perimeter.


SFACE *0.0 Face of support location at start of beam. (Only applicable for shear - use MEMBER OFFSET for bending )

EFACE *0.0 Face of support location at end of beam. (NOTE: Both SFACE & EFACE must be positive numbers.)

TRACK 0.0 0.0 = Critical Moment will not be printed with beam design report. Column design gives no detailed results.


2.0 = Output of TRACK 1.0 List of design sag/hog moments and corresponding required steel area at each section of member

MMAG 1.0 Factor by which column design moments are magnified

Section 5A

5-7

NSECTION 10 Number of equally-spaced sections to be considered in finding critical moment for beam design. The upper limit is 20.



BRACE 0.0 0.0 = Column braced in both directions. 1.0 = Column unbraced about local Z direction

only 2.0 = Column unbraced about local Y

direction only 3.0 = Column unbraced in both Y and Z

directions




-500 = Orthogonal reinforcement layout with Mxy used to calculate WOOD & ARMER moments for design.

A = Skew angle considered in WOOD & ARMER equations where A is the angle in degrees.

SERV 0.0 0.0 = No serviceability check performed. 1.0 = Perform serviceability check for beams

as if they were continuous. 2.0 = Perform serviceability check for beams

as if they were simply supported. 3.0 = Perform serviceability check for beams

as if they were cantilever beams. * Provided in current unit system


Section 5A

5-8

5-9

Steel Design Per Eurocode EC3

5B.1 General Description

Introduction


specification Eurocode 3: Design of steel structures – part 1-1:

General Rules and rules for buildings has been implemented.

Two versions of the code are currently implemented, the EC3_94/1

and BS EN 1993-1-1:2005.

To access the EC3_94/1 edition, specify the commands:

PARAMETERS CODE

EC3

Or

PARAMETERS

CODE

EURO

To access the BS EN 1993-1-1:2005 edition, specify the

commands:

PARAMETERS

CODE

EC3 BS

Section 5B


Section 5B

5-10

The main steps in performing a design operation are:

1. Selecting the applicable load cases to be

considered in the design process.

2. Providing appropriate parameter values if different

from the default values.

3. Specify whether to perform code-checking and/or

member selection.

These operations can be repeated by the user any number of times

depending on the design requirements.

The parameters, referred to above, provide the user with the

ability to allocate specific design properties to individual members

considered in the design operation.

Eurocode (EC3)

Eurocode 3, Design of steel structures, Part 1.1 General rules and

rules for buildings (EC3) provides design rules applicable to

structural steel used in buildings and civil engineering works. It is

based on the limit states philosophy common to modern standards.

The objective of this method of design is to ensure that possibility

of failure is reduced to a negligible level. This is achieved through

application of factors to both the applied loads and the material

properties.

The code also provides guidelines on the global method of analysis

to be used for calculating internal member forces and moments.

STAAD uses the elastic method of analysis which may be used in

all cases. Also there are three types of framing referred to in EC3.

These are “Simple”, “Continuous”, and “Semi -continuous” which

reflect the ability of the joints in developing moments. In STAAD,

only “Simple” and “Continuous” joint types can be assumed when

carrying out global analysis.

Section 5B

5-11

Axes convention in STAAD and EC3

By default, STAAD defines the major axis of the cross-section as

zz and the minor axis as yy. A special case where zz is the minor

axis and yy is the major axis is available if the “SET Z UP”

command is used and is discussed in the Technical Reference

Manual. The longitudinal axis of the member is defined as x and

joins the start joint of the member to the end with the same

positive direction.

EC3, however, defines the principal cross-section axes in reverse

to that of STAAD, but the longitudinal axis is defined in the same

way. Both of these axes definitions follow the orthogonal right

hand rule. See figure below.

Users must bear this difference in mind when examining the code-

check output from STAAD.

STAAD EC3

Figure 1 Axes Convention in STAAD and EC3.

National Application Documents

Various authorities of the CEN member countries have prepared

National Application Documents to be used wi th EC3. These

documents provide alternative factors for loads and may also

provide supplements to the rules in EC3.

The current version of EC3 implemented in STAAD adheres to the

factors and rules provided in EC3 and have not been modified by

any National Application Documents.


Section 5B

5-12

Section Classification

The occurrence of local buckling of the compression elements of a

cross-section prevents the development of full section capacity. It

is therefore imperative to establish this possibility prior to

determining the section capacities. Cross sections are classified in

accordance with their geometrical properties and the stress pattern

on the compression elements. For each load case considered in the

design process, STAAD determines the section class and calculates

the capacities accordingly.

Material Properties and Load Factors

Design resistances are obtained by dividing the characteristic yield

strength, as given in table 3.1, by the material partial safety factor

gm. The magnitude of gm in STAAD is 1.1 which is applicable to

all section types.

Material coefficients in STAAD take the following default values

unless replaced by user‟s numerical values provided in the input

file.

Modulus of Elasticity E = 205 N/mm2

Shear Modulus G = E / 2 (1+v)

Poisson‟s Ratio v = 0.3

Unit weight r = 76.8 KN/m3

The magnitude of design loads is dependent on g f, the partial

safety factor for the action under consideration. In STAAD, the

user is allowed total control in providing applicable values for the

factors and their use in various load combinations.

Axially Loaded Members

For members subject to tension loads only, tension capacity is

calculated based on yield strength, material factor g m and cross-

sectional area of the member with possible reduction due to bolt

holes. When bolt holes need to be considered in the capacity

calculations, the value used for gm is 1.2 and the yield strength is

replaced with the ultimate tensile strength of the material. The

Section 5B

5-13

tension capacity is then taken as the smaller of the full section

capacity and the reduced one.

For members subject to compression only, cross-section resistance

as well as buckling resistance must be checked. The latter is often

more critical as it is influenced by a number of factors including

the section type and member unbraced length.

Beams

The main requirement for a beam is to have sufficient cross -

section resistance to the applied bending moment and shear force.

Also the possibility of lateral-torsional buckling must be taken

into consideration when the full length of the member is not

laterally restrained.

The bending capacity is primarily a function of the section type

and the material yield strength. There are four classes of cross -

sections defined in EC3. Class 1 and 2 sections can both attain full

plastic capacity with the exception that the class 2 sections cannot

sustain sufficient rotation required for plastic analysis of the

model.

Class 3 sections, due to local buckling, cannot develop plastic

moment capacity and the yield stress is limited to the extreme

compression fiber of the section. The elastic section modulus is

used to determine the moment capacity.

Class 4 sections do suffer from local buckling and explicit

allowance must be made for the reduction in section properties

before the moment capacity can be determined. Further, because of

interaction between shear force and bending moment, the moment

resistance of the cross-section may be reduced. This, however,

does not occur unless the value of applied shear forces exceeds

50% of the plastic shear capacity of the section. In such cases the

web is assumed to resist the applied shear force as well as

contributing towards the moment resistance of the cross-section.


Section 5B

5-14

The plastic shear capacity is calculated using the appropriate shear

area for the section and the yield strength in shear, taken as3

fy.

As mentioned earlier, lateral-torsional buckling must also be

considered whenever the full length of the member is not laterally

restrained. The buckling capacity is dependent on the section type

as well as the unrestrained length, restraint conditions and type of

applied loading.


The bending resistance of members subject to coexistent axial load

is reduced by the presence of the axial load. The presence of large

shear, as mentioned above, can also reduce the bending resistance

of the section under consideration.

If the shear load is large enough to cause a reduction in bending

resistance, then the reduction due to shear has to be taken into

account before calculating the effect of the axial load on the

bending resistance of the section.

Generally, EC3 requires checking cross-section resistance for local

capacity and also checking the overall buckling capacity of the

member. In the case of members subject to axial tension and

bending, there is provision to take the stabilizing effect of the

tension load into consideration. This is achieved by modifying the

extreme compression fiber stress and calculating an effective

applied moment for the section. This is then checked against the

lateral-torsional buckling resistance of the section.


Introduction



altered to suite the particular structure.

Section 5B

5-15

Depending on the model being designed, the user may have to

change some or all of the parameter default values. Some

parameters are unit dependent and when altered, the new setting

must be compatible with the active “unit” specification.

Table 5B.1 lists all the relevant EC3 parameters together with

description and default values. Note: Once a parameter is

specified, its value stays at that specified number till it is

specified again. This is the way STAAD works for all codes.

Table 5B.1 – Steel Design Parameters EC3

Parameter Default Definition

Name Value

KY 1.0 K factor in local y axis. KZ 1.0 K factor in local z axis. LY Member Length Compression length in local y axis,

Slenderness ratio = (KY)*(LY)/(Ryy) LZ Member Length Compression length in local z axis,

Slenderness ratio = (KZ)*(LZ)/(Rzz) UNL Member Length Unrestraint length of member used in

calculating the lateral-torsional resistance moment of the member.

PY Yield Strength The yield strength default value is set based on the default value of the “SGR” parameter.

NSF 1.0 Net tension factor for tension capacity calculation.

SGR 0.0 Steel grade as per table 3.1 in EC3. 0.0 = Fe 360 1.0 = Fe 430 2.0 = Fe 510

SBLT 0.0 Indicates if the section is rolled or built-up. 0.0 = Rolled 1.0 = Built-up.

CMM 1.0 Indicates type of loading on member. Can take a value from 1 to 6. Refer to Table 5B.2 for more information on its use.

CMN 1.0 Indicates the level of End-Restraint. 1.0 1.0 = No fixity 0.5 = Full fixity

0.7 = One end free and other end fixed


Section 5B

5-16

Table 5B.1 – Steel Design Parameters EC3

Parameter Default Definition

Name Value

DMAX 100.0 cm Maximum allowable depth for the member. DMIN 0 Minimum required depth for the member. RATIO 1 Permissible ratio of loading to capacity. BEAM 0 Indicates the number of sections to be

checked for during the design. 0 = Check the end sections only or the locations

specified by the SECTION command. 1 = Consider 13 sections along the member and

select the maximum Mz location for the design check.

2 = Same as BEAM = 1.0 but checks the end sections of the member as well.

3 = Consider 13 sections along the member and design check every section.

CODE Undefined User must specify EC3. TRACK 0 Controls the level of descriptivity of output.

0 = Minimum 1 = Intermediate 2 = Maximum 4 = option 4 for performing a deflection check

UNF 1.0 Unsupported buckling length as a factor of the beam length

LEG 0.0 Connection type LVV Maximum of Lyy and

Lzz (Lyy is a term used

by BS5950)

Buckling length for angle about its principle axis

FU Ultimate tensile strength of steel DFF None

(Mandatory for deflection check)

Deflection limit


Joint No. denoting starting point for calculation of "Deflection Length"

DJ2 End Joint of member Joint No. denoting end point for calculation of "Deflection Length"

Section 5B

5-17

Notes:

1. LEG - Table 25 BS5950 for Fastener Control

The slenderness of single and double angle, channel and tee

sections are specified in BS 5950 table 25 depending on the

connection provided at the end of the member. To define the

appropriate connection, a LEG parameter should be assigned

to the member.

The following table indicates the value of the LEG parameter

required to match the BS5950 connection definition: -

Clause LEG

4.7.10.2

Single Angle


long leg 3.0


long leg 2.0

4.7.10.3

Double Angle


long leg 7.0


long leg 6.0

(c) - 2 bolts long leg 1.0

short leg 5.0

(d) - 1 bolt long leg 0.0

short leg 4.0

4.7.10.4

Channels



4.7.10.5

Tee Sections




Section 5B

5-18

For single angles, the slenderness is calculated for the

geometric axes, a-a and b-b as well as the weak v-v axis. The

effective lengths of the geometric axes are defined as:-

La = KY * KY

Lb = KZ * LZ

The slenderness calculated for the v-v axis is then used to

calculate the compression strength pc for the weaker principal

axis (z-z for ST angles or y-y for RA specified angles). The

maximum slenderness of the a-a and b-b axes is used to

calculate the compression strength p c for the stronger principal

axis.

Alternatively for single angles where the connection is not

known or Table 25 is not appropriate, by setting the LEG

parameter to 10, slenderness is calculated for the two principal

axes y-y and z-z only. The LVV parameter is not used.

For double angles, the LVV parameter is available to comply

with note 5 in table 25. In addition, if using double angles from

user tables, (Technical Reference Manual section 5.19) an

eleventh value, rvv, should be supplied at the end of the ten

existing values corresponding to the radius of gyration of the

single angle making up the pair.

2. BEAM

Ensure that the “BEAM” parameter is set to either 1 or 2 while

performing code checking for members susceptible to Lateral -

Torsional Buckling.

Section 5B

5-19

Table 5B.2


A design performed to the new Eurocode 3 standard is displayed in

the output file (*.ANL) with the following header: -

STAAD.PRO CODE CHECKING - (BS EN 1993-1-1:2005) **************************

PROGRAM CODE REVISION V1.1 BS_EC3_2005/1


Section 5B

5-20

The equivalent header for a code check (or member selection) to

the older standard is displayed thus:-

STAAD.PRO CODE CHECKING - (DD ENV) ***********************

PROGRAM CODE REVISION V1.14_EC3_94/1

5B.4 Worked Examples

Example 1: Restrained simply supported beam.

The figure below shows a simply supported beam spanning 7

meters and assumed to be fully restrained laterally. Fe 430 steel is

assumed and the beam will be checked to the clauses of EC3

currently implemented in STAAD.

Unfactored Loading

Permanent Load:

UDL including selfweight assume 20 KN/m

Variable Load:

UDL load assume 25 KN/m

Partial safety factor for permanent load (ULS) 1.35

Partial safety factor for variable load (ULS) 1.5

Factored Load: 1.35 X 15 + 1.5 X 25 = 64.5 KN/m

Section 5B

5-21

64.5 KN/m

Try 457 X 191 X 82UB.

h = 460.2 mm d = 407.9mm tw = 9.9 mm

b = 191.3 mm tf = 16.0 mm A = 104.5cm2

ly = 37103 cm4 Wpl.y = 1833 cm3 Av = 48.13 cm2

Grade Fe 430 Fy = 275 N/mm2


Outstand Flanges in Compression, limit for rolled section

c/t = 10e = 9.2

c/t ratio for the selected section is 95.65/16 = 5.9 < 9.2

Flange is therefore a class 1 element.

Web with N.A. at mid depth, limit for rolled section

d/tw = 72e = 66.6

d/ tw ratio for the selected section is 407.9/9.9 = 41.2 < 66.6

Web is therefore a class 1 element.

Section is class 1


Section 5B

5-22

Shear Resistance

Maximum design shear force (64.5 X 7) / 2 = 225.7 KN

Plastic shear resistance Vpl.Rd = (Av / gM0) (fy / 3 )

= (4813 / 1.1) (275 / 1.732) / 1000

= 694.7 KN

Maximum design shear force = 225.7 KN < 694.7 KN

Therefore shear resistance is satisfactory.

Moment Resistance

Maximum design moment at mid-span of beam

(wl2 / 8) = 395 Knm

Maximum resistance of section Mc.Rd = ( Wpl.yfy) / gM0

= (1833 X 103 X 275) / (1.1 X 106)

= 458.2KNm


As it is assumed that the full length of member is restrained

laterally there is no need to check for Lateral Torsional Buckling

of the member.

Maximum design moment = 395 KNm < 458.2 KNm

Therefore moment resistance is satisfactory.

457 X 191 X 82 UB In Fe 430 Steel is satisfactory.

Section 5B

5-23

Example 2: Unrestrained simply supported beam.

Figure 2 shows a simply supported beam spanning 5 meters and

assumed to be laterally unrestrained. Fe 430 steel is assumed and

the beam will be checked to the clauses of EC3 currently

implemented in STAAD.

5m

Unfactored Loading

Permanent Load:

UDL including selfweight assume 15 KN/m

Variable Load:

UDL load assume 20 KN/m

Partial safety factor for permanent load (ULS) 1.35

Partial safety factor for variable load (ULS) 1.5

Factored Load: 1.35 X 15 + 1.5 X 20 = 50.3 KN/m

50.3 KN/m

5m


Section 5B

5-24

Try 457 X 191 X 82 UB.

h = 460.2 mm d = 407.9 mm tw = 9.9 mm

b = 191.3 mm tf = 16.0 mm A = 104.5 cm2

ly = 37103cm4 Wpl.y = 1833cm3 Av = 48.13cm2

Grade Fe 430fy = 275 N/mm2


Outstand Flanges in compression, limit for rolled section

c/t = 10e = 9.2




d/tw = 72e = 66.6



Shear Resistance

Maximum design shear force (50.3 X 5) / 2 = 120.8 KN

Plastic shear resistance Vpl.Rd = (Av / gM0) (fy / 3 )

= (4813 / 1.1) (275 / 1.732) / 1000

= 694.7 KN

Maximum design shear force = 120.8 KN < 694.7 KN

Therefore shear resistance is satisfactory.

Section is class 1

Section 5B

5-25

Moment Resistance

Maximum design moment at mid-span of beam

(wl2 / 8) = 157.2 KNm

Maximum resistance of section Mc.Rd = ( Wpl.yfy) / gM0

= (1833 X 103 X 275) / (1.1 X 106)

= 458.2KNm


Buckling resistance moment Mb.Rd = XLTbwWPl.yfy / gM1

bw = 1 for Class 1 or Class 2 sections.

XLT = 0.5

LT2

LT2

LT ]l[ff

1

fLT = 0.5 [1 + aLT( lLT – 0.2 ) + l2LT ]

aLT = 0.21 for rolled sections.

lLT = [ lLT / l1 ] [bw]0.5

l1 = 93.9e

lLT is the geometrical slenderness ratio for lateral -torsional

buckling.

lLT = /25.66])(L/a[1)(C

L/i

2LT

0.51

LT

aLT = ( Iw / l t ) 0.5

Maximum design moment = 157.2 KNm < 458.2 KNm

Therefore moment resistance is satisfactory.


Section 5B

5-26

lw = lzhs2 / 4

hs = h - tf

iLT = [lzIw / Wpl.y2]0.25

C1 is a factor depending on transverse loading type.

For the selected section:

hs = 460.2 – 16.0 = 444.2 mm

lw = 1871 X 44.422 / 4 = 922934.6 cm6

iLT = [1871 X 922934.6 / (18332) ]0.25 = 4.76 cm

aLT = ( 922934.6 / 69.2 ) 0.5 = 115.4 cm

C1 = 1.132 (From EC3 Table F.1.2)

lLT = 0.2520.5 /25.66])(500/115.4[11.132

500/4.76

= 86.06

l1 = 93.9 (235 / 275)0.5 86.8

lLT = 86.06 / 86.8 0.99

fLT = 0.5 [1 + 0.21 (0.99 – 0.2) + 0.992] 1.07

XLT = 1 / { 1.07 + [ 1.072 – 0.992 ] 0.5} 0.67

Mb.Rd = 0.67 X 1 X 1833 X 103 X 275 / 1.1 X 106

Mb.Rd = 307.0 KNm

Maximum design moment = 157.2 KNm < 307.0 KNm

Therefore buckling resistance moment is satisfactory.

Section 5B

5-27

Example 3: Axially Loaded Column.

Figure 3 shows a pinned end column 5m long subject to a factored

load of 3500 kN. Fe 430 steel is assumed and the column will be

checked to the clauses of EC3 currently implemented in STAAD.

3500 KN

5m

3500 KN

Try 305 X 305 X 158 UC

h = 327.2 mm d = 246.6 mm tw = 15.7 mm

b = 310.6 mm tf = 25.0 mm A = 210.2 cm2

iy = 13.9 cm iz = 7.89 cm fy = 275 N/ mm2


Outstand flanges in compression, limit for rolled section

c/t = 10e = 9.2




Section 5B

5-28


d/tw = 33e = 30.5



Compressive resistance

Design compression resistance of the cross-section,

Nc.Rd = ( Afy) / gM0

Nc.Rd = ( 210.2 X 102 X 275 ) / ( 1.1 X 103 )

Nc.Rd = 5255 KN

Buckling resistance

The design buckling resistance of the member Nb.Rd = XbAAfy /

gM0

bA = 1 for class 1, 2 or 3 cross-sections.

X is a reduction factor for the relevant buckling mode.

X =

5.02_

2 ]lf[f

1

f = 0.5 [ 1 + a (_

l – 0.2) +

2_

l ]

a is an imperfection factor.

_

l = [ l / l1 ] [ bA ]0.5

l is the slenderness for the relevant buckling mode.

Section is class 1

Applied design load NSd = 3500 KN < 5255

Therefore compression resistance is satisfactory .

Section 5B

5-29

l1 = 93.9 e

From table 5.5.3 for buckling about y-y-axis, a is 0.34.

From table 5.5.3 for buckling about z-z axis, a is 0.49.

ly = 500 / 13.9

ly = 35.97

lz = 500 / 7.89

lz = 63.37

Consider buckling about the y-y axis.

_

l y = [ ly / l1] [bA]0.5

l1 = 93.9 X 0.924 = 86.8

_

l y = [35.9 / 86.8 ] = 0.41

fy = 0.5 [1 + ay (_

l y – 0.2) + l2y]

fy = 0.5 [1 + 0.34 (0.41 – 0.2) + 0.412]

fy = 0.62

Xy =

0.5y

2_

y2

y ]l[ff

1

= 0.522 ]0.41[0.620.62

1

Xy = 0.92 but cannot be greater than 1, therefore Xy = 0.92.

Nb.Rdy = XyAfy / gM0 = (0.92 X 275 X 201.2 X 102) / (1.1 X 103)

= 4627KN


Section 5B

5-30

Consider buckling about the z-z axis.

_

l z = [ lz / l1] [bA]0.5

l1 = 93.9 X 0.924 = 86.8

_

l z = [63.37 / 86.8 ] = 0.73

fz = 0.5 [1 + az (_

l z – 0.2) +

2_

l z]

fz = 0.5 [1 + 0.49 (0.73 – 0.2) + 0.732]

fz = 0.89

Xz =

5.0z

2_

z2

z ]lf[f

1

= 0.522 ]0.73[0.890.89

1

Xz = 0.71 but cannot be greater than 1, therefore X z = 0.71.

Nb.Rdz = XzAfz / gM0 = (0.71 X 275 X 201.2 X 102) / (1.1 X 103)

= 3571KN

3400 KN design load is less than 3571 KN, therefore section is

satisfactory.

Section 5B

5-31

Example 4: Column subject to axial load and

bending

The figure below shows a pinned end column 5m long subject to a

factored load of 1500 KN and factored bending moment of 250

KNm about the major axis. Fe 430 steel is assumed and the column

will be checked to the clauses of EC3 currently implemented in

STAAD.

Try 305 X 305 X 137 UC

h = 320.5 mm d = 246.6 mm tw = 13.8 mm

b = 308.7mm tf = 21.7 mm A = 174.6cm2

Wpl.y = 2298cm3 Wel.y= 2049 cm3 Av = 50.6 cm2

iy = 13.7 cm iz = 7.82 cm fy = 275 N/mm2


Section 5B

5-32

Section classification

Shear Resistance

Maximum design shear force 250 / 5 = 50 KN

Plastic shear resistance Vpl.Rd = ( Av / gM0 ) ( fy / 3 )

= (5060 / 1.1) (275 / 1.732) / 1000

= 730 KN

Moment Resistance

Design bending moment must not exceed the reduced plastic

resistance moment of the section given by the following equations.

MNy.Rd = Mpl.y.Rd ( 1 – n ) / ( 1 – 0.5 a )

a = ( A – 2btf ) / A but „a‟ must not exceed 0.5.

n = Nsd / Npl.Rd

If „n‟ does not exceed „a‟ then MNy.Rd = Mpl.y.Rd

a = ( 17460 – 2 X 308.7 X 21.7 ) / 17460

a = 0.232

Npl.Rd = ( 275 X 17460 ) ( 1.1 X 1000 ) = 4365 KN

n = 1500 / 4365 = 0.343

Section by inspection is class 1.

Design shear force is less than 730 KN. Shear resistance is

satisfactory.

Section 5B

5-33

Mpl.y.Rd = ( 275 X 2298 ) / ( 1.1 X 1000 ) = 574.5 KN

MNy.Rd = 574.5 ( 1 – 0.343 ) / ( 1 – 0.5 X 0.232 )

MNy.Rd = 426.97 KNm

Flexural Buckling and Bending Check

Members subject to axial load and bending must satisfy:

/gM1AfX

N

ymin

sd + /gM1fW

MK

ypl.y

y.sdy 1

Ky = 1 - yy

sdy

AfX

Nm but Ky 1.5

my = _

l y (2bMy – 4) + el.y

el.ypl.y

W

WW but my 0.90

Xmin is the lesser of Xy and Xz, where Xy and Xz are reduction

factors as calculated in the previous example.

bMy is equivalent moment factor for flexural buckling.

From Figure 5.5.3 in EC3,

bMy = 1.8 – 0.7 y but in this example, y = 0.0

bMy = 1.8

The design bending moment is less than the reduced moment

capacity. The section therefore has sufficient moment resistance.


Section 5B

5-34

Consider buckling about the y-y axis.

_

l y = [ ly / l1] [bA]0.5

bA = 1.0 for class 1 sections.

l1 = 93.9 X 0.924 = 86.8

ly = [500 / 13.7 ] = 36.5

_

l y = [36.5 / 86.8 ] = 0.42

fy = 0.5 [1 + ay (_

l y – 0.2) + l2y]

fy = 0.5 [1 + 0.34 (0.42 – 0.2) + 0.422]

fy = 0.62

Xy = 0.5

y2

y2

y ]l[ff

1

=

0.522 ]0.42[0.620.62

1

Xy = 0.93 but 1, therefore Xy = 0.93.

Consider buckling about the z-z axis.

_

l z = [ lz / l1] [bA]0.5 bA = 1.0 for class 1 sections.

l1 = 93.9 X 0.924 = 86.8

lz = [500 / 7.82 ] = 63.9

_

l z = [63.9 / 86.8] = 0.73

fz = 0.5 [1 + az (_

l z – 0.2) + _

l 2z]

fz = 0.5 [1 + 0.49 (0.73 – 0.2) + 0.732]

fz = 0.89

Section 5B

5-35

Xz =

0.5z

2_

z2

z ]l[ff

1

= 0.522 ]0.73[0.890.89

1

Xz = 0.71 but 1, therefore Xz = 0.71.

Xmin is therefore 0.71.

_

l y = 0.42

my = 0.42 (2 X 1.8 – 4) + 2049

20492298 = - 0.046

Ky = 1 - X2750.93X17.46

0.046X1500 = 1.015 1.5

/gM1AfX

N

ymin

sd + /gM1fW

MK

ypl.y

y.sdy 1

X275/1.10.71X17.46

1500 +

1.12.298X275/

1.015X250 = 0.92 1

Members for which lateral-torsional buckling is a potential

problem must also satisfy:

/gM1AfX

N

yz

sd + /gM1fWX

MK

ypl.yLT

y.sdLT 1

KLT = 1 -

yz

sdLT

AfX

Nm but KLT 1

mLT = 0.15 lzbM.LT – 0.15, but mLT 0.90

Using the equations used in Example 2, we have the following.


Section 5B

5-36

For the selected selection:

iLT = 8.33 cm

aLT = 97.6 cm

C1 = 1.879 (From EC3 Table F.1.2)

lLT = 0.2520.5 /25.66](500/97.6)[11.879

500/8.33

= 36.71

l1 = 93.9 (235 / 275)0.5 = 86.8

lLT = 36.71 / 86.8 = 0.42

fLT = 0.5 [ 1 + 0.21 (0.42 – 0.2) + 0.422 ] = 0.61

XLT = 1 / { 0.61 + [ 0.612 – 0.422 ]0.5 } = 0.95

bMLT = 1.8

lz = 0.73

mLT = 0.15 X 0.73 X 1.8 – 0.15 = 0.047

KLT = 1 - X2750.71X17.46

0.047X1500 = 0.98

/gM1AfX

N

yz

sd + /gM1fWX

MK

ypl.yLT

y.sdLT 1

X275/1.10.71X17.46

1500 +

X275/1.10.95X2.298

0.98X250 = 0.932

305X305X137UC is therefore satisfactory.

Section 5B

5-37

5B.5 User’s Examples

Example 1.

The following input file is for the single beam in example 1. Only

code check related output is enclosed.

STAAD PLANE INPUT FILE FOR EX.1 IN THE EC3 MANUAL.

INPUT WIDTH 79

UNIT METER KNS

JOINT COORDINATES 1 0.000 0.000 0.000

2 5.000 0.000 0.000

MEMBER INCIDENCES

1 1 2

MEMBER PROPERTY BRITISH

1 TABLE ST UB457X191X82

CONSTANTS

E STEEL ALL

SUPPORTS

1 PINNED

2 FIXED BUT FX MZ

LOAD 1 MEMBER LOAD

1 UNI GY-20.0

LOAD 2

MEMBER LOAD

1 UNI GY -25.0

LOAD COMBINATION 3

1 1.35 2 1.5

PERFORM ANALYSIS

LOAD LIST 3

PARAMETER

CODE EC3 UNL 0.0 ALL

BEAM 2.0 ALL

TRACK 2 .ALL

SGR 1 .ALL

CHECK CODE ALL

FINISH


Section 5B

5-38

Section 5B

5-39

Example 2.

The following input file is for the beam in example 2. Only code

check related output is enclosed.

STAAD PLANE INPUT FILE FOR EXAMPLE 2

INPUT WIDTH 79

UNIT METER KNS

JOINT COORDINATES

1 0.000 0.000 0.000 2 5.000 0.000 0.000

MEMBER INCIDENCES

1 1 2

MEMBER PROPERTY BRITISH

1 TABLE ST UB457X191X82

CONSTANTS

E STEEL ALL

SUPPORTS

1 PINNED

2 FIXED BUT FX MZ

LOAD 1

MEMBER LOAD 1 UNI GY -15.0

LOAD 2

MEMBER LOAD

1 UNI GY -20.0

LOAD COMBINATION 3

1 1.35 2 1.5

PERFORM ANALYSIS

LOAD LIST 3

PARAMETER

CODE EC3

BEAM 2.0 ALL TRACK 2. ALL

SGR 1. ALL

CHECK CODE ALL

FINISH


Section 5B

5-40

Section 5B

5-41

Example 3.

The following input file is for the simple column in example 3.

Only code check related output is enclosed.

STAAD PLANE INPUT FILE FOR EXAMPLE 3.

UNIT METER KNS

JOINT COORDINATES

1 0 0 0

2 0 5 0 MEMBER INCIDENCES

1 1 2

MEMBER PROPERTIES BRITISH

1 TA ST UC305X305X158

CONSTANTS

E STEEL ALL

SUPPORT

1 FIXED

LOAD 1

JOINT LOAD

2 FY -3500

PERFORM ANALYSIS PARAMETERS

CODE EC3

TRACK 2.0 ALL

SGR 1. ALL

CHECK CODE ALL

FINISH


Section 5B

5-42

Section 5B

5-43

Example 4.

The following input file is for the column in example 4. Only code

check related output is enclosed.

STAAD PLANE INPUT FILE FOR EXAMPLE 4.

UNIT METER KNS

JOINT COORDINATES

1 0 0 0

2 0 5 0 MEMBER INCIDENCES

1 1 2

MEMBER PROPERTIES BRITISH

1 TA ST UC305X305X137

CONSTANTS

E STEEL ALL

SUPPORT

1 PINNED

2 FIXED BUT FY MZ

LOAD 1

JOINT LOAD

2 FY -1500 2 MZ 250

PERFORM ANALYSIS

PARAMETERS

CODE EC3

BEAM 2.0 ALL

TRACK 2.0 ALL

CMM 6

SGR 1.0 ALL

CHECK CODE ALL

FINISH


Section 5B

5-44

5-45

Timber Design Per EC 5: Part 1-1.

(BS EN 1995-1-1:2004)


The Timber Design facility as per EC5 in STAAD is based on the

European Standard Eurocode 5: Design of Timber Structures - Part

1-1 - General - Common rules and rules for buildings. Principles

of Limit States Design of Timber Structures are adopted as

specified in the code.

The application is limited to the PRISMATIC rectangular shapes

only. There is no Eurocode-specific timber section database /

library consisting of pre-defined shapes for analysis or for design.

The feature of member selection is thus not applicable to this code.

The design philosophy of this specification is based on the concept

of limit state design. Structures are designed and proportioned

taking into consideration the limit states at which they would

become unfit for their intended use. Two major categories of limit-

state are recognized - ultimate and serviceability. The primary

considerations in ultimate limit state design are strength and

stability, while that in serviceability is deflection. Appropriate

load and resistance factors are used so that a uniform reliability is

achieved for all timber structures under various loading conditions

and at the same time the chances of limits being surpassed are

acceptably remote.







Section 5C


Section 5C

5-46



criteria.


implementation of EC 5. A detailed description of the design

process along with its underlying concepts and assumptions is

available in the specification document.

Axes convention in STAAD and EC5

STAAD defines the major axis of the cross-section as zz and the

minor axis as yy. The longitudinal axis of the member is defined

as x and joins the start joint of the member to the end with the

same positive direction.

EC5, however, defines the principal cross-section axes in reverse

to that of STAAD, but the longitudinal axis is defined in the same

way. Both of these axes definitions follow the orthogonal right

hand rule. See figure 1 below:

y z

z z y y

y z

STAAD EC5

Figure 1 Axes convention in STAAD and EC5

Section 5C

5-47

Determination of Factors

(A) Kmod – Modification factor taking into account of Load-

duration (LDC) and Moisture-content (Service Class -

SCL). Reference Table 3.1 of EC-5-2004.

For “Solid Timber”, the values are incorporated in the

program.

(B) m – Partial factor for Material Property values.

Reference Table 2.3 of EC-5-2004.

For “Solid Timber”, the value of m (= 1.3) is

incorporated in the program.

(C) Kh – Size Factor.

For members, subjected to tension, whose maximum c/s

dimension is less than the reference width in tension the

characteristic strength in tension (ft0k) is to be increased

by the factor Kh.

For members, subjected to bending, whose depth is less

than reference depth in bending, the characteristic strength

in bending (fmk) is to be increased by the factor Kh.

As per clause 3.2(3) of EC 5- 2004, for rectangular solid

timber with a characteristic timber density k 700 kg/m3

the reference depth in bending or the reference width

(maximum cross-sectional dimension) is 150 mm.

The value of Kh = Minimum of {(150/h) 0.2 and 1.3) for

such solid timber is incorporated in the software. Please

refer clause numbers 3.3 and 3.4 for the value of Kh for

Glued laminated timber and Laminated veener lumber

respectively.


Section 5C

5-48

(D) KC90 – Factor taking into account the load

configuration, possibility of splitting and degree of

compressive deformation.

For members, subjected to compression, perpendicular to

the direction of grain alignment, this factor should be

taken into account. Default value of 1 is used in

STAAD.Pro. User may override the value. Please refer

clause 6.1.5 of EC-5-2004 in this regard.

(E) Km – Factor considering re-distribution of bending

stress in cross section.

For members, subjected to bending, this factor is taken

into account for stress checking. For rectangular section

the value of Km is 0.7, and this value is incorporated in

STAAD.Pro. User may override the value. Please refer

clause 6.1.6 of EC-5-2004 in this regard.

(F) Kshape – Factor depending on shape of cross section.

For members, subjected to torsional force, design torsional

stress should be less than equal design shear strength

multiplied by the factor Kshape. This factor is determined

by STAAD.Pro internally using the guidelines of clause

6.1.8 of EC-5-2004 .

Section 5C

5-49

5C.2 Analysis Methodology

Symbols Description

St0d Design tensile stress parallel (at zero degree) to grain

alignment. St90d Design tensile stress perpendicular (at 90 degrees) to

grain alignment. Sc0d Design compressive stress parallel to grain alignment. Sc90d Design compressive stress perpendicular to grain

alignment. Smzd Design bending stress about zz axis. Smyd Design bending stress about yy axis. Svd Design shear stress. Stor_d Design torsional stress.

Ft0d Design tensile strength - parallel to the grain

alignment. Ft90d Design tensile strength - perpendicular to the grain

alignment. Fc0d Design compressive strength - parallel to the grain

alignment. Fc90d Design compressive strength - perpendicular to the

grain alignment. Fmzd Design bending strength - about zz-axis. Fmyd Design bending strength - about yy-axis. Fvd Design shear strength about yy axis.

RATIO Permissible ratio of stresses as provided by the user.

The default value is 1.


Section 5C

5-50

Symbols Description

z ,rel ,z Slenderness ratios corresponding to bending about zz

axis. y,rel ,y Slenderness ratios corresponding to bending about yy

axis.

E0,05 Fifth percentile value of modulus of elasticity parallel

to grain. G0,05 Fifth percentile value of shear modulus parallel to

grain. Iz Second moment of area about the strong z-axis. Iy Second moment of area about the weak y-axis. Itor Torsional moment of inertia.

fmk Characteristic bending strength.

b, h Width and depth of beam.

Equations for Characteristic Values of Timber Species as per

Annex-A of EN 338:2003

The following equations were used to determine the characteristic

values:

Basic Inputs: For a particular Timber Strength Class (TSC), the

following characteristic strength values are

required to compute the other related characteristic

values.

1. Bending Strength – fm,k

2. Mean Modulus of Elasticity in bending – E0, mean

3. Density - k

Section 5C

5-51

Sl.

No. Property Symbol

Wood Type

Softwood

(C) Hardwood (D)

1. Tensile Strength

parallel to grain ft ,0,k 0.6 * fm,k

2. Tensile Strength

perpendicular to grain ft ,90,k Minimum of {0.6 and (0.0015*k)}

3. Compressive Strength

parallel to grain fc,0,k 5 * (fm,k )

0.45

4. Compressive Strength

perpendicular to grain fc,90,k 0.007*k 0.0015*k

5. Shear Strength fv,k Minimum of {3.8 and (0.2*fm,k 0.8)}

6. Modulus of Elasticity

parallel to grain E0,05 0.67* E0,mean 0.84* E0,mean

7.

Mean Modulus of

Elasticity

perpendicular to grain

E90,mean E0,mean /30 E0,mean /15

8. Mean Shear Modulus Gmean E0,mean /16

9. Shear Modulus G0,05 E0,05 /16

The values of the characteristic strengths computed using the

above equations, may differ with the tabulated values in Table-1 of

EN 338:2003. However, in all such cases, the values obtained from

the provided equations are treated as actual and is used by the

program, as the values of Table-1 are based on these equations.

Finding the Design values of Characteristic Strength

As per clause 2.4.1, Design values of a strength property shall be

calculated as:

mkd XmodKX


Section 5C

5-52

Where Xd is design value of strength property, Xk characteristic

value of strength property and m is partial factor for material

properties.

The member resistance in timber structure is calculated in STAAD

according to the procedures outlined in EC5. This depends on

several factors such as cross sectional properties, different load

and material factors, timber strength class, load duration class,

service class and so on. The methodology adopted in STAAD for

calculating the member resistance is explained here.

Check for Tension stresses

If the direction of applied axial tension is parallel to the direction

of timber grain alignment, the following formula should be

checked:

RATIO F S t0dt0d …….(cf : Equation 6.1 of EC-5-2004)

If the direction of applied axial tension is perpendicular to the

direction of timber grain alignment, the following formula should

be checked:

RATIO F S t90dt90d

Check for Compression stresses

If the direction of applied axial compression is parallel to the

direction of timber grain alignment, the following formula should

be checked:

RATIO F S c0dc0d …….(cf: Equation 6.2 of EC-5-

2004)

If the direction of applied axial compression is perpendicular to

the direction of timber grain alignment, the following formula

should be checked:

Section 5C

5-53

RATIO Kc90F S c90dc90d (cf: Equation 6.3 of EC-5-

2004)

Check for Bending stresses

If members are under bending stresses, the following conditions

should be satisfied. Please note that in STAAD z-z axis is the

strong axis:

RATIOF

SKm

F

S

myd

myd

mzd

mzd

.(cf: Equation 6.11 of EC-5-2004)

RATIOF

S

F

SKm

myd

myd

mzd

mzd

.(cf: Equation 6.12 of EC-5-2004)

Check for Shear stresses

Horizontal stresses are calculated and checked against allowable

values:

RATIOF

S

vd

vd

…….( cf: Equation 6.13 of EC-5-2004)

Check for Torsional stresses

Members subjected to torsional stress should satisfy the following

equation:

RATIOFKshape

S

tor_d

tor_d

.( cf: Equation 6.14 of EC-5-2004)


Section 5C

5-54

Check for combined Bending and Axial tension

Members subjected to combined action of bending and axial

tension stress should satisfy the following conditions. Please note

that in STAAD z-z axis is the strong axis:

RATIO F

SKm

F

S

F

S

myd

myd

mzd

mzd

t0d

t0d

…. (cf: Equation 6.17 of EC-5-2004)

RATIO F

S

F

SKm

F

S

myd

myd

mzd

mzd

t0d

t0d

…. ( cf: Equation 6.18 of EC-5-2004)

Check for combined Bending and axial Compression

If members are subjected to bending and axial compression stress,

following equations should be satisfied. Please note that in

STAAD z-z axis is the strong axis:

RATIO F

SKm

F

S

F

S

myd

myd

mzd

mzd

2

c0d

c0d

…. ( cf: Equation 6.19 of EC-5-2004)

RATIO F

S

F

SKm

F

S

myd

myd

mzd

mzd

2

c0d

c0d

…. ( cf: Equation 6.20 of EC-5-2004)

Section 5C

5-55

Stability check

(A) Column Stability check

The relative slenderness ratios should be calculated as

follows. Please note that in STAAD z-z axis is the strong

axis:

0,05

c0kzz,rel

E

S

…….( Equation 6.21 of EC-5-2004)

0,05

c0ky

y,relE

S

…….( Equation 6.22 of EC-5-2004)

If both rel ,z and rel ,y are less than or equal to 0.3 the

following conditions should be satisfied:

RATIO F

SKm

F

S

F

S

myd

myd

mzd

mzd

2

c0d

c0d

RATIO F

S

F

SKm

F

S

myd

myd

mzd

mzd

2

c0d

c0d

In other cases, the following conditions should be satisfied.

Please note that in STAAD z-z axis is the strong axis:

RATIO F

SKm

F

S

FKcz

S

myd

myd

mzd

mzd

c0d

c0d

… ( cf: Equation 6.23 of EC-5-2004)


Section 5C

5-56

RATIO F

S

F

SKm

FKcy

S

myd

myd

mzd

mzd

c0d

c0d

... ( cf: Equation 6.24 of EC-5-2004)

Where the symbols Kcz and Kcy are defined as follows.

Please note that in STAAD z-z axis is the strong axis:

2z,rel

2KzKz

1Kcz

...( Equation 6.25 of EC-5-2004)

2y,rel

2KzKy

1Kcy

…( Equation 6.26 of EC-5-2004)

2

z,relz,relc 3.015.0Kz ( Equation 6.27 of EC-5-2004)

2

y,rely,relc 3.015.0Ky .( Equation 6.28 of EC-5-2004)

The value of c incorporated in the software is the one for

solid timber ,i.e. 0.2.

(B) Beam Stability check

If members are subjected to only a moment about the strong

axis z, the stresses should satisfy the following equation:

RATIOFKcrit

S

mzd

mzd

.( cf: Equation 6.33 of EC-5-2004)

Section 5C

5-57

Where a combination of moment about the strong z -axis and

compressive force exists, the stresses should satisfy the

following equation:

RATIOFKcz

S

FKcrit

S

c0d

c0d

2

mzd

mzd

…… ( cf: Equation 6.35 of EC-5-2004)

Where,

mrel,2

mrel,

mrel,m,rel

mrel,

4.1for1

1.475.0for75.056.1

0.75 for 1

Kcrit

….. ( Equation 6.34 of EC-5-2004)

crit,m

mkm,rel

S

f ……..( Equation 6.30 of EC-5-2004)

For hardwood:

…. (Equation 6.31 of EC-5-2004)

For softwood:

05,0

ef

2

crit,m Elh

b78.0S

….( Equation 6.32 of EC-5-2004)

zef

tor05,0y05,0

crit,mWl

IGIES


Section 5C

5-58

5C.3 Design Parameters



altered to suite the particular structure.

Depending on the model being designed, the user may have to

change some or all of the parameter default values. Some

parameters are unit dependent and when altered, the new setting

must be compatible with the active “unit” specification.




Parameter

Name

Default

Value

Description

SCL 3 Service Class (Ref. Cl.2.3.1.3)

1 = Class 1, Moisture content <= 12%

2 = Class 2, Moisture content <= 20%

3 = Class 3, Moisture content > 20%

LDC 1 Load Duration Class (Ref. Cl.2.3.1.2),

required to get the K-MOD value from

Table – 3.1.

1 - Permanent action

2 - Long term action

3 - Medium term action

4 - Short term action

5 - Instantaneous action

Section 5C

5-59

Parameter

Name

Default

Value

Description

TSC 6 (C24) Timber Strength Class (Ref. Reference

EN338 – 2003)

Softwood: 1 = C14, 2 = C16, 3 = C18,

4 = C20, 5 = C22, 6 = C24, 7 = C27, 8 =

C30, 9 = C35, 10 = C40, 11 = C45, 12 =

C50.

Hardwood: 13 = D30, 14 = D35, 15 =

D40, 16 = D50, 17 = D60, 18 = D70.

This TSC definition will calculate the

corresponding characteristic strength

values using the equations as given in

BS-EN-338, Annex - A.

ALPHA 0.0 Angle of inclination of load to the grain

alignment. (Ref. Cl.6.1.1, Cl.6.1.2,

Cl.6.1.3, Cl.6.1.4)

0.0 = Load parallel to grain,

90.0 = Load Perpendicular to grain

KC90 1.0 Factor taking into account the load

configuration, possibility of splitting and

degree of compressive deformation. (Ref.

Cl.6.1.5-(2))

Range: 1.0 KC90 4.0

Other than the default value, user may

specify any value within the range,

depending on load-position, load-

dispersion, contact length at support

locations etc.


Section 5C

5-60

Parameter

Name

Default

Value

Description

MTYP 0 Member Type: Beam/Column. (Ref.

Cl.6.3.2, Cl.6.3.3)

0 – Not defined by the user – checks

both clauses (Default).

1 – Beam Member

2 – Column Member

This information is required to find which

stability check will be performed as per

the Cl 6.3 according to the Member Type.

KLEF 1.0

(Member

Length)

Effective Length Factor to check Lateral

Torsional Buckling. (Ref. Table 6.1)

Span of the beam depending on the

support conditions and load

configurations. The user will put the

appropriate value from the Table 6.1.

Required only for MTYP has a value of 1

(Beam).

KLY 1.0

(Member

Length)

Effective Length Factor for Local-y-axis.

(Ref. Cl.6.3.2), for the computation of the

relative slenderness ratios.

KLZ 1.0

(Member

Length)

Effective Length Factor for Local-z-axis.

(Ref. Cl.6.3.2), for the computation of the

relative slenderness ratios.

TRACK 0 Degree/Level of Details of design output

results.

Available options: 0 / 1 / 2

RATIO 1.0 Permissible ratio of actual to allowable

value.

Section 5C

5-61

Parameter

Name

Default

Value

Description

SERV No Default

Value

Defines the load case numbers – those are

to be considered for serviceability

(deflection) check.

The list of this parameter must contain

only the valid load-case numbers.

Deflection checks will be performed

only on those load-case results.

If this parameter is not provided ,

then in-spite of the presence of the

parameter DFF – the deflection check

will NOT be performed.

DFF No Default

Value

“Deflection Length” / Max. Allowable

Net Final Local Deflection.

In this case, deflection check will be

performed, if both the parameters SERV

and DFF are present with specific values.

For appropriate range of values, please

refer Cl.7.2 (Table 7.2)

DJ1 Start node number for a physical member

under consideration for Deflection Check.

DJ2 End node number for a physical member

under consideration for Deflection Check.

5C.4 Verification Problems


reference purposes.


Section 5C

5-62


A Timber Column of length 1.0 meter, having c/s dimension of 73

mm X 198 mm, is subjected to an axial compressive force of 50.0

kN.

Design of the member - ULTIMATE LIMIT STATE

Material properties:

Timber class: C24

Service classes: Class 2, moisture content <= 20%

Load duration classes: Medium-term

Cross section properties:

Length of the member is 1 m.

Rectangular cross section, b = 73 mm, h = 198 mm,

Effective cross sectional area A = 14454 mm²,

Radius of gyration of cross section about y-axis ry = 21 mm,

Radius of gyration of cross section about z-axis rz = 57 mm,

Section modulus of cross section about z-axis: Wz = 4.770x105 mm³

Section modulus of cross section about y-axis: Wy = 1.759x105 mm³

Characteristic material properties for timber:

Modification factor Kmod = 0.80 …from table 3.1

Material factors m = 1.30 … from table 2.3

fc0k = 21.00 N/mm²,

Fc0d = (Kmod.fc0k)/m = (0.80x21.00)/1.30 = 12.92 N/mm²[Cl

2.4.1(1)P]

Section 5C

5-63

Cross section loads:

Fx = 50.000 kN

Compression parallel to the grain:

Sc0d = (1000xFx)/A = (1000x50.000)/14454

= 3.46N/mm² < 12.92N/mm² (Fc0d)

The ratio of actual compressive stress to allowable

compressive strength:

= 3.46 / 12.92 = 0.268 < 1.0 [Cl. 6.1.4.(1)P]

Check for Slenderness:

Slenderness ratios: z = (1000/57) = 17.54 and y = (1000/21)

= 47.62

E0,mean = 1.1031 kN/m2

As timber grade is C24, i.e., Soft Wood, E0,05 = 0.67 * E0,mean

… [Annex A,EN 338:2003]

05,0

k0cy

y,relE

f

= 0.809

05,0

k0czz,rel

E

f

= 0.298

Since, rel ,y is greater than 0.3, following conditions should be

satisfied:

RATIO F

SKm

F

S

FK

S

mzd

mzd

myd

myd

c0dyc,

c0d

[Cl.

6.3.2.(3)]


Section 5C

5-64

RATIO F

SKm

F

S

FKcz

S

myd

myd

mzd

mzd

c0d

c0d

[Cl.

6.3.2.(3)]

2

yrel,yrel,y 3.1.5K = 0.878

2

zrel,zrel,z 3.1.5K = 0.541

2

y,rel

2

yy

y,c

KK

1K

= 0.82

2

z,rel

2

zz

z,c

KK

1K

= 1.0

For Rectangular cross section Km = 0.70. The member is

subjected to Compression only, so actual bending stress is

zero.

F

SKm

F

S

FK

S

mzd

mzd

myd

myd

c0dyc,

c0d= 0.326 + 0.0 + 0.0

= 0.326

F

SKm

F

S

FKcz

S

myd

myd

mzd

mzd

c0d

c0d= 0.268 + 0.0 + 0.0

= 0.268

Hence the critical ratio is 0.326 < 1.0 and the section is safe.

Section 5C

5-65

The Input File:

STAAD SPACE START JOB INFORMATION ENGINEER DATE END JOB INFORMATION INPUT WIDTH 79 UNIT METER KN JOINT COORDINATES 1 0 0 0; 2 1.0 0 0; MEMBER INCIDENCES 1 1 2; DEFINE MATERIAL START ISOTROPIC WOOD E 1.10316e+007 POISSON 0.15 DENSITY 0.00231749 ALPHA 5.5e-006 END DEFINE MATERIAL CONSTANTS MATERIAL WOOD MEMB 1 MEMBER PROPERTY 1 PRIS YD 0.198 ZD 0.073 SUPPORTS 1 FIXED LOAD 1 LOADTYPE NONE TITLE LOAD CASE 1 JOINT LOAD 2 FX -50 PERFORM ANALYSIS PARAMETER CODE TIMBER EC5 ALPHA 0 ALL LDC 3 ALL SCL 2 ALL TSC 6 ALL TRACK 2 ALL CHECK CODE ALL FINISH


Section 5C

5-66

The member checking part of the output file:

Section 5C

5-67


A Timber Column of length 1.0 meter, having c/s dimension of 73

mm X 198 mm, is subjected to an axial compressive force of 5.0

kN and moments of 2.0 kN.m and 1.0 kN.m about its major and

minor axes respectively.

Design of the member - ULTIMATE LIMIT STATE

Material properties:

Timber Strength Class: C24

Service classes: Class 2, moisture content <=20%

Load duration: Medium-term

Cross section properties:

Length of the member is 1 m.

Rectangular cross section, b = 73 mm, h = 198 mm,

Effective cross sectional area A = 14454 mm²,

Radius of gyration of cross section about y-axis ry = 21 mm,

Radius of gyration of cross section about z-axis rz = 57 mm,

Section modulus of cross section about z-axis: Wz = 4.770x105 mm³

Section modulus of cross section about y-axis: Wy = 1.759x105 mm³

Characteristic material properties for timber:

Modification factor, Kmod = 0.80

Material factor m = 1.30

fc0k = 21.00 N/mm², E0,05 = 7370 N/mm2,

Fc0d = Kmod.fc0k/m = (0.80x21.00)/1.30 = 12.92N/mm²

fmyk = 24.00 N/mm²,

Fmyd = Kmod.fmyk/m = (0.80x24.00)/1.30 = 14.77N/mm²

fmzk = 24.00 N/mm²,

Fmzd = Kmod.fmzk/m = (0.80x24.00)/1.30 = 14.77N/mm²


Section 5C

5-68

Cross section loads:

Fx = 5.000 kN, Mz = 2.000 kN.m, My = 1.000 kN.m

Check for Slenderness:

Slenderness ratios: z = (1000/57) = 17.54 and y = (1000/21)

= 47.62

05,0

k0cy

y,relE

f

= 0.809

05,0

k0czz,rel

E

f

= 0.298

Since, rel ,y is greater than 0.3, following conditions should be

satisfied:

RATIO F

SKm

F

S

FK

S

mzd

mzd

myd

myd

c0dyc,

c0d

[Cl. 6.3.2.(3)]

RATIO F

SKm

F

S

FKcz

S

myd

myd

mzd

mzd

c0d

c0d

[Cl. 6.3.2.(3)]

2

yrel,yrel,y 3.1.5K = 0.878

2

zrel,zrel,z 3.1.5K = 0.541

2

y,rel

2

yy

y,c

KK

1K

= 0.82

2

z,rel

2

zz

z,c

KK

1K

= 1.0

Section 5C

5-69

For Rectangular cross section Km = 0.70

Sc0d = (1000Fx/A) = (1000x5.000)/14454 = 0.35 N/mm²

Smzd = (106xMz)/Wz = (106x2.000)/(4.770x105) = 4.19 N/mm²

Smyd = (106xMy)/Wy = (106x1.000)/(1.759x105) = 5.69 N/mm²

F

SKm

F

S

FK

S

mzd

mzd

myd

myd

c0dyc,

c0d

= 0.033 + 0.385 + 0.198 = 0.616

F

SKm

F

S

FKcz

S

myd

myd

mzd

mzd

c0d

c0d

= 0.027 + 0.283 + 0.269 = 0.579

Hence the critical ratio is 0.616 < 1.0 and the section is safe.


Section 5C

5-70

The Input File:

STAAD SPACE START JOB INFORMATION ENGINEER DATE 08-Jun-05 END JOB INFORMATION INPUT WIDTH 79 UNIT METER KN JOINT COORDINATES 1 0 0 0; 2 0 1 0; MEMBER INCIDENCES 1 1 2; DEFINE MATERIAL START ISOTROPIC WOOD E 1.10316e+007 POISSON 0.15 DENSITY 0.00231749 ALPHA 5.5e-006 END DEFINE MATERIAL CONSTANTS MATERIAL WOOD MEMB 1 MEMBER PROPERTY 1 PRIS YD 0.198 ZD 0.073 SUPPORTS 1 FIXED LOAD 1 LOADTYPE NONE TITLE LOAD CASE 1 JOINT LOAD 2 FY -5.0 MX 1.0 MZ 2.0 PERFORM ANALYSIS PARAMETER CODE TIMBER EC5 ALPHA 0 ALL LDC 3 ALL SCL 2 ALL TSC 6 ALL TRACK 2 ALL CHECK CODE ALL FINISH

Section 5C

5-71

The member checking part of the output file:


Section 5C

5-72

Section 6

Egyptian Codes

A‟lkjdfl‟akjsfd

6-1

Concrete Design Per EGYPTIAN CODE - ECCS205


STAAD has the capability of performing design of concrete

beams, columns and slabs according to ECCS 203. The 2004

revision of the code is currently implemented. Given the width

and depth of a section, STAAD will calculate the required

reinforcement to resist the forces and moments.





input:

UNIT MM

MEMBER PROPERTY

1 3 TO 7 9 PRISM YD 450. ZD 250.

11 13 PR YD 350.

Section 6A

Concrete Design Per Egyptian Code ECC S205

Section 6A

6-2






design being performed. The following Beam Design Brief

contains a complete list of the available parameters and their

default values.




Section 6A

6-3



slenderness effects in the analysis and design of concrete

members. The first method is equivalent to the procedure

presented in ECCS203-2004 equation 4-11. In this section, the

code recognizes that additional moments induced by deflection are

present and states that these 'secondary' moments are accounted for

by the design formula in equation 6-38, 6-37 etc. This is the

method used in the design for concrete in STAAD.

Alternatively STAAD houses a PDELTA ANALYSIS facility,

which allows the effects of these second order moments to be

considered in the analysis rather than the design. In a PDELTA

analysis, after solving the joint displacements of the structure, the

additional moments induced in the structure are calculated. These

can be compared to those calculated using the formulation of

ECCS203-2004.

6A.5 Beam Design


forces, all active beam loadings are pre scanned to identify the






Section 6A

6-4

Design for Flexure





resist both of these critical sagging and hogging moments.

Currently, design of singly reinforced sections only is permitted. If

the section dimensions are inadequate as a singly reinforced

section, such a message will be permitted in the output. Flexural

design of beams is performed in two passes. In the first pass,

effective depths of the sections are determined with the






depths of sections calculated on the basis of reinforcement

provided after the preliminary design. Final provision s of flexural


guideline for the curtailment of reinforcements as per ECCS203-

2004. Although exact curtailment lengths are not mentioned

explicitly in the design output (finally which will be more or less

guided by the detailer taking into account of other practi cal

consideration), user has the choice of printing reinforcements

provided by STAAD at 13 equally spaced sections from which the

final detailed drawing can be prepared.

Design for Shear


torsional moments. Shear design is performed at 13 equally spaced

sections (0.to 1.) for the maximum shear forces amongst the active

load cases and the associated torsional moments. Shear capacity

calculation at different sections without the shear reinfor cement is

based on the actual tensile reinforcement provided by STAAD

program. Two-legged stirrups are provided to take care of the

balance shear forces acting on these sections.

Section 6A

6-5

Beam Design Output


Section 6A

6-6

6A.6 Column Design




critical load and is displayed. The requirements of ECCS203-2004

equation 6-37,6-38,6-41 etc are followed, with the user having

control on the effective length parameters. Bracing conditions are



requires additional moment calculations.

Section 6A

6-7

Column Design output


Section 6A

6-8

Shear Design Output

6-9

Steel Design Per EGYPTIAN CODE #205



implementation of Egyptian code of practice for structural steel

construction and bridges Code No. 205(Min Dec #279/2001)

design in STAAD. The design philosophy and procedural logistics

for member selection and code checking are based upon the

principles of allowable stress design. Two major failure modes are

recognized: failure by overstressing, and failure by stability

considerations. The flowing sections describe the salient features

of the allowable stresses being calculated and the stability criteria

being used. Members are proportioned to resist the design loads

without exceeding the allowable stresses and the most economic

section is selected on the basis of least weight criteria. The code

checking part of the program checks stability and strength

requirements and reports the critical loading condition and the

governing code criteria. It is generally assumed that the user will

take care of the detailing requirements like provision of stiffeners

and check the local effects such as flange buckling and web

crippling.

6B.2 Allowable Stresses

The member design and code checking in STAAD are based upon

the allowable stress design method as per Egyptian Code No. 205,

It is a method for proportioning structural members using design

loads and forces, allowable stresses, and design limitations for the

appropriate material under service conditions. It would not be

possible to describe every aspect of Egyptian Code: 205 in this

Section 6B

Steel Design Per Egyptian Code # 205

Section 6B

6-10

manual. This section, however, will discuss the salient features of

the allowable stresses specified by Egyptian Code: 205 and

implemented in STAAD. Appropriate sections of Egyptian Code:

205 will be referenced during the discussion of various types of

allowable stresses.

6B.2.1 Axial Stress

Tensile Stress

The allowable tensile stress, as calculated in STAAD as per

Egyptian Code: 205 is described below.

The estimated stress on the net effective sectional area in various

members, multiplied by the appropriate factor of safety shall not

exceed minimum guaranteed yield stress of the material.

The permissible stress in axial tension, at in MPa on the net

effective area of the sections shall not exceed: Clause: 2.6.2

Ft = 0.58 fy

where,

fy = minimum yield stress of steel in Mpa

Compressive Stress

Allowable compressive stress on the gross section of axially

loaded compression members shall not exceed the permissible

stress calculated based on the following formula: (Clause: 2.6.4)

Fc = 2

410

)75.058.0(58.0

y

y

FF

For all grade of steel:

For = kl/r 100

Fc = 7500/2

where,

Section 6B

6-11

Fc = Permissible stress in axial compression, in Mpa

fy = Yield stress of steel, in Mpa

=l/r = Slenderness ratio of the member, ratio of the effective

length to appropriate radius of gyration

6B.2.2 Bending Stress

The allowable bending stress in a member subjected to bending is

calculated based on the following formula: (Clause: 2.6.5)

The laterally unsupported length (Lu) of the compression flange is

limited by

y

f

uf

bL

20

Fbt or Fbc = 0.64 fy

Clause 2.6.5.5 Tension Fbt

Fbt = 0.58 Fy

Clause 2.6.5.5 Compression Fbc

I. Compression flange is braced laterally at intervals exceeding L u,

the allowable bending stress in compression Fbc will be taken as

follows.

i. for shallow thick flanged sections, where approximately

,4db

Lt

f

ufthe lateral tensional buckling stress is governed

by the torsion strength given by:

yb FC 58.0/AL

800 F

fudltb1

ii. For Deep flanged sections, where approximately

,4.0db

Lt

f

ufthe lateral torsional buckling stress governed

by the buckling strength given by:


Section 6B

6-12

a. When y

bTu

F

CrL 84/ then

Fl tb2 = 0.58 Fy

b. When y

bTu

y

b

F

CrL

F

C188/84 then

Fl tb2 =

yyb

yTuFF

C

FrL58.0

105176.1

2/64.0

c. When y

bTu

F

CrL 188/ then

Fl tb2

yb

Tu

FCrL

58.0/

12002

where,

Lu = Effective laterally unsupported length of compression flange.

k = Effective length factor

rT = radius of gyration about minor axis of a section compressing

the compression web area (in cms)

bf = Compression flange width

d = Total depth

Cb = Coefficient depending on the type of load and support

conditions as given in table 2.2

II. Compression on extreme fibers of channels bent about their major

axis

Fl tb = ybfu

FCAdL

58.0/.

800

where,

Fbt = Bending stress in tension

Fbc = Bending stress in compression

fy = Yield stress of steel, in MPa

Section 6B

6-13

6B.2.3 Shear Stress

Allowable shear stress calculations are based on Section 2.6.3 of

Egyptian code 205. For shear on the web, the gross section taken into

consideration consists of the product of the total depth and the web

thickness.

yall Fq 35.0

where,

allq = Allowable shear stress

6B.2.4 Combined Stress

Members subjected to both axial and bending stresses are

proportioned accordingly to following

Axial Compression and Bending

All the members subjected to bending and axial compression are

required to satisfy the equation of section 2.6.7.1

0.121 AF

fA

F

f

F

f

bcy

bcy

bcx

bcx

c

ca

where,

Ex

ca

mx

f

f

CA

1

1 ,

Ey

ca

my

f

f

CA

1

2

caf = Actual compression stress

Fc = Allowable compressive stress, clause 2.6.4.

bcxf bcyf = Actual Bending stress about x and y-axes respectively.

Fbcx,Fbcy = Allowable compressive bending stress, clause 2.6.5.

FEx,FEy = Euler stress in t/cm2

Cm = Moment modification factor


Section 6B

6-14

Axial Tension and Bending

All the members subject to bending and axial tension are required to satisfy

the equation of section 2.6.7.2

0.1bty

bty

btx

btx

t

ta

F

f

F

f

F

f

6B.3 Stability Requirements

Slenderness ratios are calculated for all members and checked

against the appropriate maximum values. Table 5.1 of Egyptian

code #205: summarizes the maximum slenderness ratios for

different types of members. In STAAD implementation of

Egyptian code #205, appropriate maximum slenderness ratio can

be provided for each member. If no maximum slenderness ratio is

provided, compression members will be checked against a

maximum value of 180 and tension members will be checked

against a maximum value of 300

6B.4 Code Checking

The purpose of code checking is to verify whether the specified

section is capable of satisfying applicable design code

requirements. The code checking is based on the Egyptian code

#205 requirements. Forces and moments at specified sections of

the members are utilized for the code checking calculations.

Sections may be specified using the BEAM parameter or the

SECTION command. If no sections are specified, the code

checking is based on forces and moments at the member ends.

The code checking output labels the members as PASSed or


location (distance from the start) and magnitudes of the governing

forces and moments are also printed out.

Section 6B

6-15




select the most economical section, that is , the lightest section,

which satisfies the applicable code requirements. The section

selected will be of the same type (I-Section, Channel etc.) as

originally specified by the user. Member selection may be

performed with all types of steel sections and user provided tables.

Selection of members, whose properties are originally provided

from user specified table, will be limited to sections in the user

provided table. Member selection can not be performed on

members whose cross sectional properties are specified as

PRISMATIC.

The process of MEMBER SELECTION may be controlled using

the parameters listed in Table 13B.1. It may be noted that the

parameters DMAX and DMIN may be used to specify member

depth constraints for selection. If PROFILE parameter is provided,

the search for the lightest section is restricted to that profile. Up to

three (3) profiles may be provided for any member with a section

being selected from each one.



result in a tabulated fashion as well as step by step procedure.


Section 6B

6-16

Section 6B

6-17

Table 6B.1 Egyptian Steel Design – Code #205 Parameters

Parameter

Name


FYLD 250 MPA

(36.25 KSI) Yield strength of steel.


SSY 0.0 0.0 = Sidesway in local y-axis. 1.0 = No sidesway

SSZ 0.0 Same as above except in local z-axis.

CMY

CMZ

0.85 for sidesway and

calculated for no sidesway

Cm value in local y & z axes

MAIN 180 (Comp. Memb.)

Allowable Kl/r for slenderness calculations for compression members.

TMAIN 300 (Tension Memb)

Allowable Kl/r for slenderness calculations for tension members.

DMAX 100.0 cm. Maximum allowable depth.

DMIN 0.0 cm. Minimum allowable depth.

RATIO 1.0 Permissible ratio of the actual to allowable stresses.

BEAM 3.0

0.0 = design only for end moments and those at locations specified by the SECTION command.

1.0 = calculate section forces at twelfth points along the beam, design at each intermediate location and report the critical location where ratio is maximum.

PROFILE - Search for the lightest section for the profile mentioned.

DFF None





all codes.


Section 6B

6-18

Section 7

French Codes

A‟lkjdfl‟akjsfd

7-1

Concrete Design Per B.A.E.L.


STAAD has the capabilities for performing design of concrete

beams, columns and slabs according to B.A.E.L. - 1983. Given the

width and depth (or diameter for circular columns) of a section,

STAAD will calculate the required reinforcing to resist the various

input loads.



perform design per B.A.E.L. These parameters not only act as a

method to input required data for code calculations but give the

engineer control over the actual design process. Default values, of

commonly used numbers in conventional design practice, have

been used for simplicity. Table 5A.1 contains a complete list of

available parameters and their default values.


STAAD provides the user two methods of accounting for the

slenderness effect in the analysis and design of concrete members.

The first method is a procedure which takes into account second

order effects. Here, STAAD accounts for the secondary moments,

due to axial loads and deflections, when the PDELTA ANALYSI S

command is used. STAAD, after solving for the joint

displacements of the structure, calculates the additional moments

induced in the structure. Therefore, by using PDELTA

Section 7A


Section 7A

7-2

ANALYSIS, member forces are calculated which will require no

user modification before beginning member design.

The second method by which STAAD allows the user to account

for the slenderness effect is through user supplied moment

magnification factors. Here the user approximates the additional

moment by supplying a factor by which moments will be

multiplied before beginning member design.





UNIT MM

MEMBER PROPERTIES

1 3 to 7 9 PRISM YD 450 ZD 300.

11 13 PR YD 300.


mm depth and 300 mm width) and the second set of members, with


with a 300 mm diameter. Note that area (AX) is not provided for

these members. If shear areas (AY & AZ) are to be considered in

analysis, the user may provide them along with YD and ZD. Also

note that moments of inertia may be provided, but if not provided,

the program will calculate values from YD and ZD.

Section 7A

7-3

7A.5 Beam Design

Beam design includes both flexure and shear. For both types of


moment and shear envelopes, and locate critical sections. The total

number of sections considered is twelve, unless that number is

redefined with the NSECTION parameter. From the critical


developed, with cut-off lengths calculated to include required

development length.

Shear design includes critical shear values plus torsional moments.

From these values, stirrup sizes are calculated with proper spacing.

The stirrups are assumed to be U-shaped for beams with no

torsion, and closed hoops for beams subject to torsion.

Table 7A.1 French Concrete Design Parameters


Name Value

FYMAIN * 300 N/mm2 Yield Stress for main reinforcing steel.

FYSEC * 300 N/mm2 Yield Stress for secondary reinforcing steel.

FC * 30 N/mm2 Concrete Yield Stress.

CLEAR * 20 mm Clearance of reinforcing bar. Value is automatically set to 20 mm for C35 and higher.

MINMAIN 8 mm Minimum main reinforcement bar size. (8mm - 60mm).

MINSEC 8 mm Minimum secondary reinforcement bar size. (8mm - 60mm).

MAXMAIN 50 mm Maximum main reinforcement bar size. (8mm - 60mm).

SFACE *0.0 Face of support location at start of beam. (Only considers shear - use MEMBER OFFSET for bending).


Section 7A

7-4

Table 7A.1 French Concrete Design Parameters


Name Value

EFACE *0.0 Face of Support Location at end of beam. (Note: Both SFACE and EFACE are input as positive numbers.).

TRACK 0.0 Critical Moment will not be printed out with beam design report. A value of 1.0 will mean a print out.

MMAG 1.0 A factor by which the design moments will be magnified.


WIDTH ZD Width of the concrete member. This value defaults to ZD as provided under MEMBER PROPERTIES.

DEPTH YD Depth of concrete member. This value defaults to YD as provided under MEMBER PROPERTIES.

Note: Once a parameter is specified, its value stays at that specified number till it is specified again. This is the way STAAD works for all codes. * These values must be provided in the units the user is currently using for input.


UNIT NEWTON MMS


CODE FRENCH

FYMAIN 415 ALL

FYSEC 415 ALL

FC 35 ALL

CLEAR 25 MEM 2 TO 6


SFACE 100 MEMB 7 TO 9

EFACE 100 MEMB 7 TO 9


Section 7A

7-5


DESIGN BEAM 2 TO 9

END CONCRETE DESIGN

7A.6 Column Design

Columns are designed for axial force and biaxial moments at the


loading which produces maximum reinforcement i s called the


circular sections. For rectangular and square sections, the

reinforcement is always assumed to be equally distributed on each

side. That means the total number of bars will always be a multiple

of four (4). This may cause slightly conservative results in some

cases.


UNIT NEWTON MMS


CODE FRENCH

FYMAIN 415 ALL

FC 35 ALL


MMAG 1.5 MEMB 4 5



END CONCRETE DESIGN


Slab and walls are designed per BAEL 1983 specifications. To

design a slab or wall, it must be modeled using finite elements.


Section 7A

7-6

The command specifications are in accordance with Chapter II,

section 6.40.


moments are obtained from the element force output (see Chapter

2 of the Technical Reference Manual). The reinforcement required

to resist Mx moment is denoted as longitudinal reinforcement and

the reinforcement required to resist My moment is denoted as

transverse reinforcement. The parameters FYMAIN, FC, and

CLEAR listed in Table 5A.1 are relevant to slab design. Other

parameters mentioned in Table 5A.1 are not applicable to s lab

design.

LONG.

TRANS.

X

Y

Z

M

MM

Mx

y

x

y


UNIT NEWTON MMS


CODE FRENCH

FYMAIN 415 ALL

FC 25 ALL

CLEAR 40 ALL


END CONCRETE DESIGN

7-7

Steel Design Per the French Code


STAAD implementation of French Steel Design is based on Centre

Technique Industriel de la Construction Metallique publication

entitled "Design Rules for Structural Steelwork."



proportioned according to the limit states of which they would

become unfit for their intended use. Two major categories of limit -

states are recognized: ultimate and serviceability. The primary

considerations in ultimate limit state design are strength and

stability; that in serviceability is deflection. Appropriate load and

resistance factors are used so that uniform reliability is achieved

for all steel structures under various loading conditions and at the

same time the chances of limits being surpassed are acceptably

remote.




section is selected on the basis of the least weight criteria, as


depths, desired section type, or other related parameters. The code

checking portion of the program verifies that code requirements

for each selected section are met and also identifies the governing

criteria.

Section 7B

Steel Design per the French Code

Section 7B

7-8

The following sections describe the salient features of STAAD

implementation of "Design Rules for Structural Steelwork." A

detailed description of the design process, along with its

underlying concepts and assumptions, is available in the

specification document.

7B.2 Basis of Methodology

The "Design Rules for Structural Steelwork (Revision 80)" permits

the usage of elastic analysis. Thus, in STAAD, linear elastic

analysis method is used to obtain the forces and moments in the

members. However, strength and stability considerations are based

on the principles of plastic behaviour. Axial compression buckling

and lateral torsional buckling are taken into consideration for

calculation of axial compression resistance and flexural resistance

of members. Slenderness calculations are made and overall

geometric stability is checked for all members.


The member strengths are calculated in STAAD according to the

procedures outlined in section 4 of this specification. Note that the

program automatically considers co-existence of axial force, shear

and bending in calculating section capacities.

For axial tension capacity, procedures of section 4.2 are followed.

For axial compression capacity, formulas of section 5.3 are used.

Moment capacities about both axes are calculated using the

procedures of sections 4.5 and 4.6. Lateral torsional buckling is

considered in calculating ultimate twisting moment per section

5.22 of the specification. The parameter UNL (see Table 6B.1)

must be used to specify the unsupported length of the compression

flange for a laterally unsupported member. Note that this length i s

also referred to as twisting length.

Section 7B

7-9

7B.4 Combined Axial Force and Bending

The procedures of sections 4.55 and 5.32 are implemented for

interaction of axial forces and bending. Appropriate interaction

equations are used and the governing criterion is determined.




design decisions from the engineer to the program, thus allowing


specific needs.

The default parameter values have been selected as frequently used

numbers for conventional design. Depending on the particular

design requirements, some or all of these parameter values may be

changed to exactly model the physical structure.

7B.6 Code Checking and Member Selection

Both code checking and member selection options are available in

STAAD implementation of CM 66 (Revn. 80). For general

information on these options, refer to Chapter II, sections 3.4 and

3.5. For information on specification of these commands, refer to

Chapter II, and section 6.46.


Results of code checking and member selection are presented in

the output file in a tabular format.

Please note the following: COND CRITIQUE refers to the section

of the CM 66 (Revn. 80) specification which governed the design.


Section 7B

7-10

If the TRACK parameter is set to 1.0, calculated member

capacities will be printed. The following is a detailed description

of printed items:

PC = Member Compression Capacity

TR = Member Tension Capacity

MUZ = Member Moment Capacity (about z-axis)

MUY = Member Moment Capacity (about y-axis)

VPZ = Member Shear Capacity (z-axis)

VPY = Member Shear Capacity (y-axis)

Table 7B.1 French Steel Design Parameters


Name Value

KY 1.0 K value for axial compression buckling about local Y-axis. Usually, this is the minor axis.

KZ 1.0 K value for axial compression buckling about local Z-axis. Usually, this is the major axis.

LY Member Length Length to calculate slenderness ratio about Y-axis for axial compression.

LZ Member Length Length to calculate slenderness ratio about Z-axis for axial compression.



UNL Member Length Unsupported length of compression flange for calculating moment resistance.

UNF 1.0 Same as above provided as a fraction of member length.

TRACK 0.0 0.0 = Suppress printing of all design strengths. 1.0 = Print all design strengths.

DMAX 100.0 cm. Maximum allowable depth (used in member selection).

DMIN 0.0 cm. Minimum allowable depth (used in member selection).

RATIO 1.0 Permissible ratio of actual load effect and design strength.

Section 7B

7-11

Table 7B.1 French Steel Design Parameters


Name Value

BEAM 0.0 0.0 = design only for end moments and those at locations specified by SECTION command. 1.0 = calculate moments at tenth points along the beam, and use maximum Mz for design.




STAAD contains a broad set of facilities for designing structural

members as individual components of an analyzed structure. The

member design facilities provide the user with the ability to carry

out a number of different design operations. These facilities may

be used selectively in accordance with the requirements of the

design problem. The operations to perform a design are:

Specify the members and the load cases to be considered in the

design.

Specify whether to perform code checking or member

selection.


values.



Currently STAAD supports steel design of wide flange, S, M, HP

shapes, angle, double angle, channel, double channel, beams with

cover plate, composite beams and code checking of prismatic

properties.


Section 7B

7-12


UNIT METER

PARAMETER

CODE FRENCH

NSF 0.85 ALL

UNL 10.0 MEMBER 7

KY 1.2 MEMBER 3 4

RATIO 0.9 ALL

TRACK 1.0 ALL

CHECK CODE ALL

7B.8 Built-in French Steel Section Library

The following information is provided for use when the built-in





for these members.

An example of the member property specification in an input file is

provided at the end of this section.



user interface.


Section 7B

7-13

IPE Shapes

These shapes are designated in the following way.

10 15 TA ST IPE140

20 TO 30 TA ST IPEA120

33 36 TO 46 BY 2 TA ST IPER180

HE shapes

HE shapes are specified as follows.

3 5 TA ST HEA120A

7 10 TA ST HEM140

13 14 TA ST HEB100

IPN Shapes

The designation for the IPN shapes is similar to that for the IPE

shapes.

25 TO 35 TA ST IPN200

23 56 TA ST IPN380

T Shapes


by referring to the I beam shapes from which they are cut. For

example,

1 5 TA T IPE140

2 8 TA T HEM120


Section 7B

7-14

U Channels

Shown below is the syntax for assigning 4 different names of channel

sections.

1 TO 5 TA ST UAP100

6 TO 10 TA ST UPN220

11 TO 15 TA ST UPN240A

16 TO 20 TA ST UAP250A

Double U Channels




11 TA D UAP150

17 TA D UAP250A SP 0.5


channel UAP150 with no spacing in between. Member 17 is a

double channel UAP250A with a spacing of 0.5 length units

between the channels.

Angles



16 20 TA ST L30X30X2.7


a leg thickness of 2.7mm. This specification may be used when the

local Z axis corresponds to the z-z axis specified in Chapter 2. If

the local Y axis corresponds to the z-z axis, type specification

"RA" (reverse angle) should be used instead of ST.

17 21 TA RA L25X25X4

Section 7B

7-15

22 24 TA RA L100X100X6.5

Note that if the leg thickness is a round number such as 4.0, only

the number 4 appears in the section name, the decimal part is not

part of the section name.

Double Angles





33 35 TA SD L30X20X4 SP 0.6

37 39 TA LD L80X40X6

43 TO 47 TA LD L80X80X6.5 SP 0.75


Section names of tubes, just like angles, consist of the depth,

width and wall thickness as shown below.

64 78 TA ST TUB50252.7

66 73 TA ST TUB2001008.0

Members 64 and 78 are tubes with a depth of 50mm, width of 25mm

and a wall thickness of 2.7mm. Members 66 and 73 are tubes with a

depth of 200mm, width of 100mm and a wall thickness of 8.0mm.

Unlike angles, the ".0" in the thickness is part of the section name.

Tubes can also be input by their dimensions instead of by their table

designations. For example,



Section 7B

7-16

is a tube that has a depth of 8 length units, width of 6 length units,

and a wall thickness of 0.5 length units. Only code checking, no

member selection, will be performed for TUBE sections specified i n

this way.


To designate circular hollow sections, use PIP followed by numerical

value of the diameter and thickness of the section in mm omitting the

decimal portion of the value provided for the diameter. The following

example illustrates the designation.

8 TO 28 TA ST PIP422.6

3 64 78 TA ST PIP21912.5

Members 8 to 28 are pipes 42.4mm in dia, having a wall thickness

of 2.6mm. Members 3, 64 and 78 are pipes 219.1mm in dia, having

a wall thickness of 12.5mm.




specifies a pipe with outside dia. of 25 length units and inside dia.

of 20 length units. Only code checking, no member selection will

be performed if this type of specification is used.

SAMPLE FILE CONTAINING FRENCH SHAPES

STAAD SPACE

UNIT METER KN

JOINT COORD

1 0 0 0 15 140 0 0

MEMB INCI

1 1 2 14

Section 7B

7-17

UNIT CM

MEMBER PROPERTIES FRENCH

* IPE SHAPES

1 TA ST IPEA120

* IPN SHAPES

2 TA ST IPN380

*HE SHAPES

3 TA ST HEA200

* T SHAPES

4 TA T HEM120

* U CHANNELS

5 TA ST UAP100

* DOUBLE U CHANNELS

6 TA D UAP150 SP 0.5

* ANGLES

7 TA ST L30X30X2.7

* REVERSE ANGLES

8 TA RA L25X25X4

* DOUBLE ANGLES - SHORT LEGS BACK

* TO BACK

9 TA SD L30X20X4 SP 0.25

* DOUBLE ANGLES - LONG LEGS BACK

* TO BACK

10 TA LD L80X40X6 SP 0.75

* TUBES (RECTANGULAR OR SQUARE

* HOLLOW SECTIONS)

11 TA ST TUB50252.7

* TUBES (RECTANGULAR OR SQUARE

* HOLLOW SECTIONS)



13 TA ST PIP422.6



PRINT MEMB PROP

FINI


Section 7B

7-18

Section 8

German Codes

Aslkdfj;alskjdf‟

8-1

Concrete Design Per DIN 1045


STAAD has the capabilities of performing concrete design based

on the DIN 1045 - November 1989. Slab design is also avai lable

but this follows the requirements of Baumann, Munich, which is

the basis for Eurocode 2. Design for a member involves

calculation of the amount of reinforcement required for the

member. Calculations are based on the user specified properties

and the member forces obtained from the analysis. In addition, the

details regarding placement of the reinforcement on the cross

section are also reported in the output.



designed.

For Beams - Prismatic (Rectangular & Square)

For Columns - Prismatic (Rectangular, Square and Circular)





input:

Section 8A


Section 8A 8-2

UNIT MM

MEMBER PROPERTY

1 3 TO 7 9 PRISM YD 450. ZD 250.

11 13 PR YD 350.




with 350mm diameter. It is absolutely imperative that the user not




compression members. There are two options by which the

slenderness effect can be accommodated.

The first method is equivalent to the procedure presented in DIN

1045 17.4.3/17.4.4 which is used as the basis for commonly used

design charts considering e/d and sk/d for conditions where the

slenderness moment exceeds 70. This method has been adopted in

the column design in STAAD per the DIN code.

The second option is to compute the secondary moments through

an analysis. Secondary moments are caused by the interaction of

the axial loads and the relative end displacements of a member.

The axial loads and joint displacements are first determined from

an elastic stiffness analysis and the secondary moments are then

evaluated. To perform this type of analysis, use the command

PDELTA ANALYSIS instead of PERFORM ANALYSIS in the

input file. The user must note that to take advantage of this

analysis, all the combinations of loading must be provided as




Section 8A

8-3




automatically. The column is designed for the total moment which

is the sum of the primary and secondary forces. The secondar y

moments can be compared to those calculated using the charts of

DIN 1045.

8A.5 Beam Design


forces, all active beam loadings are prescanned to identify the


number of sections considered is 13 (e.g. 0., .1, .2, .25, .3, .4, .5,

.6, .7, .75, .8, .9 and 1). All of these sections are scanned to

determine the design force envelopes.

Design for Flexure


beam) and hogging (creating tensile stress at the top face) moments

are calculated for all active load cases at each of the above mentioned

sections. Each of these sections is designed to resist these critical

sagging and hogging moments. Currently, design of singly reinforced

sections only is permitted. If the section dimensions are inadequate as

a singly reinforced section, such a message will be printed in the

output. Flexural design of beams is performed in two passes. In the

first pass, effective depths of the sections are determined with the




single or multiple layers. The entire flexural design is performed


depths of sections calculated on the basis of reinforcement provided

after the preliminary design. Final provisions of flexural


guideline for the curtailment of reinforcements as per the DIN code.

Although exact curtailment lengths are not mentioned explicitly in the

design output (finally which will be more or less guided by the


Section 8A 8-4

detailer taking into account of other practical considerations), the user

has the choice of printing reinforcements provided by STAAD at 13

equally spaced sections from which the final detailed drawing can be

prepared.

Design for Shear and Torsion

Shear design in STAAD conforms to the specifications of section

17.5 of DIN 1045. Shear reinforcement is calculated to resist both

shear forces and torsional moments. Shear and torsional design is

performed at the start and end sections of the member at a distance

"d" away from the node of the member where "d" is the effective

depth calculated from flexural design. The maximum shear forces

from amongst the active load cases and the associated torsional

moments are used in the design. The capacity of the concrete in

shear and torsion is determined at the location of design and the

balance, if any, is carried by reinforcement. It is assumed that no

bent-up bars are available from the flexural reinforcement to carry

and "balance" shear. Two-legged stirrups are provided to take care

of the balance shear forces acting on these sections. Stirrups are

assumed to be U-shaped for beams with no torsion, and closed

hoops for beams subject to torsion.


UNIT NEWTON MMS


CODE GERMAN

FYMAIN 415 ALL

FYSEC 415 ALL

FC 35 ALL

CLEAR 25 MEM 2 TO 6



DESIGN BEAM 2 TO 9

END CONCRETE DESIGN

Section 8A

8-5

8A.6 Column Design



The loading which yields maximum reinforcement is called the

critical load. The requirements of DIN 1045-figure 13, for

calculating the equilibrium equations for rectangular and circular

sections from first principles, is implemented in the design. The

user has control of the effective length (sk) in each direction by

using the ELZ and ELY parameters as described on Table 8A.1.

This means that the slenderness will be evaluated along with e/d to

meet the requirements of DIN 1045 section 17.4.3 and 17.4.4.

Column design is done for square, rectangular and circular

sections. Square and rectangular columns are designed with

reinforcement distributed on all four sides equally. That means the

total number of bars will always be a multiple of four (4). This

may cause slightly conservative results in some cases. The

TRACK parameter may be used to obtain the design details in

various levels of descriptivity.


UNIT NEWTON MMS


CODE GERMAN

FYMAIN 415 ALL

FC 35 ALL




END CONCRETE DESIGN


Section 8A 8-6

8A.7 Slab Design

To design a slab, it must first be modeled using finite elements and

analysed. The command specifications are in accordance with

Chapter 2 and Chapter 6 of the Technical Reference Manual. Slabs

are designed to specifications as described by BAUMANN of

MUNICH which is the basis for Eurocode 2.




to resist the Mx moment is denoted as longitudinal reinforcement

and the reinforcement required to resist the My moment is denoted

as transverse reinforcement. The following parameters are those

applicable to slab design:

1. FYMAIN Yield stress for all reinforcing steel

2. FC Concrete grade

3. CLEAR Distance from the outer surface of the elemen t to

the edge of the bar. This is considered the same on

both top and bottom surfaces of the element.

4. SRA Parameter which denotes the angle of direction of

the required transverse reinforcement relative to

the direction of the longitudinal reinforcement for

the calculation of BAUMANN design forces.

The other parameters shown in Table 7A.1 are not applicable to

slab design.

BAUMANN equations

If the default value of zero is used, the design will be based on Mx

and My forces which are obtained from the STAAD analysis. The

SRA parameter (Set Reinforcement Angle) can be manipulated to

introduce resolved BAUMANN forces into the design replacing

the pure Mx and My moments. These new design moments allow

the Mxy moment to be considered when designing the section,

resolved as an axial force. Orthogonal or skew reinforcement may

Section 8A

8-7

be considered. If SRA is set to -500, an orthogonal layout will be

assumed. If however a skew is to be considered, an angle is given

in degrees measured from the local element X axis anticlockwise

(positive). The resulting Mx* and My* moments are calculated and

shown in the design format.

The design of the slab considers a fixed bar size of 10mm in the

longitudinal direction and 8mm in the transverse. The longitudinal

bar is the layer closest to the slab exterior face.






design being performed. Table 8A.1 of this manual contains a

complete list of the available parameters and their default values.

It is necessary to declare length and force units as Millimeter and

Newton before performing the concrete design. Note: Once a

parameter is specified, its value stays at that specified number

till it is specified again. This is the way STAAD works for all

codes.

Table 8A.1 German Concrete Design Parameters

Parameter

Name


FYMAIN 420 N/mm2 Yield Stress for main reinforcement (For slabs it is 500 N/mm2 for both directions)

FYSEC 420N/mm2 Yield Stress for secondary reinforcement. Applicable to shear and torsion reinforcement in beams

FC 25N/mm2 Concrete Yield Stress/ cube strength

MINMAIN 16mm Minimum main reinforcement bar size [Acceptable bar sizes: 6 8 10 12 14 16 20 25 32 40 50]

MINSEC 8mm Minimum secondary reinforcement bar


Section 8A 8-8


Parameter

Name


size. Applicable to shear and torsion reinforcement in beams.

CLEAR 25mm Clear cover for reinforcement measured from concrete surface to closest bar perimeter.

MAXMAIN 50 mm Maximum required reinforcement bar size. Acceptable bars are per MINMAIN above.

SFACE 0.0 Face of support location at start of beam, measured from the start joint. (Only applicable for shear - use MEMBER OFFSET for bending)

EFACE 0.0 Face of support location at end of beam, measured from the end joint. (NOTE: Both SFACE & EFACE must be positive numbers.)

TRACK 0.0 0.0 = Critical Moment will not be printed with beam design report.


2.0 = For beams gives area of steel required at intermediate sections. (see NSECT)

MMAG 1.0 Factor by which design moments are magnified for column design

NSECTION 10 Number of equally-spaced sections to be considered in finding critical moment for beam design. The upper limit is 20

WIDTH ZD Width of concrete member. The default value is as provided as ZD in MEMBER PROPERTIES.

DEPTH YD Depth of concrete member. The default value is as provided as YD in MEMBER PROPERTIES.

ELY 1.0 Member length factor about local Y direction

Section 8A

8-9


Parameter

Name


for column design

ELZ 1.0 Member length factor about local Z direction for column design


-500 = Orthogonal reinforcement layout considering Mxy

A = Skew angle considered in BAUMANN equations. A is the angle in degrees.


Section 8A 8-10

8-11

Steel Design Per the DIN Code

8B.1 General


implementation of the DIN code of practice for structural steel

design (DIN 18800 and DIN 4114) in STAAD. The design

philosophy and procedural logistics are based on the principles of

elastic analysis and allowable stress design. Facilities are available

for member selection as well as code checking. Two major failure

modes are recognized: failure by overstressing and failure by

stability considerations. The following sections describe the

salient features of the design approach.


exceedance of the allowable stresses or capacities and the most

economical section is selected on the basis of the least weight

criteria. The code checking part of the program also checks the

slenderness requirements and the stability criteria. Users are

recommended to adopt the following steps in performing the steel

design:

1) Specify the geometry and loads and perform the analysis.

2) Specify the design parameter values if different from the

default values.

3) Specify whether to perform code checking or member

selection.

Section 8B

Steel Design per the DIN Code

Section 8B 8-12





complete flexibility in providing loading specifications and in

using appropriate load factors to create necessary loading

situations. Depending upon the analysis requirements, regular

stiffness analysis or P-Delta analysis may be specified. Dynamic

analysis may also be performed and the results combined with

static analysis results.


For specification of member properties of standard German steel

sections, the steel section library available in STAAD may be

used. The next section describes the syntax of commands used to

assign properties from the built-in steel table. Member properties

may also be specified using the User Table facility. For more

information on these facilities, refer to the STAAD Program User's

manual.

8B.4 Built-in German Steel Section Library



These properties are stored in a database file. If called for, these



for these members during the analysis. An example of member


section.

Section 8B

8-13


section library may be obtained using the tools of the graphical

user interface.


IPE Shapes

These shapes are designated in the following way:

20 TO 30 TA ST IPEA120

33 36 TO 46 BY 2 TA ST IPER140

HE Shapes

The designation for HE shapes is similar to that for IPE shapes.

25 TO 35 TA ST HEB300

23 56 TA ST HEA160

I Shapes

I shapes are identified by the depth of the section. The following

example illustrates the designation.

14 15 TA ST I200 (indicates an I-section with 200mm depth)

T Shapes


by referring to the I beam shapes from which they are cut. For

example,

1 5 TA T HEA220

2 8 TA T IPE120


Section 8B 8-14

U Channels

The example below provides the command for identifying two

channel sections. The former (U70X40) has a depth of 70mm and a

flange width of 40mm. The latter (U260) has a depth of 260mm.

11 TA D U70X40

27 TA D U260

Double Channels


them, are available. The letter “D” in front of the section name

will specify a double channel, e.g. D U180. The spacing between

the double channels is provided following the expression “SP”.

11 TA D U180

27 TA D U280 SP 0.5 (Indicates 2 channels back to back

spaced at 0.5 length units)

Angles



16 20 TA ST L20X20X2.5


a leg thickness of 2.5mm. The above specification may be used

when the local z-axis corresponds to the Z-Z axis specified in

Chapter 2. If the local y-axis corresponds to the Z-Z axis, type

specification "RA" (reverse angle) may be used.

17 21 TA RA L40X20X5

Section 8B

8-15

Double Angles


be specified by using the word SD or LD, respectively, in front of

the angle size. In case of an equal angle, either SD or LD will

serve the purpose. Spacing between the angles is provided by

using the word SP and the spacing value following the section

name.

14 TO 20 TA SD L40X20X4 SP 0.5

21 TO 27 TA LD L40X20X4 SP 0.5


To designate circular hollow sections, use PIP followed by

numerical value of the diameter and thickness of the section in mm

omitting the decimal section of the value provided for diameter.

The following example will illustrate the designation.

8 TO 28 TA ST PIP602.9 (60.3mm dia, 2.9mm wall

thickness)

3 64 67 TA ST PIP40612.5 (406.4mm dia, 12.5mm wall

thickness)




specifies a pipe with outside dia. of 25 and inside dia. of 20 in

current length units. Only code checking and no member selection

will be performed if this type of specification is used.


Section 8B 8-16


Tube names are input by their dimensions. For example,

15 TO 25 TA ST TUB100603.6

is the specification for a tube having sides of 100mmX60mm and

the wall thickness of 3.6mm.

Tubes, like pipes can also be input by their dimensions (Height,

Width and Thickness) instead of by their table designations.


is a tube that has a height of 8, a width of 6, and a wall thickness

of 0.5 in current length units. Only code checking and no member

selection will be performed for TUBE sections specified this way.

SAMPLE INPUT FILE CONTAINING GERMAN SHAPES

STAAD SPACE

UNIT METER KN

JOINT COORDINATES

1 0 0 0 15 140 0 0

MEMBER INCIDENCES

1 1 2 14

UNIT CM

MEMBER PROPERTIES GERMAN

* IPE SHAPES

1 TA ST IPEA120

* HE SHAPES

2 TA ST HEB300

* I SHAPES

3 TA ST I200

* T SHAPES

4 TA T HEA220

Section 8B

8-17

* U CHANNELS

5 TA ST U70X40

* DOUBLE U CHANNELS

6 TA D U260

* ANGLES

7 TA ST L20X20X2.5

* REVERSE ANGLES

8 TA RA L40X20X5

* DOUBLE ANGLES - LONG LEGS BACK TO BACK

9 TA LD L40X20X4 SP 0.5

* DOUBLE ANGLES - SHORT LEGS BACK TO BACK

10 TA SD L40X20X4 SP 0.5

* PIPES

11 TA ST PIP602.9

* PIPES


* TUBES

13 TA ST TUB100603.6

* TUBES

14 TA ST TUBE DT 8.0 WT 6.0 WT 0.5

*


FINISH


The allowable stresses used in the implementation are based on

DIN 18800 (Part 1) - Section 7. The procedures of DIN 4114 are

used for stability analysis. The basic measure of member

capacities are the allowable stresses on the member under various

conditions of applied loading such as allowable tensile stress,

allowable compressive stress etc. These depend on several factors

such as cross sectional properties, slenderness factors, unsupported

width to thickness ratios and so on. Explained here is the

procedure adopted in STAAD for calculating such capacities.


Section 8B 8-18




member is calculated on the basis of the member area. STAAD

calculates the tension capacity of a given member based on a user

supplied net section factor (NSF-a default value of 1.0 is present

but may be altered by changing the input value, see Table 6B.1)

and proceeds with member selection or code checking.



according to the procedure of DIN 4114 (Part 1) - Section 7.

Compressive resistance is a function of the slenderness of the

cross-section (Kl/r ratio) and the user may control the slenderness

value by modifying parameters such as KY, LY, KZ and LZ.

Allowable stress for Bending and Shear

The permissible bending compressive and tensile stresses are

dependent on such factors as length of outstanding legs, thickness

of flanges, unsupported length of the compression flange (UNL,

defaults to member length) etc. Shear capacities are a function of

web depth, web thickness etc. Users may use a value of 1.0 or 2.0

for the TRACK parameter to obtain a listing of the bending and

shear capacities.




locations of the member for all modeled loading situations.

Members subjected to axial force and bending are checked using

the criteria of DIN 18800 (Part 1) - Section 6.1.6. In addition, for

members with compression and bending, the criteria of DIN 4114

(Part 1) - Section 10 is used. Similarly, for members with axial

tension and bending, the criteria of DIN 4114 (Part 1) - Section 15

is used.

Section 8B

8-19





engineer to the program. The default parameter values have been

selected such that they are frequently used numbers for

conventional design. Depending on the particular design

requirements of the situation, some or all of these parameter

values may have to be changed to exactly model the physical

structure. Note: Once a parameter is specified, its value stays at

that specified number till it is specified again. This is the way


Table 8B.1 German Steel Design Parameters

Parameter

Name


KY 1.0 K value in local y-axis. Usually, this is the minor axis.

KZ 1.0 K value in local z-axis. Usually, this is the major axis.

LY Member Length Length in local y-axis to calculate slenderness ratio.

LZ Member Length Length in local z-axis to calculate slenderness ratio.

PY 240 N/sq.mm Strength of steel.


UNL Member Length Unrestrained member length in lateral torsional buckling checks.

UNF 1.0 Same as above provided as a factor of actual member length.

BEAM 0.0 Number of sections to be checked per member: 0.0 = Design only for end sections. 1.0 = Check at location of maximum MZ

along member.


Section 8B 8-20


Parameter

Name


2.0 = Check ends plus location of beam 1.0 check.

3.0 = Check at every 1/13th of the member length and report the maximum.

TRACK 0.0 Level of detail in output file: 0.0 = Output summary of results 1.0 = Output summary of results plus

member capacities

2.0 = Output detailed results


SGR 0.0 Grade of steel:

0.0 = St 37-2

1.0 = St 52-3

2.0 = StE 355

SBLT 0 Specify section as either rolled or built-up:

0 = Rolled

1 = Built-up

Cb 0 Beam coefficient n, defined in Table 9: If Cb = 0, program will use n = 2.5 for rolled sections and 2.0 for welded sections.

Cmm 1.0 Moment factor, Zeta, defined in Table 10:

1.0 = fixed ended member with constant moment, Zeta = 1.0

2.0 = pin ended member with UDL, Zeta = 1.12

3.0 = pin ended member with central point load, Zeta = 1.35

4.0 = fixed ended member, Zeta calculated from end moments.

DMAX 1.0 m Maximum allowable depth during member selection

DMIN 0.0 m Minimum required depth during member

Section 8B

8-21


Parameter

Name


selection

SAME 0.0 Control of sections to try during a SELECT process:

0.0 = Try every section of the same type as the original.

1.0 = Try only those with a similar name.

8B.8 Code Checking


section properties of the members are adequate to carry the forces

transmitted to it by the loads on the structure. The adequacy is

checked per the DIN requirements.






zero (default), design will be based on member start and end

forces. The code checking output labels the members as PASSed or


location (distance from start joint) and magnitudes of the

governing forces and moments are also printed.


Section 8B 8-22









the user table. Member selection cannot be performed on TUBES,

PIPES or members listed as PRISMATIC.


UNIT METER

PARAMETER

CODE GERMAN

NSF 0.85 ALL

UNL 10.0 MEMBER 7

KY 1.2 MEMBER 3 4

RATIO 0.9 ALL

TRACK 1.0 ALL

CHECK CODE ALL

Section 9

Indian Codes

Ad;flaksd;lfka

9-1

Concrete Design Per IS456



on limit state method of IS: 456 (2000).



designed.

For Beams Prismatic (Rectangular & Square), T-Beams and

L-shapes






input:

Section 9A


Section 9A

9-2

UNIT MM

MEMBER PROPERTY

1 3 TO 7 9 PRISM YD 450. ZD 250.

11 13 PR YD 350.

14 TO 16 PRIS YD 400. ZD 750. YB 300. ZB 200.

will be done accordingly. In the above input, the first set of

members are rectangular (450 mm depth and 250mm width) and

the second set of members, with only depth and no width provided,

will be assumed to be circular with 350 mm diameter. The third set

numbers in the above example represen ts a T-shape with 750 mm

flange width, 200 width, 400 mm overall depth and 100 mm flange

depth (See section 6.20.2). The program will determine whether

the section is rectangular, flanged or circular and the beam or

column design



perform design as per IS:456(2000). Default parameter values



suit the particular design being performed. Table 8A.1 of this




design.



compression members. The IS:456 code specifies two options by

which the slenderness effect can be accommodated (Clause 39.7).

Section 9A

9-3

One option is to perform an exact analysis which will take into

account the influence of axial loads and variable moment of inertia

on member stiffness and fixed end moments, the effect of

deflections on moment and forces and the effect of the duration of

loads. Another option is to approximately magnify design

moments.

STAAD has been written to allow the use of the first options. To

perform this type of analysis, use the command PDELTA

ANALYSIS instead of PERFORM ANALYSIS. The PDELTA

ANALYSIS will accommodate all requirements of the second-

order analysis described by IS:456, except for the effects of the

duration of the loads. It is felt that this effect may be safely

ignored because experts believe that the effects of the duration of

loads are negligible in a normal structural configuration.

Although ignoring load duration effects is somewhat of an

approximation, it must be realized that the approximate evaluation

of slenderness effects is also an approximate method. In this

method, additional moments are calculated based on empirical

formula and assumptions on sidesway

(Clause 39.7.1 and 39.7.1.1,IS: 456 - 2000).

Considering all these information, a PDELTA ANALYSIS, as

performed by STAAD may be used for the design of concrete

members. However the user must note, to take advantage of this





the P-delta analysis based on the deflections. Also note that the


provided by user. STAAD does not factor the loads automatically.

9A.6 Beam Design


effect the axial force may be taken into consideration. For all


Section 9A

9-4






Design for Flexure





resist both of these critical sagging and hogging moments. Where

ever the rectangular section is inadequate as singly reinforced

section, doubly reinforced section is tried. However, presently the

flanged section is designed only as singly reinforced section under

sagging moment. It may also be noted all flanged sections are

automatically designed as rectangular section under hogging

moment as the flange of the beam is ineffective under hogging

moment. Flexural design of beams is performed in two passes. In

the first pass, effective depths of the sections are determined with

the assumption of single layer of assumed reinforcement and



single or multiple layers. The entire flexure design is per formed

again in a second pass taking into account of the changed effective

depths of sections calculated on the basis of reinforcement provide

after the preliminary design. Final provisions of flexural


guideline for the curtailment of reinforcements as per IS:456-2000

(Clause 26.2.3). Although exact curtailment lengths are not

mentioned explicitly in the design output (finally which will be

more or less guided by the detailer taking into account of other

practical consideration), user has the choice of printing

reinforcements provided by STAAD at 11 equally spaced sections

from which the final detail drawing can be prepared.

Section 9A

9-5

Design for Shear


torsional moments. Shear design are performed at 11 equally

spaced sections (0.to 1.) for the maximum shear forces amongst

the active load cases and the associated torsional moments. Shear

capacity calculation at different sections with out the shear

reinforcement is based on the actual tensile reinforcement

provided by STAAD program. Two-legged stirrups are provided to

take care of the balance shear forces acting on these sections.

As per Clause 40.5 of IS:456-2000 shear strength of sections (< 2d

where d is the effective depth) close to support has been enhanced,

subjected to a maximum value of cmax.

Beam Design Output


reinforcement provided at 5 equally spaced (0,.25,.5,.75 and 1.)

sections along the length of the beam. User has option to get a

more detail output. All beam design outputs are given in IS units.

An example of rectangular beam design output with the default

output option (TRACK 0.0) is presented below:


Section 9A

9-6

============================================================================ B E A M N O. 12 D E S I G N R E S U L T S M20 Fe415 (Main) Fe415 (Sec.) LENGTH: 4000.0 mm SIZE: 250.0 mm X 350.0 mm COVER: 30.0 mm DESIGN LOAD SUMMARY (KN MET) ---------------------------------------------------------------------------- SECTION |FLEXTURE (Maxm. Sagging/Hogging moments)| SHEAR (in mm) | P MZ MX Load Case | VY MX Load Case ---------------------------------------------------------------------------- 0.0 | 0.00 0.00 0.00 4 | 29.64 1.23 4

| 0.00 -25.68 1.23 4 | 400.0 | 0.00 0.00 0.00 4 | 27.97 1.23 4 | 0.00 -16.05 1.23 4 | 800.0 | 0.00 0.00 0.00 4 | 25.12 1.23 4 | 0.00 -7.17 1.23 4 | 1200.0 | 0.00 0.97 0.49 5 | 21.11 1.23 4

| 0.00 -0.14 1.32 6 | 1600.0 | 0.00 6.77 1.23 4 | 15.93 1.23 4 | 0.00 0.00 0.00 4 |

2000.0 | 0.00 11.06 1.23 4 | 9.59 1.23 4 | 0.00 0.00 0.00 4 | 2400.0 | 0.00 13.04 1.23 4 | 2.08 1.23 4

| 0.00 0.00 0.00 4 | 2800.0 | 0.00 12.45 1.23 4 | -5.43 1.23 4 | 0.00 0.00 0.00 4 | 3200.0 | 0.00 9.55 1.23 4 | -11.77 1.23 4 | 0.00 0.00 0.00 4 | 3600.0 | 0.00 4.73 1.23 4 | -16.95 1.23 4

| 0.00 0.00 0.00 4 | 4000.0 | 0.00 0.00 0.00 4 | -25.48 1.23 4 | 0.00 -17.36 1.23 4 | ----------------------------------------------------------------------------

SUMMARY OF REINF. AREA (Sq.mm) ---------------------------------------------------------------------------- SECTION 0.0 mm 1000.0 mm 2000.0 mm 3000.0 mm 4000.0 mm ----------------------------------------------------------------------------

TOP 259.04 161.29 0.00 0.00 176.31 REINF. (Sq. mm) (Sq. mm) (Sq. mm) (Sq. mm) (Sq. mm)

BOTTOM 0.00 160.78 160.78 160.78 0.00 REINF. (Sq. mm) (Sq. mm) (Sq. mm) (Sq. mm) (Sq. mm) ----------------------------------------------------------------------------


---------------------------------------------------------------------------- SECTION 0.0 mm 1000.0 mm 2000.0 mm 3000.0 mm 4000.0 mm ---------------------------------------------------------------------------- TOP 4-10Ø 3-10Ø 2-10Ø 2-10Ø 3-10Ø REINF. 1 layer(s) 1 layer(s) 1 layer(s) 1 layer(s) 1 layer(s)

BOTTOM 2-12Ø 2-12Ø 2-12Ø 2-12Ø 2-12Ø REINF. 1 layer(s) 1 layer(s) 1 layer(s) 1 layer(s) 1 layer(s)

SHEAR 2 legged 8Ø 2 legged 8Ø 2 legged 8Ø 2 legged 8Ø 2 legged 8Ø REINF. @ 100 mm c/c @ 100 mm c/c @ 100 mm c/c @ 100 mm c/c @ 100 mm c/c

----------------------------------------------------------------------------

============================================================================

Section 9A

9-7

9A.7 Column Design



The loading which yield maximum reinforcement is called the


circular sections. By default, square and rectangular columns and

designed with reinforcement distributed on each side equally for

the sections under biaxial moments and with reinforcement

distributed equally in two faces for sections under uniaxial

moment. User may change the default arrangement of the

reinforcement with the help of the parameter RFACE (see Table

8A.1). Depending upon the member lengths, section dimensions

and effective length coefficients specified by the user STAAD

automatically determine the criterion (short or long) of the column

design. All major criteria for selecting longitudinal and transverse

reinforcement as stipulated by IS:456 have been taken care of in

the column design of STAAD. Default clear spacing between main

reinforcing bars is taken to be 25 mm while arrangement of

longitudinal bars.








output is given in SI units. An example of a long column design

(Ref.Example9 of SP:16, Design Aids For Reinforced Concrete to

IS:456-1978) output (with option TRACK 1.0) is given below.


Section 9A

9-8

============================================================================ C O L U M N N O. 1 D E S I G N R E S U L T S M20 Fe415 (Main) Fe415 (Sec.)

LENGTH: 3000.0 mm CROSS SECTION: 250.0 mm dia. COVER: 40.0 mm ** GUIDING LOAD CASE: 5 BRACED LONG COLUMN

DESIGN FORCES (KNS-MET) ----------------------- DESIGN AXIAL FORCE (Pu) : 62.0

About Z About Y INITIAL MOMENTS : 2.21 32.29

MOMENTS DUE TO MINIMUM ECC. : 1.24 1.24 SLENDERNESS RATIOS : 12.00 12.00 MOMENTS DUE TO SLENDERNESS EFFECT : 1.12 1.12 MOMENT REDUCTION FACTORS : 1.00 1.00 ADDITION MOMENTS (Maz and May) : 1.12 1.12

TOTAL DESIGN MOMENTS : 3.32 33.40 REQD. STEEL AREA : 1822.71 Sq.mm. MAIN REINFORCEMENT : Provide 17 - 12 dia. (3.92%, 1922.65 Sq.mm.) (Equally distributed)

TIE REINFORCEMENT : Provide 8 mm dia. rectangular ties @ 190 mm c/c SECTION CAPACITY (KNS-MET) --------------------------

Puz : 992.70 Muz1 : 36.87 Muy1 : 36.87

INTERACTION RATIO: 1.00 (as per Cl. 38.6, IS456)

============================================================================

Section 9A

9-9

Table 9A.1 Indian Concrete Design IS456 Parameters


FYMAIN 415 N/mm2 Yield Stress for main reinforcing steel.



CLEAR 25 mm 40 mm

For beam members. For column members







COLUMN DESIGN






Section 9A

9-10









For TRACK = 0.0, output consists of reinforcement details at START, MIDDLE and END. For TRACK = 1.0, critical moments are printed in addition to TRACK 0.0 output. For TRACK = 2.0, required steel for intermediate sections defined by NSECTION are printed in addition to TRACK 1.0 output.

COLUMN DESIGN:

With TRACK = 0.0, reinforcement details are printed. With TRACK = 1.0, column interaction analysis results are printed in addition to TRACK 0.0 output. With TRACK = 2.0, a schematic interaction diagram and intermediate interaction values are printed in addition to TRACK 1.0 output.

With TRACK = 9.0, the details of section capacity calculations are printed.


Section 9A

9-11





ULY 1.0 Ratio of unsupported length to actual length of column about minor axis.

ULZ 1.0 Ratio of unsupported length to actual length of column about major axis.

TORSION 0.0 A value of 0.0 means torsion to be considered in beam design. A value of 1.0 means torsion to be neglected in beam design.

SPSMAIN 25 mm Minimum clear distance between main reinforcing bars in beam and column. For column centre to centre distance between main bars cannot exceed 300mm.

SFACE 0.0 Face of support location at start of beam. It is used to check against shear at the face of the support in beam design. The parameter can also be used to check against shear at any point from the start of the member.

EFACE 0.0 Face of support location at end of beam. The parameter can also be used to check against shear at any point from the end of the member. (Note: Both SFACE and EFACE are input as positive numbers).


Section 9A

9-12



ENSH 0.0 Perform shear check against enhanced shear strength as per Cl. 40.5 of IS456:2000. ENSH = 1.0 means ordinary shear check to be performed ( no enhancement of shear strength at sections close to support) For ENSH = a positive value(say x ), shear strength will be enhanced up to a distance x from the start of the member. This is used only when a span of a beam is subdivided into two or more parts. (Refer note ) For ENSH = a negative value(say –y), shear strength will be enhanced up to a distance y from the end of the member. This is used only when a span of a beam is subdivided into two or more parts.(Refer note) If default value (0.0) is used the program will calculate Length to Overall Depth ratio. If this ratio is greater than 2.5, shear strength will be enhanced at sections (<2d) close to support otherwise ordinary shear check will be performed.

RENSH 0.0 Distance of the start or end point of the member from its nearest support. This parameter is used only when a span of a beam is subdivided into two or more parts. (Refer note)

Bar combination has been introduced for detailing. Please refer section 8A.8 for details. Notes: Value of ENSH parameter (other than 0.0 and 1.0) is used only

when the span of a beam is subdivided into two or more parts. When this

condition is aroused RENSH parameter is also to be used.

Once a parameter is specified, its value stays at that specified


codes.

Section 9A

9-13

The span of the beam is subdivided four parts, each of length L

metre. The shear strength will be enhanced up to X metre from

both supports. The input should be the following:

Steps:

ENSH L MEMB 1 => Shear strength will be enhanced

throughout the length of the member 1,

positive sign indicates length

measured from start of the member

ENSH (X-L) MEMB 2 => Shear strength will be enhanced up to

a length (X-L) of the member 2, length

measured from the start of the member

ENSH –L MEMB 4 => Shear strength will be enhanced

throughout the length of the member 4,

negative sign indicates length

measured from end of the member

ENSH –(X-L) MEMB 3 => Shear strength will be enhanced up to

a length (X-L) of the member 3, length

measured from the end of the member

RENSH L MEMB 2 3 => Nearest support lies at a distance L

from both the members 2 and 3.

DESIGN BEAM 1 TO 4=> This will enhance the shear strength

up to length X from both ends of the

beam consisting of members 1 to 4 and

gives spacing accordingly.


Section 9A

9-14

At section = y1 from start of member 1 av = y1

At section = y2 from the start of member 2 av = y2+L

At section = y3 from the end of member 3 av = y3+L

At section = y4 from end of member 4 av = y4

where c, enhanced = 2dc/av

At section 0.0, av becomes zero. Thus enhanced shear strength will

become infinity. However for any section shear stress cannot

exceed c, max. Hence enhanced shear strength is limited to a

maximum value of c, max.

9A.8 Bar Combination

Initially the program selects only one bar to calculate the number

of bars required and area of steel provided at each section along

the length of the beam. Now, two bar diameters can be specified to

calculate a combination of each bar to be provided at each section.

The syntax for bar combination is given below.

START BAR COMBINATION

MD1 <bar diameter> MEMB <member list>

MD2 <bar diameter> MEMB <member list>

END BAR COMBINATION

Section 9A

9-15

MD2 bar diameter should be greater than MD1 bar diameter. The typical output for bar combination is shown below:

OUTPUT FOR BAR COMBINATION

--------------------------------------------------------------

| M A I N R E I N F O R C E M E N T |

--------------------------------------------------------------

SECTION | 0.0- 2166.7 | 2166.7- 6500.0 | 6500.0- 8666.7 |

| mm | mm | mm |

--------------------------------------------------------------

TOP | 6-20í + 1-25í| 2-20í + 1-25í | 2-20í |

| in 2 layer(s)| in 1 layer(s) | in 1 layer(s) |

Ast Reqd| 2330.22 | 1029.90 | 582.55 |

Prov| 2376.79 | 1119.64 | 628.57 |

Ld (mm) | 940.2 | 940.2 | 940.2 |

--------------------------------------------------------------

BOTTOM | 4-20í | 2-20í | 2-20í |

|in 1 layer(s) | in 1 layer(s) | in 1 layer(s) |

Ast Reqd| 1165.11 | 582.55 | 582.55 |

Prov| 1257.14 | 628.57 | 628.57 |

Ld (mm) | 940.2 | 940.2 | 940.2 |

-------------------------------------------------------------

The beam length is divided into three parts, two at its ends and one at span. Ld gives the development length to be provided at the two ends of each section.

9A.9 Wall Design in accordance with IS 456-2000

Design of walls in accordance with IS 456-2000 is available in

STAAD.Pro.

Design is performed for in-plane shear, in-plane and out-of-plane

bending and out-of-plane shear. The wall has to be modeled using

STAAD‟s Surface elements. The use of the Surface element

enables the designer to treat the entire wall as one entity. It greatly

simplifies the modeling of the wall and adds clarity to the analysis

and design output. The results are presented in the context of the

entire wall rather than individual finite elements thereby allowing

users to quickly locate required information.


Section 9A

9-16

The program reports shear wall design results for each load

case/combination for user specified number of sections given by

SURFACE DIVISION (default value is 10) command. The shear

wall is designed at these horizontal sections. The output includes

the required horizontal and vertical distributed reinforcing, the

concentrated (in-plane bending) edge reinforcing and the link

required for out-of-plane shear.

General format:


CODE INDIAN

FYMAIN f1

FC f2

HMIN f3

HMAX f4

VMIN f5

VMAX f6

EMIN f7

EMAX f8

LMIN f9 LMAX f10

CLEAR f11

TWOLAYERED f12

KSLENDER f13

DESIGN SHEARWALL LIST shearwall-list

END

Section 9A

9-17

The following table explains the parameters used in the shear wall

design. Note: Once a parameter is specified, its value stays at




Parameter Name Default

Value

Description

FYMAIN 415 Mpa Yield strength of steel, in current units.

FC 30 Mpa Compressive strength of concrete, in current units.

HMIN 8 Minimum size of horizontal reinforcing bars (range 6 mm – 36 mm). If input is 6 (integer number) the program will assume 6 mm diameter bar.

HMAX 36 Maximum size of horizontal reinforcing bars (range 6 mm – 36 mm). If input is 6 (integer number) the program will assume 6 mm diameter bar.

VMIN 8 Minimum size of vertical reinforcing bars (range 6mm – 36mm). If input is 6 (integer number) the program will assume 6 mm diameter bar.

VMAX 36 Maximum size of vertical reinforcing bars (range 6mm – 36mm). If input is 6 (integer number) the program will assume 6 mm diameter bar.

EMIN 8 Minimum size of vertical reinforcing bars located in edge zones (range 6mm – 36mm). If input is 6 (integer number) the program will assume 6 mm diameter bar.

EMAX 36 Maximum size of vertical reinforcing bars located in edge zones (range 6mm – 36mm). If input is 6 (integer number) the program will assume 6 mm diameter bar.

LMIN 6 Minimum size of links (range 6mm – 16mm). If input is 6 (integer number) the program will assume 6 mm diameter bar.


Section 9A

9-18


Parameter Name Default

Value

Description

LMAX 16 Maximum size of links (range 6mm – 16mm). If input is 6 (integer number) the program will assume 6 mm diameter bar.

CLEAR 25 mm Clear concrete cover, in current units. TWOLAYERED 0 Reinforcement placement mode:

0 - single layer, each direction 1 - two layers, each direction

KSLENDER 1.0 Slenderness factor for finding effective height. Table 6

The following example illustrates the input for the definition of

shear wall and design of the wall.

Example

.

.

SET DIVISION 12

SURFACE INCIDENCES

2 5 37 34 SUR 1

19 16 65 68 SUR 2

11 15 186 165 SUR 3

10 6 138 159 SUR 4

.

.

.

SURFACE PROPERTY

1 TO 4 THI 18

SUPPORTS

1 7 14 20 PINNED

2 TO 5 GEN PIN

6 TO 10 GEN PIN

Section 9A

9-19

11 TO 15 GEN PIN

19 TO 16 GEN PIN

.

.

.

SURFACE CONSTANTS

E 2.17185e+007

POISSON 0.17

DENSITY 23.5616

ALPHA 1e-005

.

.

START SHEARWALL DES

CODE INDIAN

UNIT NEW MMS

FC 25

FYMAIN 415

TWO 1

VMIN 12

HMIN 12

EMIN 12

DESIGN SHEA LIST 1 TO 4

END

Notes

1. Command SET DIVISION 12 indicates that the surface

boundary node-to-node segments will be subdivided into 12

fragments prior to finite element mesh generation.

2. Four surfaces are defined by the SURFACE INCIDENCES

command.

3. The SUPPORTS command includes the new support

generation routine. For instance, the line 2 TO 5 GEN PIN

assigns pinned supports to all nodes between nodes 2 and 5.

As the node-to-node distances were previously subdivided

by the SET DIVISION 12 command, there will be an


Section 9A

9-20

additional 11 nodes between nodes 2 and 5. As a result, all

13 nodes will be assigned pinned supports. Please note that

the additional 11 nodes are not individually accessible to the

user. They are created by the program to enable the finite

element mesh generation and to allow application of

boundary constraints.

4. Surface thickness and material constants are specified by the

SURFACE PROPERTY and SURFACE CONSTANTS,

respectively.

5. The shear wall design commands are listed between lines

START SHEARWALL DES and END. The CODE

command selects the design code that will be the basis for

the design. For Indian code the parameter is INDIAN. The

DESIGN SHEARWALL LIST command is followed by a

list of previously defined Surface elements intended as shear

walls and/or shear wall components.

Technical Overview

The program implements provisions of section 32 of IS 456-2000

and relevant provisions as referenced therein, for all active load

cases. The following steps are performed for each of the horizontal

sections of the wall.

Checking of slenderness limit

The slenderness checking is done as per clause no. 32.2.3. The

default effective height is the height of the wall. User can change

the effective height. The limit for slenderness is taken as 30.

Design for in-plane bending and vertical load (denoted by Mz

& Fy in the shear wall force output)

Walls when subjected to combined in-plane horizontal and vertical

forces produce in-plane bending in conjunction with vertical load.

According to clause no. 32.3.1, in-plane bending may be neglected

in case a horizontal cross section of the wall is always under

compression due combined effect of horizontal and vertical loads.

Otherwise, the section is checked for combined vertical load and

Section 9A

9-21

in-plane moment as column with axial load and uni-axial bending.

For this purpose, the depth is taken as 0.8 x horizontal length of

wall and breadth is the thickness of the wall. The reinforcement is

concentrated at both ends (edges) of the wall. The edge

reinforcement is assumed to be distributed over a len gth of 0.2

times horizontal length on each side. Minimum reinforcements are

according to clause no. 32.5.(a). Maximum 4% reinforcement is

allowed.

Design for in-plane shear (denoted by Fxy in the shear wall

force output)

By default, the program does not design only at the critical section

but at all the horizontal sections. By suitable use of the surface

division command, design at critical section as per clause no.

32.4.1 can be performed.

The design for in-plane shear is done as per clause no. 32.4. The

nominal shear stress is calculated as per clause no. 32.4.2 and it is

checked with the maximum allowable shear stress as per clause no.

32.4.2.1. The design shear strength of concrete is calculated as per

clause no. 32.4.3. Design of shear reinforcement is done as per

clause no. 32.4.4. Minimum reinforcements are as per clause no.

32.5.

Design for vertical load and out-of-plane vertical bending

(denoted by Fy and My respectively in the shear wall force

output)

Apart from the in-plane bending and horizontal shear force, the

wall is also subjected to out-of-plane bending in the vertical and

horizontal directions. The part of the wall which is not having

edge reinforcements (i.e. a zone of depth 0.6 x Length of the wall),

is designed again as column under axial load (i.e. vertical load)

and out-of-plane vertical bending. The minimum reinforcements

and maximum allowable spacings of reinforcements are as per

clause no. 32.5


Section 9A

9-22

Design for out-of-plane horizontal bending (denoted by Mx in

the shear wall force output)

The horizontal reinforcement which is already provided for in -

plane shear is checked against out-of-plane horizontal bending.

The wall is assumed as a slab for this purpose.

Design for out-of-plane shears (denoted by Qx and Qy in the

shear wall force output)

The out-of-plane shear arises from out-of-plane loading. The

nominal shear stresses are calculated as per clause no. 40.1.

Maximum allowable shear stresses are as per table 20. For shear

force in the vertical direction, shear strength of concrete section is

calculated as per section 4.1 of SP 16 : 1980 considering vertical

reinforcement as tension reinforcement. Similarly, for shear force

in the horizontal direction, shear strength of concrete section is

calculated considering horizontal reinforcement as tension

reinforcement. Shear reinforcements in the form of links are

computed as per the provisions of clause no. 40.4.

Shear Wall Design With Opening

The Surface element has been enhanced to allow design of shear

walls with rectangular openings. The automatic meshing algorithm

has been improved to allow variable divisions along wall and

opening(s) edges. Design and output are available for user selected

locations.

Description

Shear walls modeled in STAAD.Pro may include an unlimited

number of openings. Due to the presence of openings, the wall

may comprise up with different wall panels.

Section 9A

9-23

1. Shear wall set-up

Definition of a shear wall starts with a specification of the surface

element perimeter nodes, meshing divisions along node-to-node

segments, opening(s) corner coordinates, and meshing divisions of

four edges of the opening(s).

SURFACE INCIDENCE n1, ..., ni SURFACE s DIVISION sd1, ...,

sdj -

RECOPENING x1 y1 z1 x2 y2 z2 x3 y3 z3 x4 y4 z4 DIVISION

od1, ..., odk

where,

n1, ..., ni - node numbers on the perimeter of the shear wall,

s - surface ordinal number,

sd1, ..., sdj - number of divisions for each of the node-to-node distance on the surface perimeter,

x1 y1 z1 (...) - coordinates of the corners of the opening,

od1, ..., odk - divisions along edges of the opening.

Note:

If the sd1, ..., sdj or the od1, ..., odk list does not include all node-

to-node segments, or if any of the numbers listed equals zero, then

the corresponding division number is set to the default value (=10,

or as previously input by the SET DIVISION command).

Default locations for stress/force output, design, and design output

are set as follows:

SURFACE DIVISION X xd

SURFACE DIVISION Y yd


Section 9A

9-24

where,

xd - number of divisions along X axis,

yd - number of divisions along Y axis.

Note:

xd and yd represent default numbers of divisions for each edge of

the surface where output is requested. The output is provided for

sections located between division segments. For example, if the

number of divisions = 2, then the output will be produced for only

one section (at the center of the edge).

2. Stress/force output printing

Values of internal forces may be printed out for any user -defined

section of the wall. The general format of the command is as

follows:

PRINT SURFACE FORCE (ALONG ) (AT a) (BETWEEN d1, d2)

LIST s1, ...,si

where,

- local axis of the surface element (X or Y),

a - distance along the axis from start of the member

to the full cross-section of the wall,

d1, d2 - coordinates in the direction orthogonal to ,

delineating a fragment of the full cross-section for

which the output is desired. **

s1, ...,si - list of surfaces for output generation

** The range currently is taken in terms of local axis. If the local

axis is directed away from the surface, the negative range is to be

entered.

Section 9A

9-25

Note:

If command ALONG is omitted, direction Y (default) is assumed.

If command AT is omitted, output is provided for all sections

along the specified (or default) edge. Number of sections will be

determined from the SURFACE DIVISION X or SURFACE

DIVISION Y input values. If the BETWEEN command is

omitted, the output is generated based on full cross-section width.

3. Definition of wall panels

Input syntax for panel definition is as follows:

START PANEL DEFINITION

SURFACE i PANEL j ptype x1 y1 z1 x2 y2 z2 x3 y3 z3 x4 y4 z4

END PANEL DEFINITION

where,

i - ordinal surface number,

j - ordinal panel number,

ptype - panel type, one of: WALL, COLUMN, BEAM

x1 y1 z1 (...) - coordinates of the corners of the panel,

4. Shear wall design

The program implements different provisions of design of walls as

per code BS 8110. General syntax of the design command is as

follows:


(...)

DESIGN SHEARWALL (AT c) LIST s

END SHEARWALL DESIGN


Section 9A

9-26

Note:

If the command AT is omitted, the design proceeds for all cross

sections of the wall or panels, as applicable, defined by the

SURFACE DIVISION X or SURFACE DIVISION Y input

values.

a. No panel definition.

Design is performed for the specified horizontal full cross-section,

located at a distance c from the origin of the local coordinates

system. If opening is found then reinforcement is provided along

sides of openings. The area of horizontal and vertical bars

provided along edges of openings is equal to that of the respective

interrupted bars.

b. Panels have been defined.

Only wall panel design is supported in Indian code.

9-27


9A1.1 Design Operations

Earthquake motion often induces force large enough to cause

inelastic deformations in the structure. If the structure is brittle,

sudden failure could occur. But if the structure is made to behave

ductile, it will be able to sustain the earthquake effects better with

some deflection larger than the yield deflection by absorption of

energy. Therefore ductility is also required as an essential element

for safety from sudden collapse during severe shocks.

STAAD has the capabilities of performing concrete design as per

IS 13920. While designing it satisfies all provisions of IS 456 –

2000 and IS 13920 for beams and columns.

9A1.2 Section Types for Concrete Design


designed.

For Beams Prismatic (Rectangular & Square) & T-shape


Section 9A1


Section 9A1

9-28

9A1.3 Design Parameters

The program contains a number of parameters that are needed to

perform design as per IS 13920. It accepts all parameters that are

needed to perform design as per IS:456. Over and above it has

some other parameters that are required only when designed is

performed as per IS:13920. Default parameter values have been



suit the particular design being performed. Table 8A1.1 of this




design.

9A1.4 Beam Design


effect of the axial force may be taken into consideration. For all



number of sections considered is 13. All of these sections are

scanned to determine the design force envelopes.

For design to be performed as per IS:13920 the width of the

member shall not be less than 200mm(Clause 6.1.3). Also the

member shall preferably have a width-to depth ratio of more than

0.3 (Clause 6.1.2).

The factored axial stress on the member should not exceed 0.1fck

(Clause 6.1.1) for all active load cases. If it exceeds allowable

axial stress no design will be performed.

Section 9A1

9-29

Design for Flexure

Design procedure is same as that for IS 456. However while

designing following criteria are satisfied as per IS-13920:

1. The minimum grade of concrete shall preferably be M20. (Clause

5.2)

2. Steel reinforcements of grade Fe415 or less only shall be used.

(Clause 5.3)

3. The minimum tension steel ratio on any face, at any section, is

given by

min = 0.24fck/fy (Clause 6.2.1b)

The maximum steel ratio on any face, at any section, is given by max = 0.025 (Clause 6.2.2)

4. The positive steel ratio at a joint face must be at least equal to half

the negative steel at that face. (Clause 6.2.3)

5. The steel provided at each of the top and bottom face, at any

section, shall at least be equal to one-fourth of the maximum

negative moment steel provided at the face of either joint. (Clause

6.2.4)

Design for Shear

The shear force to be resisted by vertical hoops is guided by the

Clause 6.3.3 of IS 13920:1993 revision. Elastic sagging and

hogging moments of resistance of the beam section at ends are

considered while calculating shear force. Plastic sagging and

hogging moments of resistance can also be considered for shear

design if PLASTIC parameter is mentioned in the input file. (Refer

Table 8A1.1)


torsional moments. Procedure is same as that of IS 456.


Section 9A1

9-30

The following criteria are satisfied while performing design for

shear as per Cl. 6.3.5 of IS-13920:

The spacing of vertical hoops over a length of 2d at either end of

the beam shall not exceed

a) d/4

b) 8 times the diameter of the longitudinal bars

In no case this spacing is less than 100 mm.

The spacing calculated from above, if less than that calculated

from IS 456 consideration is provided.

Beam Design Output


reinforcement provided at 5 equally spaced sections along the

length of the beam. User has option to get a more detail output. All

beam design outputs are given in IS units. An example of

rectangular beam design output with the default output option

(TRACK 1.0) is presented below:

Section 9A1

9-31 ============================================================================

B E A M N O. 11 D E S I G N R E S U L T S

M20 Fe415 (Main) Fe415 (Sec.)

LENGTH: 3500.0 mm SIZE: 250.0 mm X 350.0 mm COVER: 30.0 mm

DESIGN LOAD SUMMARY (KN MET)

----------------------------------------------------------------------------

SECTION |FLEXTURE (Maxm. Sagging/Hogging moments)| SHEAR

(in mm) | P MZ MX Load Case | VY MX Load Case

----------------------------------------------------------------------------

0.0 | 0.00 0.00 0.00 4 | 17.67 0.00 4

| 0.00 -2.74 0.00 5 |

291.7 | 0.00 1.15 0.00 5 | 16.26 0.00 4

| 0.00 0.00 0.00 4 |

583.3 | 0.00 4.61 0.00 5 | 13.97 0.00 4

| 0.00 0.00 0.00 4 |

875.0 | 0.00 7.44 0.00 5 | 10.78 0.00 4

| 0.00 0.00 0.00 4 |

1166.7 | 0.00 9.41 0.00 5 | 6.69 0.00 4

| 0.00 0.00 0.00 4 |

1458.3 | 0.00 10.33 0.00 5 | 1.10 0.00 5

| 0.00 0.00 0.00 4 |

1750.0 | 0.00 9.98 0.00 5 | -3.60 0.00 5

| 0.00 0.00 0.00 4 |

2041.7 | 0.00 8.23 0.00 5 | -10.02 0.00 4

| 0.00 0.00 0.00 4 |

2333.3 | 0.00 5.21 0.00 5 | -15.00 0.00 4

| 0.00 0.00 0.00 4 |

2625.0 | 0.00 1.14 0.00 5 | -19.08 0.00 4

| 0.00 0.00 0.00 4 |

2916.7 | 0.00 0.00 0.00 4 | -22.27 0.00 4

| 0.00 -3.79 0.00 5 |

3208.3 | 0.00 0.00 0.00 4 | -24.57 0.00 4

| 0.00 -9.35 0.00 5 |

3500.0 | 0.00 0.00 0.00 4 | -25.97 0.00 4

| 0.00 -15.34 0.00 5 |

*** DESIGN SHEAR FORCE AT SECTION 0.0 IS 68.60 KN.

- CLAUSE 6.3.3 OF IS-

13920

*** DESIGN SHEAR FORCE AT SECTION 3500.0 IS 75.24 KN.

- CLAUSE 6.3.3 OF IS-

13920

----------------------------------------------------------------------------

SUMMARY OF REINF. AREA (Sq.mm)

----------------------------------------------------------------------------

SECTION 0.0 mm 875.0 mm 1750.0 mm 2625.0 mm 3500.0 mm

----------------------------------------------------------------------------

TOP 226.30 0.00 0.00 0.00 226.30

REINF. (Sq. mm) (Sq. mm) (Sq. mm) (Sq. mm) (Sq. mm)

BOTTOM 0.00 203.02 203.02 203.02 0.00

REINF. (Sq. mm) (Sq. mm) (Sq. mm) (Sq. mm) (Sq. mm)

----------------------------------------------------------------------------


----------------------------------------------------------------------------

SECTION 0.0 mm 875.0 mm 1750.0 mm 2625.0 mm 3500.0 mm

----------------------------------------------------------------------------

TOP 3-10í 2-10í 2-10í 2-10í 3-10í

REINF. 1 layer(s) 1 layer(s) 1 layer(s) 1 layer(s) 1 layer(s)

BOTTOM 2-12í 2-12í 2-12í 2-12í 2-12í

REINF. 1 layer(s) 1 layer(s) 1 layer(s) 1 layer(s) 1 layer(s)

SHEAR 2 legged 8í 2 legged 8í 2 legged 8í 2 legged 8í 2 legged 8í

REINF. @ 100 mm c/c @ 150 mm c/c @ 150 mm c/c @ 150 mm c/c @ 100 mm c/c

----------------------------------------------------------------------------

============================================================================


Section 9A1

9-32

9A1.5 Column Design

Columns are designed for axial forces and biaxial moments per IS

456:2000. Columns are also designed for shear forces as per

Clause 7.3.4. All major criteria for selecting longitudinal and

transverse reinforcement as stipulated by IS:456 have been taken

care of in the column design of STAAD. However following

clauses have been satisfied to incorporate provisions of IS 13920:

1. The minimum grade of concrete shall preferably be M20.

(Clause 5.2)

2. Steel reinforcements of grade Fe415 or less only shall be used.

(Clause 5.3)

3. The minimum dimension of column member shall not be less

than 200 mm. For columns having unsupported length

exceeding 4m, the shortest dimension of column shall not be

less than 300 mm. (Clause 7.1.2)

4. The ratio of the shortest cross-sectional dimension to the

perpendicular dimension shall preferably be not less than 0.4.

(Clause 7.1.3)

5. The spacing of hoops shall not exceed half the least lateral

dimension of the column, except where special confining

reinforcement is provided. (Clause 7.3.3)

6. Special confining reinforcement shall be provided over a

length lo from each joint face, towards mid span, and on either

side of any section, where flexural yielding may occur. The

length lo shall not be less than a) larger lateral dimension of

the member at the section where yielding occurs, b) 1/6 of

clear span of the member, and c) 450 mm. (Clause 7.4.1)

7. The spacing of hoops used as special confining reinforcement

shall not exceed ¼ of minimum member dimension but need

not be less than 75 mm nor more than 100 mm. (Clause 7.4.6)

Section 9A1

9-33

8. The area of cross-section of hoops provided are checked

against the provisions for minimum area of cross-section of

the bar forming rectangular, circular or spiral hoops, to be

used as special confining reinforcement. (Clause 7.4.7 and

7.4.8)








output is given in SI units. An example of a column design output

(with option TRACK 1.0) is given below. ============================================================================

C O L U M N N O. 3 D E S I G N R E S U L T S


LENGTH: 3000.0 mm CROSS SECTION: 350.0 mm X 400.0 mm COVER: 40.0 mm

** GUIDING LOAD CASE: 5 END JOINT: 2 SHORT COLUMN

DESIGN FORCES (KNS-MET)

-----------------------

DESIGN AXIAL FORCE (Pu) : 226.7

About Z About Y

INITIAL MOMENTS : 0.64 146.28

MOMENTS DUE TO MINIMUM ECC. : 4.53 4.53

SLENDERNESS RATIOS : - -

MOMENTS DUE TO SLENDERNESS EFFECT : - -

MOMENT REDUCTION FACTORS : - -

ADDITION MOMENTS (Maz and May) : - -

TOTAL DESIGN MOMENTS : 4.53 146.28

** GUIDING LOAD CASE: 5

Along Z Along Y

DESIGN SHEAR FORCES : 43.31 76.08

REQD. STEEL AREA : 3313.56 Sq.mm.

MAIN REINFORCEMENT : Provide 12 - 20 dia. (2.69%, 3769.91 Sq.mm.)

(Equally distributed)

CONFINING REINFORCEMENT : Provide 10 mm dia. rectangular ties @ 85 mm c/c

over a length 500.0 mm from each joint face towards

midspan as per Cl. 7.4.6 of IS-13920.

TIE REINFORCEMENT : Provide 10 mm dia. rectangular ties @ 175 mm c/c

SECTION CAPACITY (KNS-MET)

--------------------------

Puz : 2261.52 Muz1 : 178.71 Muy1 : 150.75

INTERACTION RATIO: 1.00 (as per Cl. 39.6, IS456:2000)

============================================================================

********************END OF COLUMN DESIGN RESULTS********************


Section 9A1

9-34




Table 9A1.1 Indian Concrete Design IS13920 Parameters

Parameter

Name


FYMAIN 415 N/mm2 Yield Stress for main reinforcing steel.



CLEAR 25 mm

40 mm

For beam members.

For column members







COLUMN DESIGN







Section 9A1

9-35


Parameter

Name








TORSION 0.0 A value of 0.0 means torsion to be considered in beam design.

A value of 1.0 means torsion to be neglected in beam design.


For TRACK = 0.0, output consists of reinforcement details at START, MIDDLE and END.

For TRACK = 1.0, critical moments are printed in addition to TRACK 0.0 output.

For TRACK = 2.0, required steel for intermediate sections defined by NSECTION are printed in addition to TRACK 1.0 output.

COLUMN DESIGN:

With TRACK = 0.0, reinforcement details are printed.

With TRACK = 1.0, column interaction analysis results are printed in addition to TRACK 0.0 output.


Section 9A1

9-36


Parameter

Name


With TRACK = 2.0, a schematic interaction diagram and intermediate interaction values are printed in addition to TRACK 1.0 output.

SPSMAIN 25 mm Minimum clear distance between main reinforcing bars in beam and column. For column centre to centre distance between main bars cannot exceed 300mm.

SFACE 0.0 Face of support location at start of beam. It is used to check against shear at the face of the support in beam design. The parameter can also be used to check against shear at any point from the start of the member.*

EFACE 0.0 Face of support location at end of beam. The parameter can also be used to check against shear at any point from the end of the member. (Note: Both SFACE and EFACE are input as positive numbers).*

ENSH 0.0 Perform shear check against enhanced shear strength as per Cl. 40.5 of IS456:2000.

ENSH = 1.0 means ordinary shear check to be performed ( no enhancement of shear strength at sections close to support)

For ENSH = a positive value(say x ), shear strength will be enhanced up to a distance x from the start of the member. This is used only when a span of a beam is subdivided into two or more parts. (Refer note after Table 8A.1 )

For ENSH = a negative value(say –y), shear strength will be enhanced up to a distance y from the end of the member. This is used only when a span of a beam is subdivided into two or more parts.(Refer note after Table 8A.1)

If default value (0.0) is used the program will calculate Length to Overall Depth ratio. If this ratio is greater than 2.5, shear strength will be enhanced at sections (<2d) close to support otherwise ordinary shear check will

Section 9A1

9-37


Parameter

Name


be performed.

RENSH 0.0 Distance of the start or end point of the member from its nearest support. This parameter is used only when a span of a beam is subdivided into two or more parts. (Refer note after Table 8A.1)

EUDL None Equivalent u.d.l on span of the beam. This load value must be the unfactored load on span. During design the load value is multiplied by a factor 1.2. If no u.d.l is defined factored shear force due to gravity load on span will be taken as zero. No elastic or plastic moment will be calculated. Shear design will be performed based on analysis result.(Refer note)

GLD None Gravity load number to be considered for calculating equivalent u.d.l on span of the beam, in case no EUDL is mentioned in the input. This loadcase can be any static loadcase containing MEMBER LOAD on the beam which includes UNI, CON, LIN and TRAP member loading. CMOM member loading is considered only when it is specified in local direction. FLOOR LOAD is also considered.

The load can be primary or combination load. For combination load only load numbers included in load combination is considered. The load factors are ignored. Internally the unfactored load is multiplied by a factor 1.2 during design.

If both EUDL and GLD parameters are mentioned in the input mentioned EUDL will be considered in design

Note :

No dynamic (Response spectrum, 1893, Time History) and moving load cases are considered.

CMOM member loading in global direction is


Section 9A1

9-38


Parameter

Name


not considered.

UMOM member loading is not considered.

PLASTIC 0.0 Default value calculates elastic hogging and sagging moments of resistance of beam at its ends.

A value of 1.0 means plastic hogging and sagging moments of resistance of beam to be calculated at its ends.

IPLM 0.0 Default value calculates elastic/plastic hogging and sagging moments of resistance of beam at its ends.

A value of 1.0 means calculation of elastic/plastic hogging and sagging moments of resistance of beam to be ignored at start node of beam. This implies no support exists at start node.

A value of -1.0 means calculation of elastic/plastic hogging and sagging moments of resistance of beam to be considered at start node of beam. . This implies support exists at start node.

A value of 2.0 means calculation of elastic/plastic hogging and sagging moments of resistance of beam to be ignored at end node of beam. This implies no support exists at end node.

A value of -2.0 means calculation of elastic/plastic hogging and sagging moments of resistance of beam to be considered at end node of beam. . This implies support exists at end node. **

IMB 0.0 Default value calculates elastic/plastic hogging and sagging moments of resistance of beam at its ends.

A value of 1.0 means calculation of

Section 9A1

9-39


Parameter

Name


elastic/plastic hogging and sagging moments of resistance of beam to be ignored at both ends of beam. This implies no support exist at either end of the member.

A value of -1.0 means calculation of elastic/plastic hogging and sagging moments of resistance of beam to be considered at both ends of beam. This implies support exist at both ends of the member.**

COMBINE 0.0 Default value means there will be no member combination.

A value of 1.0 means there will be no printout of sectional force and critical load for combined member in the output.

A value of 2.0 means there will be printout of sectional force for combined member in the output.

A value of 3.0 means there will be printout of both sectional force and critical load for combined member in the output. ***

HLINK Spacing of longitudinal bars measured to the

outer face

Longer dimension of the rectangular confining hoop measured to its outer face. It shall not exceed 300 mm as per Cl. 7.4.8. If hlink value as provided in the input file does not satisfy the clause the value will be internally assumed as the default one. This parameter is valid for rectangular column.

Bar combination has been introduced for detailing. Please refer section 8A1.6 for details.

* EFACE and SFACE command is not valid for member combination. ** IPLM and IMB commands are not valid for member combination. These commands are ignored for members forming physical member.


Section 9A1

9-40

*** The purpose of COMBINE command is the following:

1. If a beam spanning between two supports is subdivided into many sub-beams this parameter will combine them into one member. It can also be used to combine members to form one continuous beam spanning over more than two supports.

2. When two or more members are combined during design plastic or elastic moments will be calculated at the column supports. At all the intermediate nodes (if any) this calculation will be ignored. Please note that the program only recognizes column at right angle to the beam. Inclined column support is ignored.

3. It will calculate sectional forces at 13 sections along the length of the combined member.

4. It will calculate critical loads (similar to that of Design Load Summary) for all active load cases during design. Beams will be combined only when DESIGN BEAM command is issued. The following lines should be satisfied during combination of members:

1. Members to be combined should have same sectional properties if any single span between two column supports of a continuous beam is subdivided into several members.

2. Members to be combined should have same constants (E, Poi ratio, alpha, density and beta angle)

3. Members to be combined should lie in one straight line. 4. Members to be combined should be continuous. 5. Vertical members (i.e. columns) cannot be combined. 6. Same member cannot be used more than once to form two different

combined members. 7. The maximum number of members that can be combined into one

member is 299.

Section 9A1

9-41

Note: Sectional forces and critical load for combined member output will only be available when all the members combined are successfully designed in both flexure and shear. ENSH and RENSH parameters will have to be provided (as and when necessary) even if physical member has been formed. The following lines show a standard example for design to be

performed in IS 13920.

STAAD SPACE

UNIT METER MTON

JOINT COORDINATES

…………………………………..

MEMBER INCIDENCES

…………………………………..

MEMBER PROPERTY INDIAN

…………………………………..

CONSTANTS

…………………….

SUPPORTS

…………………….

DEFINE 1893 LOAD

ZONE 0.05 I 1 K 1 B 1

SELFWEIGHT

JOINT WEIGHT

……………………….

LOAD 1 SEISMIC LOAD IN X DIR

1893 LOAD X 1

LOAD 2 SEISMIC LOAD IN Z DIR

1893 LOAD Z 1

LOAD 3 DL

MEMBER LOAD

…… UNI GY -5

LOAD 4 LL


Section 9A1

9-42

MEMBER LOAD

……. UNI GY -3

LOAD COMB 5 1.5(DL+LL)

3 1.5 4 1.5

LOAD COMB 6 1.2(DL+LL+SLX)

1 1.2 3 1.2 4 1.2

LOAD COMB 7 1.2(DL+LL-SLX)

1 1.2 3 1.2 4 -1.2

LOAD COMB 8 1.2(DL+LL+SLZ)

2 1.2 3 1.2 4 1.2

LOAD COMB 9 1.2(DL+LL-SLZ)

2 1.2 3 1.2 4 -1.2

PDELTA ANALYSIS

LOAD LIST 5 TO 9


CODE IS13920

UNIT MMS NEWTON

FYMAIN 415 ALL

FC 20 ALL

MINMAIN 12 ALL

MAXMAIN 25 ALL

TRACK 2.0 ALL

*** Unfactored gravity load on members 110 to 112 is 8 t/m (DL+LL) i.e. 78.46 New/mm

EUDL 78.46 MEMB 110 TO 112

** Members to be combined into one physical member

COMBINE 3.0 MEMB 110 TO 112

*** Plastic moment considered

PLASTIC 1.0 MEMB 110 TO 112

DESIGN BEAM 110 TO 112

DESIGN COLUMN ………

END CONCRETE DESIGN

FINISH

Section 9A1

9-43

9A1.6 Bar Combination

Initially the program selects only one bar to calculate the number

of bars required and area of steel provided at each section along

the length of the beam. Now two bar diameters can be specified to

calculate a combination of each bar to be provided at each section.

The syntax for bar combination is given below.

START BAR COMBINATION MD1 <bar diameter> MEMB <member list> MD2 <bar diameter> MEMB <member list> END BAR COMBINATION

MD2 bar diameter should be greater than MD1 bar diameter. The

typical output for bar combination is shown below:

OUTPUT FOR BAR COMBINATION

----------------------------------------------------------------------------

| M A I N R E I N F O R C E M E N T |

----------------------------------------------------------------------------

SECTION | 0.0- 2166.7 | 2166.7- 6500.0 | 6500.0- 8666.7 |

| mm | mm | mm |

----------------------------------------------------------------------------

TOP | 6-20í + 1-25í | 2-20í + 1-25í | 2-20í |

| in 2 layer(s) | in 1 layer(s) | in 1 layer(s) |

Ast Reqd| 2330.22 | 1029.90 | 582.55 |

Prov| 2376.79 | 1119.64 | 628.57 |

Ld (mm) | 940.2 | 940.2 | 940.2 |

----------------------------------------------------------------------------

BOTTOM | 4-20í | 2-20í | 2-20í |

| in 1 layer(s) | in 1 layer(s) | in 1 layer(s) |

Ast Reqd| 1165.11 | 582.55 | 582.55 |

Prov| 1257.14 | 628.57 | 628.57 |

Ld (mm) | 940.2 | 940.2 | 940.2 |

----------------------------------------------------------------------------

The beam length is divided into three parts, two at its ends and one

at span. Ld gives the development length to be provided at the two

ends of each section.


Section 9A1

9-44

Sample example showing calculation of design shear force as per

Clause 6.3.3

For Beam No. 1 and 2

Section Width b 250 mm

Depth D 500 mm

Characteristic Strength of Steel fy 415 N/sq. mm Characteristic Strength of Concrete fck 20 N/sq. mm Clear Cover 25 mm Bar Diameter 12 mm Effective Depth d 469 mm Eudl w 6.5 N/sq. mm Length L 4000 mm Ast_Top_A 339.29 sq. mm Ast_Bot_A 226.19 sq. mm Ast_Top_B 226.19 sq. mm Ast_Bot_B 339.29 sq. mm

Section 9A1

9-45

Steps

Calculation of Simple Shear

Simple shear from gravity load on span =

Va = Vb = 1.2 * w * L / 2 = 15600N

Calculation of Moment Of Resistances Based On Area Of Steel Provided

Sagging Moment Of Resistance of End A Mu, as =

0.87 * fy * Ast_Bot_A * d * ( 1 - Ast_Bot_A * fy / b * d * fck)

= 36768130.05 N

Hogging Moment Of Resistance of End A Micah =

0.87 * fy * Ast_Top_A * d * ( 1 - Ast_Top_A * fy / b * d * fck)

= 54003057.45 N

Sagging Moment Of Resistance of End A Mu, bs =

0.87 * fy * Ast_Bot_B * d * ( 1 - Ast_Bot_B * fy / b * d * fck)

= 54003057.45 N

Hogging Moment Of Resistance of End A Mob =

0.87 * fy * Ast_Top_B * d * ( 1 - Ast_Top_B* fy / b * d * fck)

= 36768130.05 N

Calculation of Shear Force Due To Formation Of Plastic Hinge At Both Ends Of The Beam Plus The Factored Gravity Load On Span

FIG1: SWAY TO RIGHT

Vur,a = Va - 1.4 [ ( Mu,as + Mu,bh ) / L ] = -10137.69104 N Vur,b = Va + 1.4 [ ( Mu,as + Mu,bh ) / L ] = 41337.69104 N


Section 9A1

9-46

FIG2: SWAY TO LEFT

Vul,a = Va + 1.4 [ ( Mu,ah + Mu,bs ) / L ] = 53402.14022 N

Vul,b = Va - 1.4 [ ( Mu,ah + Mu,bs ) / L ] = - 22202.14022 N Design Shear Force Shear Force From Analysis At End A , Va,anl = 11.56 N Design Shear Force At End A, Vu,a = Max ( Va,anl, Vur,a, Vul,a) = 53402.14022 N

Shear Force From Analysis At End B , Vb,anl = -6.44 N Design Shear Force At End B, Vu,b = Max ( Vb,anl, Vur,b, Vul,b) = 41337.69104 N

For Beam No. 3

Section Width b 300 mm

Depth D 450 mm

Characteristic Strength of Steel fy 415 N/sq. mm

Characteristic Strength of Concrete fck 20 N/sq. mm

Clear Cover 25 mm

Bar Diameter 12 mm

Effective Depth d 419 mm

Eudl w 6.5 N/sq. mm

Length L 3000 mm

Ast_Top_A 226.19 sq. mm

Ast_Bot_A 339.29 sq. mm

Ast_Top_B 452.39 sq. mm

Ast_Bot_B 226.19 sq. mm

Section 9A1

9-47

Calculation of Simple Shear

Simple shear from gravity load on span =

Va = Vb = 1.2 * w * L / 2 = 11700N

Calculation of Moment Of Resistances Based On Area Of Steel Provided

Sagging Moment Of Resistance of End A Mu,as =

0.87 * fy * Ast_Bot_A * d * ( 1 - Ast_Bot_A * fy / b * d * fck)

= 48452983 N

Hogging Moment Of Resistance of End A Mu,ah =

0.87 * fy * Ast_Top_A * d * ( 1 - Ast_Top_A * fy / b * d * fck)

= 32940364.5 N

Sagging Moment Of Resistance of End A Mu,bs =

0.87 * fy * Ast_Bot_B * d * ( 1 - Ast_Bot_B * fy / b * d * fck)

= 32940364.5 N

Hogging Moment Of Resistance of End A Mu,bh =

0.87 * fy * Ast_Top_B * d * ( 1 - Ast_Top_B* fy / b * d * fck)

= 63326721.3 N

Calculation of Shear Force Due To Formation Of Plastic Hinge At Both

Ends Of The Beam Plus The Factored Gravity Load On Span

FIG1: SWAY TO RIGHT

Vur,a = Va - 1.4 [ ( Mu,as + Mu,bh ) / L ] = -40463.862 N Vur,b = Va + 1.4 [ ( Mu,as + Mu,bh ) / L ] = 63863.862 N


Section 9A1

9-48

Vul,a = Va + 1.4 [ ( Mu,ah + Mu,bs ) / L ] = 42444.3402 N

Vul,b = Va - 1.4 [ ( Mu,ah + Mu,bs ) / L ] = -15144.34 N Design Shear Force Shear Force From Analysis At End A , Va,anl = -10.31 N Design Shear Force At End A, Vu,a = Max ( Va,anl, Vur,a, Vul,a) = 42444.3402 N

Shear Force From Analysis At End B , Vb,anl = -23.81 N Design Shear Force At End B, Vu,b = Max ( Vb,anl, Vur,b, Vul,b) = 63863.862 N

9-49

Steel Design Per IS800

9B.1 Design Operations

STAAD contains a broad set of facilities for designing structural

members as individual components of an analyzed structure. The

member design facilities provide the user with the ability to carry

out a number of different design operations. These facilities may

be used selectively in accordance with the requirements of the

design problem. The operations to perform a design are:


design.


selection.


values.

Specify whether to perform member selection by optimization.


depending upon the design requirements. The entire ISI steel

section table is supported. Section 8B.13 describes the

specification of steel sections.

Section 9B


Section 9B

9-50



implementation of Indian Standard code of practice (IS:800-1984)

for structural steel design in STAAD. The design philosophy and

procedural logistics for member selection and code checking are

based upon the principles of allowable stress design. Two major

failure modes are recognized: failure by overstressing, and failure

by stability considerations. The flowing sections describe the

salient features of the allowable stresses being calculated an d the

stability criteria being used. Members are proportioned to resist

the design loads without exceeding the allowable stresses and the

most economic section is selected on the basis of least weight

criteria. The code checking part of the program checks stability

and strength requirements and reports the critical loading

condition and the governing code criteria. It is generally assumed

that the user will take care of the detailing requirements like

provision of stiffeners and check the local effects such as flange

buckling and web crippling.

9B.3 Allowable Stresses


the allowable stress design method as per IS:800 (1984). It is a

method for proportioning structural members using design loads

and forces, allowable stresses, and design limitations for the

appropriate material under service conditions. It would not be

possible to describe every aspect of IS:800 in this manual. This

section, however, will discuss the salient features of the allowable

stresses specified by IS:800 and implemented in STAAD.

Appropriate sections of IS:800 will be referenced during the

discussion of various types of allowable stresses.

Section 9B

9-51

9B.3.1 Axial Stress

Tensile Stress

The allowable tensile stress, as calculated in STAAD as per IS:800

is described below.

The permissible stress in axial tension, at in MPa on the net

effective area of the sections shall not exceed

at = 0.6 fy

where,


Compressive Stress

Allowable compressive stress on the gross section of axially

loaded compression members shall not exceed 0.6fy nor the

permissible stress ac calculated based on the following formula:

(Clause: 5.1.1)

f f

nccf

nyf

0 6.

[( ) ( ) ]

where,

ac = Permissible stress in axial compression, in Mpa


fcc = Elastic critical stress in compression = 2 E/2

E = Modulus of elasticity of steel, 2 X 105 Mpa

=l/r = Slenderness ratio of the member, ratio of the effective

length to appropriate radius of gyration

n = A factor assumed as 1.4.


Section 9B

9-52

9B.3.2 Bending Stress

The allowable bending stress in a member subjected to bending is

calculated based on the following formula: (Clause: 6.2.1)

bt or bc = 0.66 fy

where,

bt = Bending stress in tension

bc = Bending stress in compression

fy = Yield stress of steel, in MPa

For an I-beam or channel with equal flanges bent about the axis of

maximum strength (z-z axis), the maximum bending compressive

stress on the extreme fibre calculated on the effective section shall

not exceed the values of maximum permissible bending compressive

stress. The maximum permissible bending compressive stress shall be

obtained by the following formula: (Clause: 6.2.2)

6.2.3) :(Clause

])f y(n

)f cb(n

[

1/n

f yf cb0.66σbc

where,


n = A factor assumed as 1.4.

fcb = Elastic critical stress in bending, calculated by the

following formula:

f k X k Yc

c [ ]

Section 9B

9-53

where,

X YIT

r DMP

yr 1

1

20 1 Y =

26.5x10

( / )

k1 = a coefficient to allow for reduction in thickness or

breadth of flanges between points of effective lateral

restraint and depends on , the ratio of the total area of

both flanges at the point of least bending moment to the

corresponding area at the point of greatest bending

moment between such points of restraint.

k2 = a coefficient to allow for the inequality of flanges, and

depends on , the ratio of the moment of inertia of the

compression flange alone to that of the sum of the moment

of the flanges each calculated about its own axis parallel to

the y-yaxis of the girder, at the point of maximum bending

moment.

1 = effective length of compression flange

ry = radius of gyration of the section about its axis of

minimum strength (y-y axis)

T = mean thickness of the compression flange, is equal to the

area of horizontal portion of flange divided by width.

D = overall depth of beam

c1 ,c2 = respectively the lesser and greater distances from the

section neutral axis to the extreme fibres.

9B.3.3 Shear Stress

Allowable shear stress calculations are based on Section 6.4 of IS:800 .

For shear on the web, the gross section taken into consideration consist

of the product of the total depth and the web thickness. For shear

parallel to the flanges, the gross section is taken as 2/3 times the total

flange area.


Section 9B

9-54

9B.3.4 Combined Stress

Members subjected to both axial and bending stresses are

proportioned accordingly to section 7 of IS:800. All members

subject to bending and axial compression are required to satisfy

the equation of Section 7.1.1.(a) for intermediate points, and

equation of Section 7.1.1.(b) for support points.

For combined axial tension and bending the equation of Section

7.1.2. is required to be satisfied.

Cm coefficients are calculated according to the specifications of

Section 7.1.3. information regarding occurrence of sidesway can

be provided through the use of parameters SSY and SSZ. In the

absence of any user provided information, sidesway will be

assumed.


In STAAD implementation of IS:800, the user is allowed complete

control of the design process through the use of design parameters.

Available design parameters to be used in conjunction with IS:800

are listed in Table 7B.1 of this section along with their default

values and applicable restrictions. Users should note that when the

TRACK parameter is set to 1.0 and use in conjunction with this

code, allowable bending stresses in compression (FCY & FCZ),

tension (FTY & FTZ), and allowable shear stress (FV) will be

printed out in Member Selection and Code Check output in Mpa.

When TRACK is set to 2.0, detailed design output will be

provided.

9B.5 Stability Requirements


against the appropriate maximum values. Section 3.7 of IS:800

Section 9B

9-55

summarizes the maximum slenderness ratios for different types of

members. In STAAD implementation of IS:800, appropriate

maximum slenderness ratio can be provided for each member. If

no maximum slenderness ratio is provided, compression members

will be checked against a maximum value of 180 and tension

members will be checked against a maximum value of 400.

9B.6 Truss Members

As mentioned earlier, a truss member is capable of carrying only

axial forces. So in design no time is wasted in calculating bending

or shear stresses, thus reducing design time considerably.

Therefore, if there is any truss member in an analysis (like bracing

or strut, etc.), it is wise to declare it as a truss member rather than

as a regular frame member with both ends pinned.

9B.7 Deflection Check

This facility allows the user to consider deflection as a criteria in

the CODE CHECK and MEMBER SELECTION processes. The

deflection check may be controlled using three parameters which

are described in Table 7B.1. Note that deflection is used in

addition to other strength and stabil ity related criteria. The local

deflection calculation is based on the latest analysis results.

9B.8 Code Checking



requirements. The code checking is based on the IS:800 (1984)

requirements. Forces and moments at specified sections of the

members are utilized for the code checking calculations. Sections

may be specified using the BEAM parameter or the SECTION

command. If no sections are specified, the code checking is based

on forces and moments at the member ends.


Section 9B

9-56


FAILed. In addition, the critical condition (applicable IS:800

clause no.), governing load case, location (distance from the start)

and magnitudes of the governing forces and moments are also

printed out.




select the most economical section, that is, the lightest section,


selected will be of the same type (I-Section, Channel etc.) as


performed with all types of steel sections listed in Section 7B.13

and user provided tables. Selection of members, whose properties

are originally provided from user specified table, will be limited to

sections in the user provided table. Member selection can not be

performed on members whose cross sectional properties are

specified as PRISMATIC.








9B.10 Member Selection By Optimization

Steel section selection of the entire structure may be optimized.

The optimization method utilizes a state-of-the -art numerical

technique which requires automatic multiple analysis. The user

may start without a specifically designated section. However, the

section profile type (BEAM, COLUMN, CHANNEL, ANGLE etc.)

must be specified using the ASSIGN command (see Chapter 6).

Section 9B

9-57

The optimization is based on member stiffness contributions and

corresponding force distributions. An optimum member size is

determined through successive analysis/design iterations. This

method requires substantial computer time and hence should be

used with caution.



result in a tabulated fashion. The items in the output table are


a) MEMBER refers to the member number for which the design

is performed

b) TABLE refers to the INDIAN steel section name which has

been checked against the steel code or has been selected.

c) RESULT prints whether the member has PASSED or FAILed.

If the RESULT is FAIL, there will be an asterisk (*) mark in

front of the member number.

d) CRITICAL COND refers to the section of the IS:800 code


e) RATIO prints the ratio of the actual stresses to allowable

stresses for the critical condition. Normally a value of 1.0 or

less will mean the member has passed.

f) LOADING provides the load case number which governs the

design.

g) FX, MY and MZ provide the axial force, moment in local y-

axis and moment in local z-axis respectively. Although

STAAD does consider all the member forces and moments

(except torsion) to perform design, only FX,MY and MZ are

printed since they are the ones which are of interest , in most

cases.


Section 9B

9-58

h) LOCATION specifies the actual distance from the start of the

member to the section where design forces govern.

i) If the parameter TRACK is set to 1.0, the program will block

out part of the table and will print allowable bending stresses

in compression (FCY & FCZ) and tension (FTY & FTZ),

allowable axial stress in compression (FA), and allowable

shear stress (FV). When the parameter TRACK is set to 2.0

for all members parameter code values are as shown in Fig

8B.1.

STAAD.Pro CODE CHECKING - (ISA ) ***********************

|---------------------------------------------------------------------------|

| Y PROPERTIES |

|************* | IN CM UNIT |

| * |=============================| ===|=== ------------ |

|MEMBER 7 * | | | AX = 72.4 |

| * | ST ISLB400 | | --Z AY = 32.0 |

|DESIGN CODE * | | | AZ = 27.5 |

| IS-800 * =============================== ===|=== SY = 86.8 |

| * SZ = 965.3 |

| * |<---LENGTH (ME= 3.00 --->| RY = 3.1 |

|************* RZ = 16.3 |

| |

| 104.6( KN-METR) |

|PARAMETER |L1 STRESSES |

|IN NEWT MM | IN NEWT MM|

|--------------- + -------------|

| KL/R-Y= 95.4 | FA = 84.8 |

| KL/R-Z= 18.4 + fa = 1.6 |

| UNL = 3000.0 | FCZ = 116.6 |

| C = 400.0 + FTZ = 165.0 |

| CMY = 0.85 | FCY = 165.0 |

| CMZ = 0.85 + FTY = 165.0 |

| FYLD = 249.9 | L3 fbz = 108.4 |

| NSF = 0.9 +---+---+---+---+---+---+---+---+---+---| fby = 0.0 |

| DFF = 325.0 92.7 FV = 100.0 |

| dff = 4383.0 ABSOLUTE MZ ENVELOPE |

| (WITH LOAD NO.) |

| |

| MAX FORCE/ MOMENT SUMMARY ( KN-METR) |

| ------------------------- |

| |

| AXIAL SHEAR-Y SHEAR-Z MOMENT-Y MOMENT-Z |

| |

| VALUE -23.7 61.3 0.0 0.0 104.6 |

| LOCATION 0.0 0.0 0.0 0.0 0.0 |

| LOADING 3 1 0 0 1 |

| |

|***************************************************************************|

|* *|

|* DESIGN SUMMARY ( KN-METR) *|

|* -------------- *|

|* *|

|* RESULT/ CRITICAL COND/ RATIO/ LOADING/ *|

| FX MY MZ LOCATION |

| ====================================================== |

| PASS IS-7.1.2 0.667 1 |

| 9.62 T 0.0 -104.6 0.00 |

| |

| DEFLECTION * PASS |

| RATIO: 0.074 LOADING: 3 LOCATION: 0.67 |

|* *|

|***************************************************************************|

Section 9B

9-59

9B.12 Indian Steel Table

This is an important feature of the program since the program will

read section properties of a steel member directly from the latest

ISI steel tables (as published in ISI-800). These properties are

stored in memory corresponding to the section designation (e.g.

ISMB250, etc.). If called for, the properties are also used for

member design. Since the shear areas are built in to these tables,

shear deformation is always considered for these members.

Almost all ISI steel tables are available for input. A complete


may be obtained using the tools of the graphical user interface.

Following are the descriptions of all the types of sections

available:

Rolled Steel Beams (ISJB, ISLB, ISMB and ISHB).

All rolled steel beam sections are available the way they are

designated in the ISI handbook., e.g. ISJB225, ISWB400, etc.

20 TO 30 TA ST ISLB325

NOTE:

In case of two identical beams, the heavier beam is designated

with an „A” on the end., e.g. ISHB400 A, etc.

1 TO 5 TA ST ISHB400A


Section 9B

9-60

Rolled Steel Channels (ISJC, ISLC and ISMC)

All these shapes are available as listed in ISI section handbook.

Designation of the channels are per the scheme used by ISI.

10 TO 20 BY 2 TA ST ISMC125

12 TA ST ISLC300

Double Channels



specify a double channel, e.g. D ISJC125, D ISMC75 etc.

21 22 24 TA D ISLC225

Rolled Steel Angles

Both rolled steel equal angles and unequal angles are available for

use in the STAAD implementation of ISI steel tables. The

following example with explanations will be helpful in

understanding the input procedure:

ISA 150 X 75 X 8 Angle symbol Thickness in mm Long leg length in mm Short leg length in mm

At present there is no standard way to define the local y and z axes

for an angle section. The standard section has local axis system as

illustrated in Fig.2.4 of this manual. The standard angle is

specified as:

51 52 53 TA ST ISA60X60X6

Section 9B

9-61

This specification has the local z-axis ( i.e., the minor axis

corresponding to the V-V axis specified in the steel tables. Many

engineers are familiar with a convention used by some other

programs in which the local y-axis is the minor axis. STAAD

provides for this convention by accepting the command:

54 55 56 TA RA ISA50X30X6 (RA denotes reverse angle)

Double Angles



of the angle size. In case of an equal angle either LD or SD will


14 TO 20 TA LD ISA50X30X5 SP 1.5

23 27 TA SD ISA75X50X6

Rolled Tees (ISHT, ISST, ISLT and ISJT)

All the rolled tee sections are available for input as they are

specified in the ISI handbook. Following example illustrates the

designated method.

1 2 5 8 TA ST ISNT100

67 68 TA ST ISST250


To designate circular hollow sections from ISI tables, use PIP


section in mm omitting the decimal section of the value provided

for diameter. Following example will illustrate the designation.


Section 9B

9-62

10 15 TA ST PIP 213.2

(Specifies a 213 mm dia. pipe with 3.2 mm wall thickness)

Circular pipe sections can also be specified by providing the


1 TO 9 TA ST PIPE OD 25.0ID 20.0

(specifies a pipe with outside dia. of 25 and inside dia. of 20

in current length units)




Designation of tubes from the ISI steel table is illustrated below. TUB 400 200 12.5 Tube Symbol Thickness in mm Height in mm Width in mm Example:

15 TO 25 TA ST TUB 160808



6 TA ST TUBE DT 8.0 WT 6.0 TH 0.5 is a tube that has a height

of 8, a width of 6, and a wall thickness of 0.5.

Section 9B

9-63



Plate And Angle Girders (With Flange Plates)

All plate and angle grinders (with flange plates) are available as

listed in ISI section handbook. The following example with

explanations will be helpful in understanding the input procedure.

I 1000 12 A 400 12

A F

B E

C D

A Plate and angle girder symbol.

B Web plate width in mm.

C Web plate thickness in mm.

D Flange angle (Flange angle key below):

E Flange plate width in mm.

F Flange plate thickness in mm.

SYMBOL ANGLE(A X B X t)(all in mm)

A 150X150X18

B 200X100X15

C 200X150X18

E 200X200X18


Section 9B

9-64

SINGLE JOIST WITH CHANNELS AND PLATES ON THE

FLANGES TO BE USED AS GIRDERS

All single joist with channel and plates on the flanges to be used

as girders are available as listed in ISI section handbook. The

following example with explanations will be helpful in

understanding the input procedure.

IW 450 350 X 10 20

A E

B D

C

A Joist Designation: IW450=ISWB450

B Top flange channel designation:

350=ISMC350

C Constant (always X).

D Top flange plate thickness in mm.

NOTE: D is 0 for no plate.

E Bottom flange plate thickness in mm.

NOTE:

The heavier ISWB600 has been omitted, since the lighter

ISWB600 is more efficient.

Section 9B

9-65




Table 9B.1 Indian Steel Design - IS : 800 Parameters

Parameter

Name


KY 1.0 K value in local y-axis. Usually, this is minor axis.

KZ 1.0 K value in local z-axis. Usually, this is major axis.

LY Member Length Length in local y-axis to calculate slenderness ratio.

LZ Member Length Same as above except in local z-axis (major).

FYLD 250 MPA

(36.25 KSI) Yield strength of steel.


UNL Member Length Unsupported length for calculating allowable bending stress.

UNF 1.0 Same as above provided as a fraction of actual member length.



CMY

CMZ

0.85 for sidesway and

calculated for no sidesway


MAIN 180 (Comp. Memb.)

Allowable Kl/r for slenderness calculations for compression members.

TMAIN 400 (Tension Memb)

Allowable Kl/r for slenderness calculations for tension members.

TRACK 0.0

0.0 = Suppress critical member stresses 1.0 = Print all critical member stresses 2.0 = Print expanded output. If there is

deflection check it will also print the governing load case number for deflection check whenever critical condition for design is not DEFLECTION. (see fig.8B.1)


Section 9B

9-66

Table 9B.1 Indian Steel Design - IS : 800 Parameters

Parameter

Name





BEAM 3.0

0.0 = design only for end moments and those at locations specified by the SECTION command.

1.0 = calculate section forces at twelfth points along the beam, design at each intermediate location and report the critical location where ratio is maximum.

PROFILE - Search for the lightest section for the profile mentioned.

DFF None







NOTES:





"Deflection Length" may be different. For example, refer to









Section 9B

9-67

D = Maximum local deflection for members1 2 and 3.

D

1

2 3

4

1

2 3


DFF 300. ALL

DJ1 1 ALL

DJ2 4 ALL

2) If DJ1 and DJ2 are not used, "Deflection Length" will default





9B.13 Column With Lacings And Battens

For columns with large loads it is desirable to build rolled sections

at a distance and inter-connect them. The joining of element

sections is done by two ways:

a) Lacing and b) Batten

Double channel sections (back-to-back and face-to-face) can be

joined either by lacing or by batten plates having rivetted or

welded connection.

Table 8B.2 gives the parameters that are required for Lacing or

batten design. These parameters will have to be provided in unit

NEW MMS along with parameters defined in Table 9B.1.


Section 9B

9-68




Table 9B.2 Indian Concrete Design IS800 Parameters

Parameter

Name


CTYPE 1 Type of joining

CTYPE = 1 implies single lacing with rivetted connection

CTYPE = 2 implies double lacing with rivetted connection

CTYPE = 3 implies single lacing with welded connection

CTYPE = 4 implies double lacing with welded connection

CTYPE = 5 implies batten with rivetted connection

CTYPE = 6 implies batten with welded connection

THETA 50 degree Angle of inclination of lacing bars. It should lie between 40 degree and 70 degree.

DBL 20 mm Nominal diameter of rivet

FVB 100 N/mm2 Allowable shear stress in rivet

FYB 300 N/mm2 Allowable bearing stress in rivet

WMIN 6 mm Minimum thickness of weld

WSTR 108 N/mm2 Allowable welding stress

EDIST 32 mm (Rivetted Connection)

25 mm (Welded Connection)

Edge Distance

Section 9B

9-69

Table 9B.2 Indian Concrete Design IS800 Parameters

Parameter

Name


DCFR 0.0 0.0 implies double channel back-to-back.

1.0 Implies double channel face-to-face.

This parameter is used when member properties are defined through user provided table using GENERAL option.

COG 0.0 mm Centre of gravity of the channel. This parameter is used when member properties are defined through user provided table using GENERAL option.

SPA 0.0 mm Spacing between double channels. This parameter is used when member properties are defined through user provided table using GENERAL option.


Section 9B

9-70

9-71




implementation of Indian Standard code of practice (IS:802-1995 –

Part 1) for structural steel design for overhead transmission line

towers in STAAD. The design philosophy and procedural logistics

for member selection and code checking are based upon the

principles of allowable stress design. Two major failure modes are

recognized: failure by overstressing, and failure by stability

considerations. The flowing sections describe the salient features

of the allowable stresses being calculated and the stability criteria

being used. Members are proportioned to resist the design loads

without exceeding the allowable stresses and the most economic

section is selected on the basis of least weight criteria. The code

checking part of the program checks stability and strength

requirements and reports the critical loading condition and the

governing code criteria.

9C.2 Allowable Stresses


the allowable stress design method as per IS:802 (1995). It is a



appropriate material under service conditions.

This section discusses the salient features of the allowable stresses

specified by IS:802 and implemented in STAAD.

Section 9C


Section 9C

9-72

9C.2..1 Axial Stress

Tensile Stress

The allowable tensile stress, as calculated in STAAD as per IS:802

is described below.

The estimated tensile stresses on the net effective sectional area in

various members, multiplied by the appropriate factor of safety

shall not exceed minimum guaranteed yield stress of the material.

Thus, the permissible stress in axial tension, at in MPa on the net

effective area of the sections shall not exceed

at = fy

where,


Compressive Stress

The estimated compressive stresses in various members multiplied

by the appropriate factor of safety shall not exceed the value given

by the formulae described below.

Condition 1: If

yFt

b

t

b 210

lim

CCr/KL

Stress Fa= yFCc

r/KL

2

11

2

N/mm2

CCr/KL

Section 9C

9-73

Stress Fa = 2

2

/ rKL

E N/mm2

Condition 2: If

lim

t

b

t

b

yF

378 when Fy is the N/mm2

formulae given in condition 1 shall be used substituting for Fy the

value Fcr given by:

Fcr = y

lim

F

t

b

t

b677.0

677.1

Condition 3:

t

b>

yF

378when Fy is the N/mm2 formulae given in

condition 1 shall be used substituting for Fy the value Fcr given by

Fcr = 2

t

b

65550

In which CC =

yF

E2

where,

Fa = allowable unit stress in compression, Mpa

Fy = minimum guaranteed yield stress of the material, Mpa

K = restraint factor,

L = unbraced length of the compression member in cm, and

R = appropriate radius of gyration in cm.

E = modulus of elasticity of steel in N/mm2


Section 9C

9-74

r

KL = largest effective slenderness ratio of any unbraced segment

of the member,

b = distance from edge of the fillet to the extreme fibre in mm, and

t = thickness of flange in mm.

Note : The maximum permissible value of b/t for any type of steel

shall not exceed 25.

9C.3 Stability Requirements


against the appropriate maximum values. Following are the default

values used in STAAD:

Compression Members:

Members Slenderness

value

Leg Members, ground wire peak member and lower

members of cross arms in compression 120

Other members carrying computed stress 200

Redundant members and those carrying nominal

stresses 250

Section 9C

9-75

Slenderness ratios of compression members are determined as

follows:

If ELA number given in the input for any particular member is

such that condition for L/r ratio to fall within the specified range

is not satisfied, STAAD goes on by the usual way of finding

slenderness ratio using K*L/r formula.

ELA NO.

Type of members

Value of KL/r

1 Leg sections or joint members bolted

at connections in both faces

L/r

2 Members with concentric loading at

both ends of the unsupported panel

with values of L/r up to and

including 120

L/r

3 Member with concentric loading at

one end and normal eccentricities at

the other end of the unsupported

panel for value of L/r up to and

including 120

30 + 0.75L/r

4 Members with normal framing

eccentricities at both ends of the

unsupported panel for values of L/r

up to and including 120

60 + 0.5L/r

5 Member unrestrained against

rotation at both ends of the

unsupported panel for value of L/r

from 120 to 200

L/r

6 Members partially restrained against

rotation at one end of the


over 120 and up to and including 225

28.6 + 0.762L/r

7 Members partially restrained against

rotation at both ends of the


over 120 and up to and including 250

46.2 + 0.615L/r


Section 9C

9-76

Tension Members:

Slenderness ratio KL/r of a member carrying axial tension only,

shall not exceed 400.

9C.4 Minimum Thickness Requirement

As per Clause7.1 of IS: 802-1995 minimum thickness of different

tower members shall be as follows:

Members Minimum Thickness, mm

Galvanized Painted

Leg Members, ground wire peak

member and lower members of

cross arms in compression

5 6

Other members

4 5

9C.5 Code Checking



requirements. The code checking is based on the IS:802 (1995)

requirements. Axial forces at two ends of the members are utilized

for the code checking calculations.



location (distance from the start) and magnitudes of the governing

forces are also printed out. Using TRACK 9 option calculation

steps are also printed.

Section 9C

9-77

9C.5.1 Design Steps

The following are the steps followed in member design.

Step 1

Thickness of the member (maximum of web and flange

thicknesses) is checked against minimum allowable thickness,

depending upon whether the member is painted or galvanised.

Step 2

If the minimum thickness criterion is fulfilled, the program

determines whether the member is under compression or tension

for the loadcase under consideration. Depending upon whether the

member is under tension or compression the slenderness ratio of

the member is calculated. This calculated ratio is checked against

allowable slenderness ratio.

Step 3

If the slenderness criterion is fulfilled check against allowable

stress is performed. Allowable axial and tensile stresses are

calculated. If the member is under tension and there is no user

defined net section factor (NSF), the net section factor is

calculated by the program itself (Refer Section 8C.10). Actual

axial stress in the member is calculated. The ratio for actual stress

to allowable stress, if less than 1.0 or user defined value, the

member has passed the check.

Step 4

Number of bolts required for the critical loadcase is calculated.


Section 9C

9-78

9C.6 Member Selection



select the most economical section, that is, the lightest section,


selected will be of the same type (either angle or channel) as


performed with all angle or channel sections and user provided

tables. Selection of members, whose properties are originally

provided from user specified table, will be limited to sections in

the user provided table.








9C.7 Member Selection by Optimization

Steel section selection of the entire structure may be optimized .

The optimization method utilizes a state-of-the -art numerical

technique which requires automatic multiple analysis. The

optimization is based on member stiffness contributions and

corresponding force distributions.

An optimum member size is determined through successive

analysis/design iterations. This method requires substantial

computer time and hence should be used with caution.

Section 9C

9-79

9C.8 Tabulated Results of Steel Design

DETAILS OF CALCULATION

----------------------

CHECK FOR MINIMUM THICKNESS

---------------------------

TYPE : GALVANISED

MIN. ALLOWABLE THICKNESS : 5.0 MM

ACTUAL THICKNESS : 10.0 MM

RESULT : PASS


Section 9C

9-80

CHECK FOR SLENDERNESS RATIO

---------------------------

VALUE OF L/r : 90.16

EQN. USED TO FIND KL/r : 60.0 + 0.5*L/r

ACTUAL VALUE OF KL/r : 105.08

ALLOWABLE KL/r : 120.00

RESULT : PASS

CALCULATION OF ALLOWABLE STRESS

--------------------------------

CRITICAL CONDITION : COMPRESSION

Cc : sqrt(2*3.141592*3.141592*E/fy) : 127.22

b : LENGTH OF LEG - WEB THICKNESS - ROOT RADIUS

: 150.0 - 10.0 - 11.0 : 129.0 MM

(b/t)lim : 210/sqrt(fy) : 13.28

(b/t)cal : 12.90

(b/t)cal <= (b/t)lim AND KL/r <= Cc

ALLOWABLE AXIAL COMP. STRESS : (1 -0.5*(KL/r/Cc)*(KL/r/Cc))*fy :

164.72 MPA

CHECK AGAINST PERMISSIBLE STRESS

--------------------------------

DESIGN AXIAL FORCE : 250000.00 N

ACTUAL AXIAL COMP. STRESS : 250000.00 / 2552.0 : 97.96 MPA

RESULT : PASS

BOLTING

-------

BOLT DIA : 16 MM

SHEARING CAP : 20.11 KN

BEARING CAP : 38.40 KN

BOLT CAP : 20.11 KN

NO. OF BOLTS REQD. : 13

Section 9C

9-81

9C.9 Parameter Table for IS 802




Table 9C.1 Indian Steel Design - IS 802 Parameters

Parameter

Name




LY Member Length Unbraced length in local z-axis to calculate slenderness ratio.

LZ Member Length Unbraced length in local z-axis to calculate slenderness ratio.

FYLD 250 MPA Yield Strength of steel

MAIN 1.0 Type of member to find allowable Kl/r for slenderness calculations for members.

1.0 = Leg, Ground wire peak and lower members of cross arms in compression (KL/r = 120)

2.0 = Members carrying computed stress (KL/r = 200)

3.0 = Redundant members and members carrying nominal stresses (KL/r = 250)

4.0 = Tension members (KL/r = 400)

10.0 = Do not perform KL/r check

Any value greater than 10.0 indicates user defined allowable KL/r ratio. For this case KY and KZ values are must to find actual KL/r ratio of the member.




Section 9C

9-82


Parameter

Name


TRACK 0.0 0.0 = Suppress critical member stresses

1.0 = Print all critical member stresses

2.0 = Print expanded output.

9.0 = Print design calculations along with expanded output.

LEG 1.0 This parameter is meant for plain angles.

0.0 = indicates the angle is connected by shorter leg

1.0 = indicates the angle is connected by longer leg

ELA 1.0 This parameter indicates what type of end conditions is to be used. Refer Section 8C.3.

NSF 1.0 Net section factor for tension members

CNSF 0.0 This parameter indicates whether user has defined NSF or the program will calculate it.

0.0 = User has defined NSF

1.0 = Program has to calculate it

DANGLE 0.0 This parameter indicates how the pair of angles are connected to each other. This is required to find whether the angle is in single or double shear and the net section factor.

0.0 = Double angle placed back to back and connected to each side of a gusset plate

1.0 = Pair of angle placed back-to-back connected by only one leg of each angle to the same side of a gusset plate�

DBL 12 mm Diameter of bolt for calculation of number of bolts and net section factor.

FVB 218 MPA Allowable shear stress in bolt

FYB 436 MPA Allowable bearing stress in bolt

Section 9C

9-83


Parameter

Name


GUSSET 5 mm Thickness of gusset plate.

Minimum of the thicknesses of the gusset plate and the leg is used for calculation of the capacity of bolt in bearing

NHL 0.0 mm Deduction for holes.

Default value is one bolt width plus 1.5 mm. If the area of holes cut by any straight, diagonal or zigzag line across the member is different from the default value, this parameter is to be defined.

9C.10 Calculation of Net Section Factor

The procedure for calculating net section factor for angle section is

described below.

Single angle connected by only one leg

Anet = A1 + A2 x K1

Where, A1 = net cross-sectional area of the connected leg

A2 = gross cross-sectional area of the unconnected leg

And K1 = A2 A13

A13

x

x

The area of a leg of an angle = Thickness of angle x (length of leg

– 0.5x thickness of leg)


Section 9C

9-84

Pair of angles placed back-to-back connected by only one leg of

each angle to the same side of a gusset plate

Anet = A1 + A2 x K1

Where A1 = net cross-sectional area of the connected leg

A2 = gross cross-sectional area of the unconnected leg

And K1 = A2 A15

A15

x

x

The area of a leg of an angle = Thickness of angle x (length of leg

– 0.5x thickness of leg)

Double angles placed back to back and connected to each side

of a gusset plate

Anet = gross area – deduction for holes

Net Section Factor

For angle section it is the ratio of the net effective area, Anet to the

gross area.

For channel section net section factor is taken to be 1.0.

Section 9C

9-85

9C.11 Example Problem No. 28

A transmission line tower is subjected to different loading

conditions. Design some members as per IS-802 and show detailed

calculation steps for the critical loading condition.

Given: End Condition = Members with normal framing

eccentricities at both ends of the unsupported panel for

values of L/r up to and including 120

Diameter of the bolt = 16 mm

Thickness of the gusset plate = 8 mm

Net Section Factor is to be calculated.


Section 9C

9-86

STAAD TRUSS

INPUT WIDTH 79

UNIT METER KN

JOINT COORDINATES

1 3 0 3; 2 1.2 27 1.2; 3 2.8 3 2.8; 4 2.6 6 2.6; 5 2.4 9 2.4; 6 2.2 12 2.2;

7 2 15 2; 8 1.8 18 1.8; 9 1.6 21 1.6; 10 1.4 24 1.4; 11 -3 0 3; 12 -1.2 27 1.2;

13 -2.8 3 2.8; 14 -2.6 6 2.6; 15 -2.4 9 2.4; 16 -2.2 12 2.2; 17 -2 15 2;

18 -1.8 18 1.8; 19 -1.6 21 1.6; 20 -1.4 24 1.4; 21 3 0 -3; 22 1.2 27 -1.2;

23 2.8 3 -2.8; 24 2.6 6 -2.6; 25 2.4 9 -2.4; 26 2.2 12 -2.2; 27 2 15 -2;

28 1.8 18 -1.8; 29 1.6 21 -1.6; 30 1.4 24 -1.4; 31 -3 0 -3; 32 -1.2 27 -1.2;

33 -2.8 3 -2.8; 34 -2.6 6 -2.6; 35 -2.4 9 -2.4; 36 -2.2 12 -2.2; 37 -2 15 -2;

38 -1.8 18 -1.8; 39 -1.6 21 -1.6; 40 -1.4 24 -1.4; 41 1.2 30 1.2;

42 -1.2 30 1.2; 43 1.2 30 -1.2; 44 -1.2 30 -1.2; 45 4.2 27 1.2; 46 7.2 27 1.2;

47 4.2 30 1.2; 48 4.2 27 -1.2; 49 7.2 27 -1.2; 50 4.2 30 -1.2; 51 -4.2 27 1.2;

52 -7.2 27 1.2; 53 -4.2 30 1.2; 54 -4.2 27 -1.2; 55 -7.2 27 -1.2;

56 -4.2 30 -1.2; 57 1.2 33 1.2; 58 -1.2 33 1.2; 59 1.2 33 -1.2;

60 -1.2 33 -1.2; 61 0 35 0;

MEMBER INCIDENCES

1 1 3; 2 3 4; 3 4 5; 4 5 6; 5 6 7; 6 7 8; 7 8 9; 8 9 10; 9 10 2; 10 11 13;

11 13 14; 12 14 15; 13 15 16; 14 16 17; 15 17 18; 16 18 19; 17 19 20; 18 20 12;

19 13 3; 20 14 4; 21 15 5; 22 16 6; 23 17 7; 24 18 8; 25 19 9; 26 20 10;

27 12 2; 28 11 3; 29 1 13; 30 13 4; 31 3 14; 32 14 5; 33 15 4; 34 15 6;

35 16 5; 36 16 7; 37 17 6; 38 17 8; 39 18 7; 40 18 9; 41 19 8; 42 19 10;

43 20 9; 44 20 2; 45 12 10; 46 21 23; 47 23 24; 48 24 25; 49 25 26; 50 26 27;

51 27 28; 52 28 29; 53 29 30; 54 30 22; 55 3 23; 56 4 24; 57 5 25; 58 6 26;

59 7 27; 60 8 28; 61 9 29; 62 10 30; 63 2 22; 64 1 23; 65 21 3; 66 3 24;

67 23 4; 68 4 25; 69 5 24; 70 5 26; 71 6 25; 72 6 27; 73 7 26; 74 7 28;

75 8 27; 76 8 29; 77 9 28; 78 9 30; 79 10 29; 80 10 22; 81 2 30; 82 31 33;

83 33 34; 84 34 35; 85 35 36; 86 36 37; 87 37 38; 88 38 39; 89 39 40; 90 40 32;

91 23 33; 92 24 34; 93 25 35; 94 26 36; 95 27 37; 96 28 38; 97 29 39; 98 30 40;

99 22 32; 100 21 33; 101 31 23; 102 23 34; 103 33 24; 104 24 35; 105 25 34;

106 25 36; 107 26 35; 108 26 37; 109 27 36; 110 27 38; 111 28 37; 112 28 39;

113 29 38; 114 29 40; 115 30 39; 116 30 32; 117 22 40; 118 33 13; 119 34 14;

120 35 15; 121 36 16; 122 37 17; 123 38 18; 124 39 19; 125 40 20; 126 32 12;

127 31 13; 128 11 33; 129 33 14; 130 13 34; 131 34 15; 132 35 14; 133 35 16;

134 36 15; 135 36 17; 136 37 16; 137 37 18; 138 38 17; 139 38 19; 140 39 18;

141 39 20; 142 40 19; 143 40 12; 144 32 20; 145 32 44; 146 12 42; 147 2 41;

148 22 43; 149 42 41; 150 41 43; 151 43 44; 152 44 42; 153 12 41; 154 42 2;

155 22 41; 156 43 2; 157 43 32; 158 44 22; 159 12 44; 160 32 42; 161 41 47;

162 47 45; 163 45 2; 164 47 46; 165 46 45; 166 41 45; 167 43 50; 168 50 48;

169 48 22; 170 50 49; 171 49 48; 172 43 48; 173 47 50; 174 46 49; 175 45 48;

176 41 50; 177 50 46; 178 43 47; 179 47 49; 180 22 50; 181 2 47; 182 22 45;

183 2 48; 184 47 48; 185 50 45; 186 45 49; 187 48 46; 188 42 53; 189 53 51;

190 51 12; 191 53 52; 192 52 51; 193 42 51; 194 44 56; 195 56 54; 196 54 32;

197 56 55; 198 55 54; 199 44 54; 200 53 56; 201 52 55; 202 51 54; 203 42 56;

204 56 52; 205 44 53; 206 53 55; 207 32 56; 208 12 53; 209 32 51; 210 12 54;

211 53 54; 212 56 51; 213 51 55; 214 54 52; 215 44 60; 216 42 58; 217 41 57;

218 43 59; 219 60 59; 220 59 57; 221 57 58; 222 58 60; 223 44 58; 224 42 60;

225 42 57; 226 41 58; 227 44 59; 228 43 60; 229 43 57; 230 41 59; 231 60 57;

232 59 58; 235 33 3; 236 13 23; 237 34 4; 238 14 24; 239 35 5; 240 15 25;

241 36 6; 242 16 26; 243 37 7; 244 17 27; 245 38 8; 246 18 28; 247 39 9;

248 19 29; 249 40 10; 250 20 30; 251 32 2; 252 22 12; 253 44 41; 254 43 42;

Section 9C

9-87

255 60 61; 256 58 61; 257 57 61; 258 59 61;

MEMBER PROPERTY INDIAN

1 TO 18 46 TO 54 82 TO 90 145 TO 148 215 TO 218 TA LD ISA200X150X18 SP 0.01

19 TO 26 28 TO 45 55 TO 62 64 TO 81 91 TO 98 100 TO 125 127 TO 144 155 156 -

159 160 223 224 229 230 235 TO 250 TA ST ISA150X150X10

27 63 99 126 149 TO 154 157 158 161 TO 214 219 TO 222 225 TO 228 231 232 251 -

252 TO 258 TA ST ISA80X50X6

CONSTANTS

E 2.05e+008 ALL

POISSON 0.3 ALL

DENSITY 76.8195 ALL

ALPHA 6.5e-006 ALL

SUPPORTS

1 11 21 31 FIXED

UNIT METER KG

LOAD 1 VERT

SELFWEIGHT Y -1

JOINT LOAD

61 FX 732

46 49 52 55 FX 153

61 FX 1280 FY -1016 FZ 160

46 49 52 55 FX 9006 FY -7844 FZ 1968

2 12 22 32 FX 4503 FY -3937 FZ 1968

LOAD 2 GWBC

SELFWEIGHT Y -1

JOINT LOAD

61 FX 549

46 49 52 55 FX 1148

61 FX 515 FY -762 FZ 2342

46 49 52 55 FX 6755 FY -5906

2 12 22 32 FX 3378 FY -2953

LOAD 3 LEFT PCBC

SELFWEIGHT Y -1

JOINT LOAD

61 FX 549

46 49 52 55 FX 1148

61 FX 960 FY -762

46 49 FX 6755 FY -5906

52 55 FX 4211 FY -4551 FZ 13293

2 12 22 32 FX 3378 FY -2953

LOAD 4 RIGHT PCBC

SELFWEIGHT Y -1

JOINT LOAD

61 FX 549

46 49 52 55 FX 1148

61 FX 960 FY -762

52 55 FX 6755 FY -5906

46 49 FX 4211 FY -4551 FZ 13293

2 12 22 32 FX 3378 FY -2953

PERFORM ANALYSIS

UNIT NEW MMS

PARAMETER

CODE IS802


Section 9C

9-88

LY 2800 MEMB 28 LZ 2800 MEMB 28

MAIN 1.0 MEMB 1

ELA 4 MEMB 1

CNSF 1.0 MEMB 28

DBL 16 ALL

GUSSET 8 ALL

TRACK 9 ALL

CHECK CODE MEMB 1 28

FINISH

Output of design result

Section 9C

9-89

DETAILS OF CALCULATION ---------------------- CHECK FOR MINIMUM THICKNESS --------------------------- TYPE : PAINTED MIN. ALLOWABLE THICKNESS : 6.0 MM ACTUAL THICKNESS : 18.0 MM RESULT : PASS CHECK FOR SLENDERNESS RATIO --------------------------- VALUE OF L/r : 48.49 EQN. USED TO FIND KL/r : 60.0 + 0.5*L/r ACTUAL VALUE OF KL/r : 84.25 ALLOWABLE KL/r : 120.00 RESULT : PASS CALCULATION OF ALLOWABLE STRESS --------------------------------- CRITICAL CONDITION : COMPRESSION Cc : sqrt (2*3.141592*3.141592*E/fy) : 127.24 b : LENGTH OF LEG - WEB THICKNESS - ROOT RADIUS : 200.0 - 18.0 - 13.5 : 168.5 MM (b/t)lim : 210/sqrt(fy) : 13.28 (b/t)cal : 9.36 (b/t)cal <= (b/t)lim AND KL/r <= Cc ALLOWABLE AXIAL COMP. STRESS : (1- 0.5*(KL/r/Cc)*(KL/r/Cc))*fy :

195.15 MPA CHECK AGAINST PERMISSIBLE STRESS -------------------------------- LOAD NO. : 1 DESIGN AXIAL FORCE : 1742002.38 N ACTUAL AXIAL COMP. STRESS :1742002.38 / 11952.0 : 145.75 MPA RESULT : PASS


Section 9C

9-90

BOLTING ------- BOLT DIA : 16 MM SHEARING CAP : 87.66 KN BEARING CAP : 55.81 KN BOLT CAP : 55.81 KN NO. OF BOLTS REQD. : 32

Section 9C

9-91

DETAILS OF CALCULATION ---------------------- CHECK FOR MINIMUM THICKNESS --------------------------- TYPE : PAINTED MIN. ALLOWABLE THICKNESS : 6.0 MM ACTUAL THICKNESS : 10.0 MM RESULT : PASS CHECK FOR SLENDERNESS RATIO --------------------------- VALUE OF L/r : 95.56 EQN. USED TO FIND KL/r : K*L/r ACTUAL VALUE OF KL/r : 95.56 ALLOWABLE KL/r : 400.00 RESULT : PASS CALCULATION OF ALLOWABLE STRESS --------------------------------- CRITICAL CONDITION : TENSION ALLOWABLE AXIAL TENSILE STRESS : 249.94 MPA CHECK AGAINST PERMISSIBLE STRESS -------------------------------- LOAD NO. : 3 DESIGN AXIAL FORCE : 112909.27 N ACTUAL AXIAL TENSILE STRESS : 112909.27 / ( 2903.0*0.801 ) : 48.53 MPA RESULT : PASS BOLTING ------- BOLT DIA : 16 MM SHEARING CAP : 43.83 KN BEARING CAP : 55.81 KN BOLT CAP : 43.83 KN NO. OF BOLTS REQD. : 3 ********** END OF TABULATED RESULT OF DESIGN ***********


Section 9C

9-92

9-93

Design Per Indian Cold Formed

Steel Code

9D.1 General

Provisions of IS:801-1975, including revisions dated May, 1988,

have been implemented. The program allows design of single

(non-composite) members in tension, compression, bending, shear,

as well as their combinations. Cold work of forming strengthening

effects has been included as an option.

9D.2 Cross-Sectional Properties



Property Tables from IS:811-1987 (Specification for cold formed

light gauge structural steel sections).


Channel with Lips


Angle without Lips

Z with Lips

Hat

Shape selection may be done using the member property pages of

the graphical user interface (GUI) or by specifying the section


Section 9D

Design Per Indian Cold Formed Steel Code

Section 9D

9-94





9D.3 Design Procedure


1. Code Checking


load effects, in accordance with IS:801-1975. Code checking is






parameter.

2. Member Selection


shapes database (IS standard sections) for alternative members that

pass the code check and meet the least weight criterion. In




angle, etc.) and, if a suitable replacement is found, presents design






with Clause 5.2.1.1. Cross-sectional properties and overall

slenderness of members are checked for compliance with

Section 9D

9-95

Clause 6.6.3, Maximum Effective Slenderness Ratio for


Clause 5.2.3, Maximum Flat Width Ratios for Elements in

Compression

Clause 5.2.4, Maximum Section Depths.

The program will check member strength in accordance with

Clause 6 of the Standard as follows:

Members in tension

Resistance is calculated in accordance with Clauses 6.1

Members in bending and shear


a) 6.4.1 Shear stress in webs,

b) 6.4.2 Bending stress in webs

c) 6.4.3 Combined Bending and Shear in Webs.

Members in compression


a) 6.2 Compression on flat unstiffened element,

b) 6.6.1.1 Shapes not subject to torsional-flexural buckling,

c) 6.6.1.2 Singly-symmetric sections and nonsymmetrical

shapes of open cross section or intermittently fastened

singly-symmetrical components of built-up shapes having

Q = 1.0 which may be subject to torsional-flexural

buckling,


Section 9D

9-96

d) 6.6.1.3 Singly-symmetric sections and nonsymmetrical

shapes or intermittently fastened singly-symmetrical

components of built-up shapes having Q < 1.0 which may

be subject to torsional-flexural buckling,

e) 6.8 Cylindrical Tubular Sections.

Members in compression and bending


a) All clauses for members in compression

&

b) 6.3 Laterally Unsupported Members,

c) 6.7.1 Doubly-symmetric shapes or Shapes not subjected

to torsional or torsional-flexural buckling

d) 6.7.2. Singly-symmetric shapes or Intermittently fastened

singly-symmetric components of built-up shapes having

Q=1.0 which may be subjected to torsional-flexural

buckling

e) 6.7.3. Singly-symmetric shapes or Intermittently fastened

singly-symmetric components of built-up shapes having

Q<1.0 which may be subjected to torsional-flexural

buckling.

Input for the coefficients of uniform bending must be provided by

the user.

Section 9D

9-97

The following table contains the input parameters for specifying

values of design variables and selection of design options. Note:

Once a parameter is specified, its value stays at that specified

number till it is specified again. This is the way STAAD works

for all codes.

COLD FORMED STEEL DESIGN PARAMETERS

Parameter

Name

Default

Value Description

BEAM 1.0 When this parameter is set to 1.0 (default), the adequacy of the member is determined by checking a total of 13 equally spaced locations along the length of the member. If the BEAM value is 0.0, the 13 location check is not conducted, and instead, checking is done only at the locations specified by the SECTION command (See STAAD manual for details. For TRUSS members only start and end locations are designed.

CMZ 1.0 Coefficient of equivalent uniform bending z. See IS:801-1975, 6.7. Used for Combined axial load and bending design. Values range from 0.4 to 1.0.

CMY 0.85 Coefficient of equivalent uniform bending y. See IS:801-1975, 6.7. Used for Combined axial load and bending design. Values range from 0.4 to 1.0.

CWY 0.85 Specifies whether the cold work of forming strengthening effect should be included in resistance computation. See IS:801-1975, 6.1.1



FLX 1 Specifies whether torsional-flexural buckling restraint is provided or is not necessary for the member. See IS:801-1975, 6.6.1

Values:

0 – Section not subject to torsional flexural buckling 1 – Section subject to torsional flexural buckling


Section 9D

9-98


Parameter

Name

Default

Value Description

FU 450 MPa (4588.72 kg/cm2)

Ultimate tensile strength of steel in current units.

FYLD 353.04 MPa

(3600.0 kg/cm2)

Yield strength of steel in current units.

KX 1.0 Effective length factor for torsional buckling. It is a fraction and is unit-less. Values can range from 0.01 (for a column completely prevented from buckling) to any user specified large value. It is used to compute the KL/R ratio for twisting for determining the capacity in axial compression.

KY 1.0 Effective length factor for overall buckling about the local Y-axis. It is a fraction and is unit-less. Values can range from 0.01 (for a column completely prevented from buckling) to any user specified large value. It is used to compute the KL/R ratio for determining the capacity in axial compression.

KZ 1.0 Effective length factor for overall buckling in the local Z-axis. It is a fraction and is unit-less. Values can range from 0.01 (for a member completely prevented from buckling) to any user specified large value. It is used to compute the KL/R ratio for determining the capacity in axial compression.

LX Member length

Unbraced length for twisting. It is input in the current units of length. Values can range from 0.01 (for a member completely prevented from torsional buckling) to any user specified large value. It is used to compute the KL/R ratio for twisting for determining the capacity in axial compression.

LY Member length

Effective length for overall buckling in the local Y-axis. It is input in the current units of length. Values can range from 0.01 (for a member completely prevented from buckling) to any user specified large value. It is used to compute the KL/R ratio for determining the capacity in axial compression.

Section 9D

9-99


Parameter

Name

Default

Value Description

LZ Member length

Effective length for overall buckling in the local Z-axis. It is input in the current units of length. Values can range from 0.01 (for a member completely prevented from buckling) to any user specified large value. It is used to compute the KL/R ratio for determining the capacity in axial compression.

MAIN 0 0 – Check slenderness ratio

0 – Do not check slenderness ratio

NSF 1.0 Net section factor for tension members DMAX

2540.0 cm. Maximum allowable depth. It is input in the current units of

length.


TRACK 0 This parameter is used to control the level of detail in which the design output is reported in the output file. The allowable values are: 0 - Prints only the member number, section name, ratio, and

PASS/FAIL status. 1 - Prints the design summary in addition to that printed by

TRACK 1 2 - Prints member and material properties in addition to that

printed by TRACK 2. TSA 1 Specifies whether webs of flexural members are adequately

stiffened to satisfy the requirements of IS:801-1975, 5.2.4.

Values:

0 – Do not comply with 5.2.4

1 – Comply with 5.2.4


Section 9D

9-100

Section 10

Japanese Codes

;alksdf;lkajf

10-1

Concrete Design Per AIJ



on the AIJ standard for structural calculation of Reinforced

Concrete Structures (1985 edition). Design for a member involves

calculation of the amount of reinforcement required for the

member. Calculations are based on the user specified properties

and the member forces obtained from the analysis. In addition, the

details regarding placement of the reinforcement on the cross

section are also reported in the output.



designed.

For Beams Prismatic (Rectangular & Square)






input:

Section 10A


Section 10A

10-2

UNIT MM

MEMBER PROPERTY

1 3 TO 7 9 PRISM YD 450. ZD 250.

11 13 PR YD 350.




with 350mm diameter. It is absolutely imperative that the user not




compression members. Slenderness effects result in additional

forces being exerted on the column over and above those obtained

from the elastic analysis. There are two options by which the

slenderness effects can be accommodated.

The first option is to compute the secondary moments through an

exact analysis. Secondary moments are caused by the interaction

of the axial loads and the relative end displacements of a member.

The axial loads and joint displacements are first determined from

an elastic stiffness analysis and the secondary moments are then

evaluated.

The second option is to approximately magnify the moments from

the elastic analysis and design the column for the magnified

moment. It is assumed that the magnified moment is equivalent to

the total moment comprised of the sum of primary and secondary

moments.

STAAD provides facilities to design according to both of the

above methods. To utilize the first method, the command PDELTA

ANALYSIS must be used instead of PERFORM ANALYSIS in the

Section 10A

10-3

input file. The user must note that to take advantage of this








automatically. The second method mentioned above is utilized by

providing the magnification factor as a concrete design parameter

(See the parameter MMAG in Table 9A.1). The column is designed

for the axial load and total of primary and secondary biaxial

moments if the first method is used and for the axial load and

magnified biaxial moments if the second method is used.

10A.5 Beam Design

Beams are designed for flexure, shear and torsion. Program

considers 12 equally spaced sections of the beam member.

However this number can be redefined by NSECTION parameter.

All these sections are designed for flexure, shear and torsion for

all the load cases and print out the design results for most critical

load case.

Design for Flexure

Reinforcement for positive and negative moments are calculated

on the basis of section properties provided by the user. Program

first try to design the section for =0 and pt = balanced

reinforcement ratio. If allowable moment is lower than the actual

moment program increases value for same pt and checks the

satisfactory conditions. If conditions are not satisfied this

procedure continues until reaches to 1.0 and then pt value is

increased keeping = 1.0. This procedure continues until pt

reaches to its maximum value( 2 % ). But if the allowable moment

for pt = maximum value and = 1.0 is lower than the actual

moment the program gives message that the section fa ils.

This program automatically calculates the Bar size and no. of bars

needed to design the section. It arranges the bar in layers as per


Section 10A

10-4

the requirements and recalculate the effective depth and redesign

the sections for this effective depth.

Notes:

Beams are designed for MZ only. The moment MY is not

considered in flexure design

MMAG parameter can be used to increase design moment

1.4 cm. is added to the clear cover to take stirrup size into

consideration for flexure design.

STAAD beam design procedure is based on the local practice

and considering the fact that Japan is a high seismic zone area.

Design for Shear

Shear design of beam is done for Qy value. The update effective

depth is used for allowable shear stress calculation. Allowable

shear stress of concrete is automatically calculated from design

load type (permanent or temporary) and given density of concrete.

Program calculates required Bar size and spacing of stirrups. Pw is

calculated for design Bar size and spacing and all the necessary

checking is done.

For seismic load it is needed to increase shear force 1.5 times the

actual value and this can be done utilizing SMAG parameter.

Notes:

SMAG parameter can be used if its needed to increase the

Design Shear Force without changing Design Moment.

Stirrups are always assumed to be 2-legged

Governing density to determine Light weight or Normal

Weight Concrete is 2.3 kg/sq. cm

Section 10A

10-5


UNIT KG CM


CODE JAPAN

FYMAIN SRR295 ALL

FYSEC SRR295 ALL

FC 350 ALL

CLEAR 2.5 MEM 2 TO 6


DESIGN BEAM 2 TO 9

END CONCRETE DESIGN

Design for Torsion

Torsion design for beam is optional. If TORSION parameter value

is 1.0, program design that beam for torsion. Program first checks

whether extra reinforcement is needed for torsion or not. If

additional reinforcement is needed, this additional pt is added to

flexure pt and additional Pw is added to shear design Pw.

10A.6 Column Design

Columns are designed for axial force, MZ moment, MY moment

and shear force. Both the ends of the members are designed for all

the load cases and the loading which produces largest amount of

reinforcement is called as critical load. If Track 0 or Track 1 is

used, design results will be printed for critical load only. But if

Track 2 is used user can get details design results of that member.

Pt needed for minimum axial force, maximum axial force,

maximum MZ, maximum MY among all the load cases for both the

ends will be printed. If MMAG parameter is used, the column

moments will be multiplied by that value. If SMAG parameter is

used, column shear force will be multiplied by that value.

Column design is done for Rectangular, Square and Circular

sections. For rectangular and square sections Pt value is calculated


Section 10A

10-6

separately for MZ and MY, while for circular sections Pg value is

calculated for MZ and MY separately.

Column design for biaxial moments is optional. If BIAXIAL

parameter value 1.0, program will design the column for biaxial

moments. Otherwise column design is always uniaxial type.

Steps involved :

1) Depending on the axial force zone is determined for Pt = 0.0 .

2) If the column is in "zone A", design is performed by

increasing Pt and checking allowable load for that known Pt

and known actual eccentricity of the column.

3) If the column is in "zone B" or in "zone C", xn is calculated

for given P and Pt and checking is done for allowable moment,

if allowable moment is less than the actual moment, program

increases Pt and this procedure continues until the column

design conditions are satisfied or the column fails as the

required Pt is higher than Pt maximum value.

4) If the column is in tension, design is done by considering

allowable tensile stress of steel only.

5) If biaxial design is requested program solve the following

interaction equation

0.1Mzcap

Mz

Mycap

My

where, = 1.0+1.66666666 (ratio-0.2), ratio = P/Pcap &

1.0 2.0, Mycap, Mzcap & Pcap represents section

capacity

6) If the interaction equation is not satisfied program increases Pt

and calculates Pcap, Mycap and Mzcap and solve the

interaction equation again and this process continues until the

Section 10A

10-7

eqn. is satisfied or the column fails as Pt exceeds its maximum

limit.

7) If biaxial design is not requested program assumes that

interaction equation is satisfied ( if uniaxial design is

performed successfully ).

8) If the interaction equation is satisfied program determines bar

size and calculates no. of bars and details output is written.


UNIT KGS CMS


CODE JAPAN

FYMAIN SRR295 ALL

FC 210 ALL

CLEAR 2.5 MEMB 2 TO 6


END CONCRETE DESIGN


To design a slab or a wall, it must first be modelled using finite

elements and analysed. The command specifications are in

accordance with Chapter 2 and Chapter 6 of the Technical

Reference Manual.




to resist the Mx moment is denoted as longitudinal reinforcement

and the reinforcement required to resist the My moment is denoted

as transverse reinforcement.


Section 10A

10-8

The longitudinal bar is the layer closest to the exterior face of the

slab or wall. The following parameters are those applicable to slab

and wall design:

1. FYMAIN Yield stress for reinforcing steel - transverse and

longitudinal.

2. FC Concrete grade

3. CLEAR Distance from the outer surface of the element to

the edge of the bar. This is considered the same on

both top and bottom surfaces of the element.

4. MINMAIN Minimum required size of longitudinal/transverse

reinforcing bar

The other parameters shown in Table 9A.1 are not applicable to

slab or wall design.

LONG.

TRANS.

X

Y

Z

M

MM

Mx

y

x

y






design being performed. Table 9A.1 contains a complete list of the

available parameters and their default values. It is necessary to

declare length and force units as centimeters and Kilograms before

performing the concrete design. Note: Once a parameter is



Section 10A

10-9

Table 10A.1 Japanese Concrete Design Parameters

Parameter

Name


FYMAIN SR235 Steel grade. Acceptable values for steel grade and their associated yield stress values are shown in the next table. Program automatically calculates yield stress value depending on design load type (permanent or temporary).

FYSEC SR235 Same as FYMAIN except this is for secondary steel.

FC 210 Kg/cm2 Compressive Strength of Concrete.

CL 3.0 cm Clear cover for Beam.

CLS 4.0 cm Clear side cover for Column.



MAXMAIN 41.0 cm Maximum main reinforcement bar size

MAXSEC 41.0 cm Maximum secondary reinforcement bar size.

SFACE 0.0 Face of support location at start of beam.

EFACE 0.0 Face of support location at end of beam. (Note: Both SFACE & EFACE are input as positive numbers).

REINF 0.0 Tied Column. A value of 1.0 will mean spiral.

MMAG 1.0 Design moment magnification factor

SMAG 1.0 Design shear magnification factor

LONG 0.0 Value to define design load type 0 = Permanent Loading 1 = Temporary Loading

BIAXIAL 0.0 Value to define biaxial or uniaxial design type for Column 0 = uniaxial design only 1 = design for biaxial moments

TORSION 0.0 Value to request for torsion design for beam 0 = torsion design not needed 1 = torsion design needed


Section 10A

10-10

Table 10A.1 Japanese Concrete Design Parameters

Parameter

Name


WIDTH ZD Width of concrete member. This value defaults to ZD as provided under MEMBER PROPERTIES.

DEPTH YD Depth of concrete member. This value defaults to YD as provided under MEMBER PROPERTIES.



0.0 = Critical section design results. 1.0 = Five section design results & design

forces. 2.0 = 12 section design results & design forces. COLUMN DESIGN:

1.0 = Detail design results for critical load case only.

2.0 = Design results for minimum P, maximum P, maximum MZ and maximum MY among all load cases for both ends.

Table of permissible Steel Grades and associated Yield Stresses

for FYMAIN and FYSEC parameters. (Default values in Kg/Cm^2)

Steel Grade Design Load Type Design Load Type

Long Term Short Term

SR235

SRR235

SDR235

22.76

34.14

SR295

SRR295

22.76 42.67

SD295A

SD295B

SDR295

28.45

42.67

SDR345

SD345

31.29 49.78

SD390 31.29 56.89

10-11

Steel Design Per AIJ

10B.1 General


implementation of the “Architectural Institute of Japan” (AIJ)

specifications for structural steel design (1986 edition) in STAAD.

The design philosophy and procedural logistics are based on the

principles of elastic analysis and allowable stress design. Facilities

are available for member selection as well as code checking. Two

major failure modes are recognized: failure by overstressing an d

failure by stability considerations. The following sections describe

the salient features of the design approach.


exceedance of the allowable stresses or capacities and the most

economical section is selected on the basis of the least weight


slenderness requirements and the stability criteria. Users are

recommended to adopt the following steps in performing the steel

design:

Specify the geometry and loads and perform the analysis.

Specify the design parameter values if different from the

default values.


selection.

Section 10B


Section 10B

10-12





complete flexibility in providing loading specifications and in

using appropriate load factors to create necessary loading

situations. Depending upon the analysis requirements, regular

stiffness analysis or P-Delta analysis may be specified. Dynamic

analysis may also be performed and the results combined with

static analysis results.


For specification of member properties of standard Japanese steel

shapes, the steel section library available in STAAD may be used.

The next section describes the syntax of commands used to assign

properties from the built-in steel table. Members properties may

also be specified using the User Table facility. For more

information on these facilities, refer to the STAAD Technical

Reference Manual.

10B.4 Built-in Japanese Steel Section Library



These properties are stored in a database file. If called for, these



for these members during the analysis. An example of member


section.

Section 10B

10-13


section library may be obtained using the tools of the graphical

user interface.


I shapes

I shapes are specified in the following way:

Note : While specifying the web thickness, the portion after the

decimal point should be excluded.

Example: 1 TO 9 TA ST I300X150X11

12 TO 15 TA ST I350X150X9

H shapes

H shapes are specified as follows:

Note: While specifying the web thickness, the portion after the decimal

point should be excluded.

Example: 1 TO 8 TA ST H200X100X4

13 TO 17 TA ST H350X350X12

I 250 X 125 X 10

Web thickness (mm)

Nominal width of flange (mm)

Section-type (I)

Nominal height (mm)

H 600 X 200 X 11

Web thickness (mm)


Section-type (H)

Nominal height (mm)


Section 10B

10-14

T shapes

T shapes are specified as follows:

Note : While specifying the web thickness, the portion after the

decimal point should be excluded

Example: 20 TO 25 TA ST T250X19

Channels

Channel sections are specified as follows.

Example: 25 TO 34 TA ST C125X65X6

46 TO 49 TA ST C200X90X8

Double Channels

Back to back double channels, with or without a spacing in

between them, are available. The letter D in front of the section

name is used to specify a double channel.

17 TO 27 TA D C300X90X10

45 TO 76 TA D C250X90X11 SP 2.0

In the above commands, members 17 to 27 are a back to back

double channel C300X90X10 with no spacing in between.

T 250 X 16

Flange thickness (mm)

Section-type (T)


C 300 X 90 X 10

Web thickness (mm)


Section-type (C)

Nominal height (mm)

Section 10B

10-15

Members 45 to 76 are a double channel C250X90X11 with a

spacing of 2 length units.

Angles


standard angle specification is as follows.

The letter L (signifying that the section is an angle) is followed by

the length of the legs and then the thickness of the leg, all in

millimetres. The word ST signifies that the section is a STandard

angle meaning that the major principal axis coincides with the

local YY axis specified in Chapter 1 of Section 1.5.2 of the User's

Manual.

Example: 1 4 TA ST L150X90X9

If the minor principal axis coincides with the local YY axis

specified in Chapter 2 of the User's Manual, the word RA (Reverse

Angle) should be used instead of ST as shown below.

7 TO 23 TA RA L90X75X9

Double angles

Short leg back to back and long leg back to back double angles

may be specified by using the words SD or LD in front of the

angle size. In the case of an equal angle, either SD or LD will

serve the purpose. The spacing between the angles may be

specified by using the word SP after the angle size followed by the

value of the spacing.

L 125 X 90 X 10

Thickness (mm)

Length of shorter side (mm)

Section-type (L)

Length of longer side (mm)


Section 10B

10-16

8 TO 25 TA SD L100X65X7 SP 2.0

36 TO 45 TA LD L300X90X11 SP 3.0

The first example indicates a short legs back to back double angle

comprised of 100X65X7 angles separated by 2 length units. The

latter is a long legs back to back double angle comprised of

300X90X11 angles separated by 3 length units.

Tubes

Tube names are input by their dimensions. For example,


is a tube that has a height of 8 length units, width of 6 length units

and a wall thickness of 0.5 length units. Only code checking, no

member selection can be performed on TUBE sections.

Pipes (Circular Hollow sections)

Circular hollow sections may be provided by specifying the word

PIPE followed by the outside and inside diameters of the section.

For example,


specifies a pipe with outside diameter of 25 length units and an

inside diameter of 20 length units. Only code checking, no member

selection, can be performed on PIPE sections.

Section 10B

10-17

Sample Input file containing Japanese shapes

STAAD SPACE

UNIT KIP FEET

JOINT COORD

1 0 0 0 12 11 0 0

MEMB INCIDENCE

1 1 2 11

UNIT INCH

MEMBER PROPERTY JAPANESE

* H-SHAPE

1 TA ST H200X100X4

* I SHAPE

2 TA ST I250X125X10

* T SHAPE

3 TA ST T200X19

* CHANNEL

4 TA ST C125X65X6

* DOUBLE CHANNEL

5 TA D C200X90X8

* REGULAR ANGLE

6 TA ST L100X75X7

* REVERSE ANGLE

7 TA RA L90X75X9

* DOUBLE ANGLE - LONG LEG BACK TO BACK

8 TA LD L125X75X7 SP 2.0

* DOUBLE ANGLE - SHORT LEG BACK TO BACK

9 TA SD L300X90X11 SP 1.5

* TUBE


* PIPE



FINISH


Section 10B

10-18


As mentioned before, member design and code checking in

STAAD are based upon the allowable stress design method. It is a



appropriate material under service conditions. The basic measure

of member capacities are the allowable stresses on the member

under various conditions of applied loading such as allowable

tensile stress, allowable compressive stress etc. These depend on

several factors such as cross sectional properties, slenderness

factors, unsupported width to thickness ratios and so on. Explained

here is the procedure adopted in STAAD for calculating such

capacities.

Design Capabilities

All types of available shapes like H-Shape, I-Shape, L-Shapes,

CHANNEL, PIPE, TUBE, Prismatic section etc. can be used as

member property and STAAD will automatically adopt the design

procedure for that particular shape if Steel Design is requested.

STEEL TABLE available within STAAD or UPTABLE facility can

be used for member property.

Methodology

For steel design, STAAD compares the actual stresses with the

allowable stresses as required by AIJ specifications. The design

procedure consist of following three steps.

1) Calculation of sectional properties

Program extract sectional properties like sectional area ( A ),

Moment of Inertia about Y axis and Z axis ( Iyy, Izz) from in-

built Japanese Steel Table and calculates Zz, Zy, iy, iz using

appropriate formula. For calculation of i ( radius of gyration

needed for bending ), program calculates moment of inertia ( Ii

)and sectional area ( Ai ) for 1/6th section and then uses

following formula:

Section 10B

10-19

Ai

Iii

Please note, that the above mentioned procedure for

calculation of i is applicable for I shape, H shape and Channel

sections.

2) Calculation of actual and allowable stresses

Program calculates actual and allowable stresses by following

methods:

i) Axial Stress:

Actual tensile stresses ( FT ) = Force / ( A NSF ),

NSF = Net Section Factor for tension

Actual compressive stress ( FC ) = Force / A

Allowable tensile stress ( ft ) = F / 1.5 (For Permanent

Case)

= F ( For Temporary Case )

Allowable compressive stress

when /F x / x4.1 )fc( 2

when / /F x 77.2 2

= fc 1.5 (For Temporary Case )

where, )xF6/(.E2 =F) , =3 / 2 + 2 / 3 ( / )2

ii) Bending Stress:

Actual bending stress for My for compression

( Fbcy) = My / Zcy

Actual bending stress for Mz for compression

( Fbcz) = Mz / Zcz

Actual bending stress for My for tension

( Fbty ) = My / Zcy Or ( Fbty ) = My / Zty

Actual bending stress for Mz for tension

( Fbtz ) = Mz / Zcz Or (Fbtz ) = Mz / Ztz


Section 10B

10-20

where, Zcy , Zcz are section modulus for compression and

Zty, Ztz are section modulus for tension

Allowable bending stress for My

(fbcy) = ft

Allowable bending stress for Mz

(fbcz) = { 1-.4 (lb / i )2 / (C 2)}ft max

= 900/ ( lb h / Af )

For Temporary case, fbcz = 1.5 (fbcz for Permanent

Case)

where, C = 1.75 -1.05(M2/M1)+0.3(M2/M1)2

Allowable bending stress for My ( fbty) = ft

Allowable bending stress for Mz ( fbtz) = fbcz

iii) Shear Stress

Actual shear stresses are calculated by following formula :

qy = Qy / Aww,

Where, Aww = web shear area = product of depth and web

thickness

qz = Qz / Aff ,

Where, Aff = flange shear area = 2/3 times total flange

areas

Allowable shear stress ( fs ) = Fs / 1.5 , Fs = F / 3

3) Checking design requirements:

User provided RATIO value (default 1.0) is used for checking

design requirements

The following conditions are checked to meet the AIJ

specifications. For all the conditions calculated value should not

be more than the value of RATIO. If for any condition value

exceeds RATIO , program gives the message that the section fails.

Conditions:

i) Axial tensile stress ratio = FT / ft

ii) Axial compressive stress ratio = FC / fc

iii) Combined compression &

bending ratio = FC/fc+Fbcz/fbcz+Fbcy/fbcy

Section 10B

10-21

iv) Combined compression &

bending ratio = (Fbtz+Fbty-FC) / ft

v) Combined tension & bending ratio = (FT+Fbtz+Fbty) / ft

vi) Combined tension & bending ratio = Fbcz/fbcz+Fbcy/fbcy-

FT/ft

vii) Shear stress ratio for qy = qy / fs

viii) Shear stress ratio for qz = qz / fs

New Output Format ( TRACK -- 3 )

One new output format has been introduced which provides details

step by step information of Steel Design for guiding load case

only. If Section command is used before Parameter command this

output will provide details information for all the sections

specified by Section Command.

Please note, that this output format is available only when Beam

parameter value is 0 and Track parameter value is 3. If section

command is not used design information will be printed for two

ends only. If Member Truss option is used no Shear Design

information will be printed.

Example:

SECTION 0.0 0.25 0.5 0.75 1.0 ALL

PARAMETER

CODE JAPAN

BEAM 0.0 ALL

TMP 0.0 MEMB 1 to 4

TMP 1.0 MEMB 5 to 8

TRACK 3 ALL

CHECK CODE ALL

FINISH


Allowable axial stress in tension is calculated per section 5.1 (1)

of the AIJ code. In members with axial tension, the tensile load

must not exceed the tension capacity of the member. The tension


Section 10B

10-22

capacity of the member is calculated on the basis of the member

area. STAAD calculates the tension capacity of a given member

based on a user supplied net section factor (NSF-a default value of

1.0 is present but may be altered by changing the input value, see

Table 8B.1) and proceeds with member selection or code checking.



according to the procedure of section 5.1 (3). Compressive

resistance is a function of the slenderness of the cross -section

(Kl/r ratio) and the user may control the slenderness value by

modifying parameters such as KY, LY, KZ and LZ. In the absence

of user provided values for effective length, the actual member

length will be used. The slenderness ratios are checked against the

permissible values specified in Chapter 11 of the AIJ code.

Allowable stress for Bending

The permissible bending compressive and tensile stresses are

dependent on such factors as length of outstanding legs, thickness

of flanges, unsupported length of the compression flange (UNL,

defaults to member length) etc. The allowable stresses in bending

(compressive and tensile) are calculated as per the criteria of

Clause 5.1 (4) of the code.

Allowable stress for Shear

Shear capacities are a function of web depth, web thickness etc.

The allowable stresses in shear are computed according to Clause

5.1 (2) of the code.




locations of the member for all modelled loading situations.

Members subjected to axial tension and bending are checked using

the criteria of clause 6.2. For members with axial compression and

bending, the criteria of clause 6.1 is used.

Section 10B

10-23





engineer to the program. The default parameter values have been


conventional design. Depending on the particular design

requirements of the situation, some or all of these parameter

values may have to be changed to exactly model the physical

structure. Note: Once a parameter is specified, its value stays at



Table 10B.1 - Japanese Steel Design Parameters

Parameter

Name


KY 1.0 K value in local y-axis. Usually, this is the minor axis.

KZ 1.0 K value in local z-axis. Usually, this is the major axis.

LY Member Length

Length in local y-axis to calculate slenderness ratio.

LZ Member Length

Same as above except in z-axis

FYLD 235 MPA Yield strength of steel in Megapascal.


UNL Member Length

Unsupported length for calculating allowable bending stress.

UNF 1.0 Same as above provided as a fraction of actual member length.



Section 10B

10-24

Table 10B.1 - Japanese Steel Design Parameters

Parameter

Name



MAIN 0.0 0.0 = check for slenderness 1.0 = suppress slenderness check

TRACK 0.0 0.0 = Suppress critical member stresses 1.0 = Print all critical member stresses 2.0 = Print expanded output

DMAX 100 cm Maximum allowable depth for member.

DMIN 0.0 cm Minimum allowable depth for member.

TMP 0 (Permanent

Load)

0 = Permanent Loading 1 = Temporary Loading


BEAM 0.0 0.0 = design only for end moments or those at locations specified by the SECTION command.

1.0 = calculate moments at twelfth points along the beam, and use the maximum Mz location for design.

DFF None (Mandatory for

deflection check)






NOTE:





"Deflection Length" may be different. For example, refer to



Section 10B

10-25







D = Maximum local deflection for members1, 2 and 3.

D

1

2 3

4

1

2 3


DFF 300. ALL

DJ1 1 ALL

DJ2 4 ALL

2) If DJ1 and DJ2 are not used, "Deflection Length" wil l default





10B.8 Code Checking



transmitted to it by the loads on the structure. The adequacy is

checked per the AIJ requirements.






zero (default), design will be based on the forces at the start and

end joints of the member. The code checking output labels the


governing load case, location (distance from start joint) and



Section 10B

10-26




based on the forces and moments obtained from the most recent

analysis. The section selected will be of the same type as that

specified initially. For example, a member specified initially as a

channel will have a channel selected for it. Selection of members

whose properties are originally provided from a user table will be

limited to sections in the user table. Member selection cannot be

performed on TUBES, PIPES or members listed as PRISMATIC.


UNIT METER

PARAMETER

CODE JAPAN

NSF 0.85 ALL

UNL 10.0 MEMBER 7

KY 1.2 MEMBER 3 4

RATIO 0.9 ALL

TRACK 1.0 ALL

CHECK CODE ALL

SELECT ALL

Section 11

Mexican Codes

11-1

Concrete Design Per MEX NTC 1987


STAAD has the capabilities for per forming concrete design. It will

calculate the reinforcement needed for the specified concrete

section. All the concrete design calculations are based on the

current: Complementary Technical Standards for the Design and

Construction of Concrete Structures – Nov. 1987. (Normas

Técnicas Complementarias para Diseño y construcción de

Estructuras de Concreto) of the Mexican Construction Code for the

Federal District –Aug. 1993 (Reglamento de Construcciones para

el Distrito Federal).


The following types of cross sections can be defined for concrete

design.


For Beams Prismatic (Rectangular & Square), Trapezoidal

and T-shapes

For Slabs Finite element with a specified thickness

Section 11A

Concrete Design Per Mexican Code

Section 11A

11-2





input:

UNIT CM

MEMBER PROPERTY

13 TO 79 PRISM YD 40. ZD 20. IZ 53333 IY 13333

11 13 PR YD 20.

14 TO 16 PRIS YD 24. ZD 48. YB 18. ZB 12.

17 TO 19 PR YD 24. ZD 18. ZB 12.

In the above input, the first set of members are rectangular (40 cm

depth and 20 cm width) and the second set of members, with only

depth and no width provided, will be assumed to be circular with 20

cm diameter. Note that no area (AX) is provided for these members.

For concrete design, this property must not be provided. If shear areas

and moments of inertias are not provided, the program calculates

these values from YD and ZD. Notice that in the above example the

IZ and IY values provided are actually 50% of the values calculated

using YD and ZD. This is a conventional practice which takes int o

consideration revised section parameters due to cracking of section.

Section 11A

11-3

Note that the third and the fourth set of members in the above

example represent a T-shape and a TRAPEZOIDAL shape

respectively. Depending on the properties (YD, ZD, YB, ZB, etc.)

provided, the program will determine whether the section is

rectangular, trapezoidal or T-shaped and the BEAM design will be

done accordingly.



perform design by the Mexican code. Default parameter values



suit the particular design being performed. Table 3.1 is a complete

list of the available parameters and their default values.

The manual describes the commands required to provide these

parameters in the input file. For example, the values of SFACE

and EFACE (parameters that are used in shear design), the

distances of the face of supports from the end nodes of a beam, are

assigned values of zero by default but may be changed depending

on the actual situation. Similarly, beams and columns are designed

for moments directly obtained from the analyses without any

magnification. The factors MMAGx and MMAGy may be used for

magnification of column moments. For beams, the user may

generate load cases which contain loads magnified by the

appropriate load factors. Note: Once a parameter is specified, its




Section 11A

11-4

Table 11A.1 – Mexican Concrete Design Parameters


Name Value

FYMAIN 4200Kg/cm2 Yield Stress for main reinforcing steel

FYSTIRR 4200Kg/cm2 Yield Stress for stirrup reinforcing steel

FC 200Kg/cm2 Compressive Strength of Concrete

clear_cover_top 3cm Clear cover for top reinforcement

clear_cover_bottom 3cm Clear cover for bottom reinforcement

clear_cover_side 3cm Clear cover for side reinforcement

MINMAIN** No 2.5 bar Minimum main reinforcement bar size (Number 2 -18)

MINSEC** No 2.5 bar Minimum secondary reinforcement bar size (Number 2 -18)

MAXMAIN** No 12 bar Maximum main reinforcement bar size (Number 2 -18)

SFACE 0

Face to support location of start of beam. If specified, for shear force at start is computed at a distance of SFACE+d from the start joint of the member. Positive number

EFACE 0

Face to support location of end of beam. If specified, for shear force at start is computed at a distance of

EFACE+d from the start joint of the member. Positive number.

REINF 0 Tied Column. A value of 1 will mean spiral.

AMAGx

AMAGy 1

A factor by which the column design moments will be

magnified

WIDTH *ZD Width of concrete member. This value defaults to ZD

as provided under MEMBER PROPERTIES

DEPTH *YD Depth of concrete member. This value defaults to YD

as provided under MEMBER PROPERTIES

NSECTION 12 Number of equally-spaced sections to be considered in

finding critical moments for beam design

Section 11A

11-5



Name Value

TRACK 0

Beam Design

0 = Critical Moment will not be printed out with

beam design report.

1 = will mean a print out.

2 = will print out required steel areas for all intermediate sections specified by NSECTION.

Column Design

0 = will print out detailed design results.

1 = will mean a print out column interation analysis results in addition to TRACK 0 output.

2 = will print out a schematic interaction diagram and intermediate interaction values in addition to all of the above.

BARTYPE 2 0: IMPERIAL (No 3 to 18) 1: METRIC (4.2 to 60mm)

2: MEXICAN (No 2 to 18)

DIM_PRECAUTION TRUE TRUE: Precautions are taken to assure dimensions FALSE: Not precautions taken - Section reduction to

section 1.5 NTC Concrete

EXPOSED_SOIL_ WEATHER

FALSE Exposition to soil or weather to define cover and min Steel reinforcement

CONC_CLAS 1 Concrete class according to 1.4.1d) to define Modulus of Elasticity

LIGHT_CONC FALSE Light Concrete to define development multipliers according to table 3.1 NTC

COLD_FORM_BAR FALSE Cold formed Bar to define development multipliers according to table 3.1 NTC

DUCTILE_SEISMIC _DESIGN

TRUE DUCTILE FRAMES ACCORDING TO SECTION 5. Some design conditions are considered (not including, for the time being, geometric or confinment ones)

DIAM_AG *2 cm MAXIMUM DIAM AGGREGATE

BEARED_PERIM TRUE Slab beared perimeter. To calculate min steel required

according to 2.1.2


Section 11A

11-6



Name Value

DIRECT_COMP TRUE Beam Loads and reactions in direct compression Cl-2.1.5.a.I 2nd paragraph

PHI 90 degrees Stirrups angle with the axis of the element

TORSIONAL_

EQUILIBRIUM

FALSE Beam needed for torsional equilibrium Cl.2.1.6a) 2nd

paragraph

Pfact 1.0 Part of the longitudinal steel considered to reduce

shear. 0(zero) is on the safe side. Value between 1 and 0.

ZB 0.0 IDEM ACI

YB 0.0 IDEM ACI

EIT *198000 Kg/cm2

CONCRETE MODULUS OF ELASTICITY

* These values must be provided in the current unit system being used. ** When using metric bars for design, provide values for these parameters in actual „mm„ units instead of the bar number. The following metric bar sizes are available: 4.2mm, 6 mm, 8 mm, 10 mm, 12 mm, 16 mm, 20 mm, 25 mm, 32 mm, 40 mm, 50 mm and 60 mm.

11A.5 Beam Design


forces, all active beam loadings are prescanned to locate the

possible critical sections. The total number of sections considered

is 12 (twelve) unless this number is redefined with an NSECTION

parameter. All of these equally spaced sections are scanned to

determine moment and shear envelopes.

Design for Flexure

Reinforcement for positive and negative moments are calculated

on the basis of the section properties provided by the user. If the

section dimensions are inadequate to carry the applied load, that is

if the required reinforcement is greater than the maximum

allowable for the cross section, the program reports that beam fails

in maximum reinforcement. Rectangular sections are also designed

with compression reinforcement.

Section 11A

11-7

Effective depth is chosen as Total depth - (Clear cover + diameter

of stirrup + half the dia. of main reinforcement), and a tr ial value

is obtained by adopting proper bar sizes for the stirrups and main

reinforcements. The relevant clauses in Sections 1.5, 1.6, 2.1.1 -2-

5, 3.10 and 5.2.2 of NTC Concrete are utilized to obtain the actual

amount of steel required as well as the maximum allowable and

minimum required steel. These values are reported as ROW,

ROWMX and ROWMN in the output and can be printed using the

parameter TRACK 1.0 (see Table 10A.1). In addition, the

maximum, minimum and actual bar spacing are also printed.

It is important to note that beams are designed for flexural moment

MZ only. The moment MY is not considered in the flexural design.

Design for Shear


torsional moments. Shear forces are calculated at a distance

(d+SFACE) and (d+EFACE) away from the end nodes of the beam.

SFACE and EFACE have default values of zero unless provided

under parameters (see Table 10A.1). Note that the value of the

effective depth "d" used for this purpose is the update value and

accounts for the actual c.g. of the main reinforcement calculated

under flexural design. Clauses 2.1.5-6 and 5.2.4 of NTC Concrete

are used to calculate the reinforcement for shear forces and

torsional moments. Based on the total stirrup reinforcement

required, the size of bars, the spacing, the number of bars and the

distance over which they are provided are calculated. Stirrups due

to geometric conditions are assumed to be 2-legged, due to design

conditions could be 2 or 4-legged.

Design for Anchorage

In the output for flexural design, the anchorage details are also

provided. At any particular level, the START and END coordinates

of the layout of the main reinforcement is described along with the

information whether anchorage in the form of a hook or

continuation is required or not at these START and END points.

Note that the coordinates of these START and END points are

obtained after taking into account the anchorage requirements.


Section 11A

11-8

Anchorage length is calculated on the basis of the Clauses

described in Section 3.1 of NTC concrete. In case the program

selects 2 different diameters for the main or compression

reinforcement, only the anchorage for the largest diameter is

analyzed.

Output

Section 11A

11-9

ACTUAL OUTPUT FROM DESIGN

=====================================================================

BEAM NO. 1 DESIGN RESULTS - FLEXURE PER CODE NTC FOR THE DESIGN AND

CONSTRUCTION OF CONCRETE STRUCTURES,DDF LEN - 525.00(cm) FY - 4200. FC -

250. SIZE - 30.00 X 80.00(cm)

LEVEL HEIGHT BAR INFO FROM TO ANCHOR

(cm) (cm) (cm) STA END

_____________________________________________________________________ 1

4. 8 - -NUM, 5 0. 39. YES NO 1 4. 1 - -NUM,

4 0. 39. 2 8. 3 - -NUM, 5 0.

39. YES NO |------------------------------------------------------------

----| | CRITICAL MOMENT=5978000.50 Kg cm AT 0.00 (cm)LOAD 1|

| REQD STEEL= 24.41 (cm2)ROW=0.0109 ROWMX=0.0190 ROWMN=0.0026 |

| REQD COMP STEEL= 0.00 (cm2) |

| MAX/MIN/ACTUAL BAR SPACING= 24.14/ 3.18/ 3.45 (cm) |

| COMP MAX/MIN/ACTUAL BAR SPACING= 0.00/ 0.00/ 0.00 (cm) |

| BASIC/REQD. DEVELOPMENT LENGTH = 40.07/ 39.08(cm) |

|----------------------------------------------------------------| Cracked

Moment of Inertia Iz at above location = 1015658.4 cm^4 3 77. 10 - -

NUM, 4 0. 45. YES NO 4 73. 9 - -NUM, 4 0.

45. YES NO |-------------------------------------------------------------

---| | CRITICAL MOMENT=5978000.50 Kg cm AT 0.00 (cm)LOAD 1|

| REQD STEEL= 24.17 (cm2)ROW=0.0107 ROWMX=0.0190 ROWMN=0.0026 |

| REQD COMP STEEL= 0.00 (cm2) |

| MAX/MIN/ACTUAL BAR SPACING= 24.46/ 2.54/ 2.72 (cm) |

| COMP MAX/MIN/ACTUAL BAR SPACING= 0.00/ 0.00/ 0.00 (cm) |

| BASIC/REQD. DEVELOPMENT LENGTH = 32.00/ 44.81(cm) |

|----------------------------------------------------------------|Cracked Moment

of Inertia Iz at above location = 1008728.7 cm^4 REQUIRED REINF. STEEL SUMMARY :

-------------------------------

SECTION REINF STEEL(+VE/-VE) MOMENTS(+VE/-VE) LOAD(+VE/-VE)

( CM ) (SQ. CM ) (KG -CM )

0.00 24.67/ 24.67 5978000./ 5978000.50 0/ 0

525.00 24.67/ 24.67 5978000./ 5978000.50 0/ 0

B E A M N O. 1 D E S I G N R E S U L T S – SHEAR

AT START SUPPORT - Vu=41850.00 Kg Vc= 6074.49 Kg Vs=44719.39 Kg

Tu= 0.00 Kg cm Tc= 0.00 Kg cm Ts= 0.00 Kg cm LOAD 0

NO STIRRUPS ARE REQUIRED FOR TORSION.

REINFORCEMENT IS REQUIRED FOR SHEAR.

PROVIDE NUM. 2.5 2-LEGGED STIRRUPS AT 7.(cm) C/C FOR 176.(cm)

ADDITIONAL LONGITUDINAL STEEL REQD. FOR TORSIONAL RESISTANCE = 0.00 (cm2)

AT END SUPPORT - Vu=37450.00 Kg Vc= 6074.49 Kg Vs=39219.39 Kg

Tu= 0.00 Kg cm Tc= 0.00 Kg cm Ts= 0.00 Kg cm LOAD 0

NO STIRRUPS ARE REQUIRED FOR TORSION.

REINFORCEMENT IS REQUIRED FOR SHEAR.

PROVIDE NUM. 2.5 2-LEGGED STIRRUPS AT 8.(cm) C/C FOR 176.(cm)

ADDITIONAL LONGITUDINAL STEEL REQD. FOR TORSIONAL RESISTANCE = 0.00 (cm2)


Section 11A

11-10

11A.6 Column Design

Columns design in STAAD per the Mexican code is performed for

axial force and uniaxial as well as biaxial moments. All active

loadings are checked to compute reinforcement. The loading which

produces the largest amount of reinforcement is called the critical

load. Column design is done for square, rectangular and circular

sections. For rectangular and circular sections, reinforcement is

always assumed to be equally distributed on all faces. This means that

the total number of bars for these sections will always be a multiple

of four (4). If the MMAGx & -MMAGy parameters are specified, the

column moments are multiplied by the corresponding MMAG value to

arrive at the ultimate moments on the column. Minimum eccentricity

conditions to be satisfied according to section 2.1.3.a are checked.

Method used: Bresler Load Contour Method

Known Values: Pu, Muy, Muz, B, D, Clear cover, Fc, Fy

Ultimate Strain for concrete : 0.003

Steps involved :

1. Assume some reinforcement. Minimum reinforcement (1% for

ductile design or according to section 4.2.2 ) is a good amount

to start with.

2. Find an approximate arrangement of bars for the assumed

reinforcement.

3. Calculate PNMAX = Po, where Po is the maximum axial load

capacity of the section. Ensure that the actual nominal load on

the column does not exceed PNMAX. If PNMAX is less than

the axial force Pu/FR, (FR is the strength reduction factor)

increase the reinforcement and repeat steps 2 and 3. If the

reinforcement exceeds 6% (or 4% for ductile design), the

column cannot be designed with its current dimensions.

4. For the assumed reinforcement, bar arrangement and axial

load, find the uniaxial moment capacities of the column for the

Section 11A

11-11

Y and the Z axes, independently. These values are referred to

as MYCAP and MZCAP respectively.

5. Solve the Interaction Bresler equation:

Mny Mnz

+

Mycap Mycap

Where a = 1.24. If the column is subjected to uniaxial moment: a =1

6. If the Interaction equation is satisfied, find an arrangement

with available bar sizes, find the uniaxial capacities and solve

the interaction equation again. If the equation is satisfied now,

the reinforcement details are written to the output file.

7. If the interaction equation is not satisfied, the assumed

reinforcement is increased (ensuring that it is under 6% or 4%

respectively) and steps 2 to 6 are repeated.

By the moment to check shear and torsion for columns the sections

have to be checked as beams and the most strict of both shear and

torsion reinforcement adopted.

11A.7 Column Interaction

The column interaction values may be obtained by using the

design parameter TRACK 1.0 or TRACK 2.0 for the column

member. If a value of 2.0 is used for the TRACK parameter, 12

different Pn-Mn pairs, each representing a different point on the

Pn-Mn curve are printed. Each of these points represents one of

the several Pn-Mn combinations that this column is capable of

carrying about the given axis, for the actual reinforcement that the

column has been designed for. In the case of circular columns, the

values are for any of the radial axes. The values printed for the

TRACK 1.0 output are:


Section 11A

11-12

P0 = Maximum allowable pure axial load on the column (moment zero).

Pnmax = Maximum allowable axial load on the column.

P_bal = Axial load capacity of balanced strain condition.

M_bal = Uniaxial moment capacity of balanced strain condition.

E_bal = M_bal / P_bal = Eccentricity of balanced strain condition.

M0 = Moment capacity at zero axial load.

P_tens = Maximum permissible tensile load on the column.

Des. Pn = Pu/FR where FR is the Strength Reduction Factor and Pu is the axial

load for the critical load case.

Des.Mnx = Mux*MMAGx/FR where FR is the Strength Reduction Factor and Mu

is the bending moment for the appropriate axis for the critical load case.

Mu = (Mux.Mmagx)²+ (Muy.Mmagy)²

e/h = (Mn/Pn)/h where h is the length of the column

11A.8 Column Design Output

The next table illustrates different levels of the column design

output.

Section 11A

11-13

The output is generated without any TRACK specification:

====================================================================

COLUMN NO. 1 DESIGN PER - AXIAL + BENDING

FY -4200.0 FC - 294.1 Kg/cm2 CIRC SIZE 100.0(cm)DIAMETER

AREA OF STEEL REQUIRED = 128.506

BAR CONFIGURATION REINF PCT. LOAD LOCATION PHI

----------------------------------------------------------

46 - NUMBER 6 1.669 1 END 0.700

(EQUALLY SPACED)

TRACK=1 generates the following additional output:

COLUMN INTERACTION: MOMENT ABOUT Z/Y -AXIS (Kg-cm )

--------------------------------------------------------

P0 Pn max P-bal. M-bal. e-bal.(cm)

2095196.38 2095196.38 727411.12 29235398.00 40.2

M0 P-tens. Des.Pn 'Des.Mn e/h

20606994.00 -550620.00 0.00 20000000.00 NaN

--------------------------------------------------------

TRACK=2 generates the following output in addition to all the above:

Pn Mn Pn Mn

| 1934027.38 5373253.50 967013.69 27278232.00

P0 |* 1772858.50 11408365.00 805844.75 28658428.00

| * 1611689.50 16296947.00 644675.81 29473708.00

Pn,max|__* 1450520.62 20083028.00 483506.84 28901764.00

| * 1289351.62 23117562.00 322337.91 27205616.00

Pn | * 1128182.62 25462606.00 161168.95 24433192.00

NOMINAL| *

AXIAL| *

COMPRESSION| *

Pb|-------*Mb

| *

___________|____*_______

| * M0 Mn,

| * BENDING

P-tens|* MOMENT

11A.9 Slab Design

Slab are designed per Mexican NTC specifications. To design a

slab, it must be modeled using finite elements.

Element design will be performed only for the moments MX and

MY at the center of the element. Design will not be performed for

FX, FY, FXY, MXY. Also, design is not performed at any other

point on the surface of the element. Shear is checked with Q.

A typical example of element design output is shown below. The

reinforcement required to resist Mx moment is denoted as


Section 11A

11-14

longitudinal reinforcement and the reinforcement required to resist

My moment is denoted as transverse reinforcement. The

parameters FYMAIN, FC, CLEAR, DIM_PRECAUTION, and

EXPOSED_SOIL_WEATHER listed in Table 3.1 are relevant to

slab design. Other parameters mentioned are not used in slab

design.

ELEMENT DESIGN SUMMARY ----------------------

ELEMENT LONG. REINF MOM-X /LOAD TRANS. REINF MOM-Y /LOAD

(SQ.CM/M ) (T -M /M ) (SQ.CM/M ) (T -M /M )

1 TOP : Longitudinal direction - Only minimum steel required.

1 BOTT: Transverse direction - Only minimum steel required.

1 TOP : 2.239 0.00 / 0 3.252 983.00 / 1

BOTT: 3.758 983.00 / 1 1.684 0.00 / 0

1 SHEAR CAPACITY 3794.73 Kg ***PASS***

11-15

Steel Design per Mexican Code

11B.1 General

The program is based in: Complementary Technical Standards for

the Design and Construction of Steel Structures – Dec. 1987.

(Normas Técnicas Complementarias para Diseño y construcción de

Estructuras Metálicas) of the Mexican Construction Code for the

Federal District –Aug. 1993 (Reglamento de Construcciones para

el Distrito Federal).

The design philosophy considered is that of the Load Cases and

Resistance Method or Limit States Design usually known as Load

and Resistance Factor Design (LRFD).

Structures are designed and proportioned taking into consideration

the limit states at which they would become unfit for their

intended use. Two major categories of limit-state are recognized--

ultimate and serviceability. The primary considerations in ultimate

limit state design are strength and stability, while that in

serviceability is deflection. Appropriate load and resistance factors

are used so that a uniform reliability is achieved for all steel

structures under various loading conditions and at the same time

the chances of limits being surpassed are acceptably remote.

In the STAAD implementation of the Mexican Standards for steel

structures, members are proportioned to resist the design loads

without exceeding the limit states of strength, and stability. It

allows to check deformation to verify serviceability.

Accordingly, the most economic section is selected on the basis of

the least weight criteria as augmented by the designer in

Section 11B

Steel Design Per Mexican Code

Section 11B

11-16

specification of allowable member depths, desired section type, or

other such parameters. The code checking portion of the program

checks that main code requirements for each selected section are

met and identifies the governing criteria.

The following sections describe the salient features of the Mexican

specifications as implemented in STAAD steel design. A brief

description of the fundamental concepts is presented here.

11B.2 Limit States Design Fundamentals

The primary objective of the Limit States Design Specification is

to provide a uniform reliability for all steel structures under

various loading conditions.

The Limit States Design Method uses separate factors for each

load and resistance. Because the different factors reflect the degree

of uncertainty of different loads and combinations of loads and of

the accuracy of predicted strength, a more uniform reliability is

possible.

The method may be summarized by the inequality

Yi Qi < Rn FR

On the left side of the inequality, the required strength is the

summation of the various load effects, Qi, multiplied by their

respective load factors, yi. The design strength, on the right side,

is the nominal strength or resistance, Rn, multiplied by a

resistance factor, FR.

In the STAAD implementation of the Mexican Standards, it is

assumed that the user will use appropriate load factors and create

the load combinations necessary for analysis. The design portion

of the program will take into consideration the load effects (forces

and moments) obtained from analysis. In calculation of resistances

of various elements (beams, columns etc.), resistance (nominal

strength) and applicable resistance factor will be automatically

considered.

Section 11B

11-17

11B.3 Member End Forces and Moments

Member end forces and moments in the member result from loads

applied to the structure. These forces are in the local member

coordinate system. the following figures show the member end

actions with their directions.


Section 11B

11-18


The Limit States Design specification allows inelastic deformation

of section elements. Thus local buckling becomes an important

criterion. Steel sections are classified as compact (type 2),

noncompact (type 3), or slender element(type 4), sections

depending upon their local buckling characteristics, besides

sections type 1 are able for plastic design. This classification is a


procedures are different depending on the section class. STAAD is

capable of determining the section classification for the standard

shapes and design accordingly.

11B.5 Member in Axial Tension

The criteria governing the capacity of tension members is based on

two limit states. The limit state of yielding in the gross section is


second limit state involves fracture at the section with th e


by the user through the use of the parameter NSF (see Table

10B.1), that always refers to the gross section. STAAD calculates

the tension capacity of a given member based on these two limit

states and proceeds with member selection or code check

accordingly.

In addition to the tension resistance criterion, the user defines if

tension members are required to satisfy slenderness limitations

which are a function of the nature of use of the member (main load

resisting component, bracing member, etc.). In both the member

selection and code checking process, STAAD immediately does a

slenderness check on appropriate members before continuing with

other procedures for determining the adequacy of a given member.

Section 11B

11-19

11B.6 Axial Compression

The column strength equations take into account inelastic

deformation and other recent research in column behavior. Two

equations governing column strength are available, one for

inelastic buckling and the other for elastic or Euler buckling. Both

equations include the effects of residual stresses and initial out -of-

straightness. Compression strength for a particular member is

calculated by STAAD according to the procedure outlin ed in

Section 3.2 of the NTC. For slender elements, the procedure

described in Section 2.3.6.NTC is also used.

The procedures of Section 3.2 of the Commentaries, design helps

and examples of the Complementary Technical Standards for the

Design and Construction of Steel Structures (de los Comentarios,

ayudas de diseño y ejemplos de las Normas Técnicas

Complementarias para el Diseño y Construcción de Estructuras

Metálicas, DDF (Comentarios - Julio 1993) were implemented for

the determination of design strength for these limit states.

Effective length for calculation of compression resistance may be

provided through the use of the parameters KY, KZ and/or LY,

LZ. If not provided, the entire member length will be taken into

consideration.

In addition to the compression resistance criterion, compression

members are required to satisfy slenderness limitations which are a

function of the nature of use of the member (main load resisting

component, bracing member, etc.). In both the member selection

and code checking process, STAAD immediately does a

slenderness check on appropriate members before continuing with

other procedures for determining the adequacy of a given member.


Section 11B

11-20

11B.7 Flexural Design Strength

In the Limit States Design Method, the flexural design strength of

a member is determined mainly by the limit state of lateral

torsional buckling. Inelastic bending is allowed and the basic

measure of flexural capacity is the plastic moment capacity of the

section.

The flexural resistance is a function of plastic moment capacity,

actual laterally unbraced length, limiting laterally unbraced length,

buckling moment and the bending coefficient. The limiting

laterally unbraced length Lu and flexural resistance Mr are

functions of the section geometry and are calculated as per the

procedure of Section 3.3.2 of the NTC.

The purpose of bending coefficient Cb is to account for the

influence of the moment gradient on lateral-torsional buckling.

This coefficient can be specified by the user through the use of

parameter CB or CBy (see Table 10B.1) or may be calculated by

the program (according to LRDF USA specification) if CB is

specified as 0.0. In the absence of the parameter CB, a default

value of 1.0 will be used.

To specify laterally unsupported length, either of the parameters

UNL and UNF (see Table 10B.1) can be used.

It is taken into account the reduction of flexural resistance due to

slender web according to section 4.5.8 of the NTC

For the sections where the web and flange are slender the LRDF

USA specification was used.

Section 11B

11-21

Stress areas due to bending about y axis (MY)

Notes: the local X axis goes into the page; the Global Y axis is

vertical upwards; the shaded area indicates area under

compression; the area not shaded indicates area under tension.

Stress areas due to bending about Z axis (MZ)


Section 11B

11-22

11B.8 Design for Shear

The procedure of Sect. 3.3.3 of the NTC is used in STAAD to

design for shear forces in members. Besides combined bending and

shear is checked according to section 3.3.4 of the NTC,

considering also the limits for stiffeners of the web according to

sections 4.5.6/7 of the NTC. Shear in wide flanges and channel

sections is resisted by the area of the web/s..

11B.9 Combined Compression Axial Force and Bending

The interaction of flexure and axial forces in singly and doubly

symmetric shapes is governed by formulas of the Section 3.4 of

the NTC. These interaction formulas cover the general case of

biaxial bending combined with axial force. They are also valid for

uniaxial bending and axial force.

It is considered that the frames are part of structures that have

shear walls or rigid elements so that the lateral displacements of a

floor could be disregarded. The program has included for mulas to

include structures with lateral displacements in the future

considering for B2 the columns individually and not the complete

floor analysis.

It is taken into account if the elements have transverse loads and if

the ends are angularly restrained.

11B.10 Combined Tension Axial Force and Bending

Based on Section 3.5 4 of the NTC.

Section 11B

11-23


Design per Mexican Standards is requested by using the CODE.

Other applicable parameters are summarized in Table 10B.1. These

parameters communicate design decisions from the engineer to the

program and thus allow the engineer to control the design process

to suit an application's specific needs.





The parameters DMAX and DMIN may only be used for member

selection only.





Section 11B

11-24

TABLA 11B.1. DESIGN PARAMETERS ACCORDING TO MEXICAN

STANDARS - STEEL


Name Value

KX 1.0 K value for flexural-torsional buckling

KY 1.0 K value in local Y axis- Usually minor axis

KZ 1.0 K value in local Z axis- Usually major axis

LX Member length Length for flexural-torsional buckling

LY Member length Length to calculate slenderness ratio for buckling

about local Y axis.

LZ Member length Length to calculate slenderness ratio for buckling about local Z axis.

FYLD 2530 kg/cm2 Minimum Yield strength of steel

FU 4230 Kg/cm2 Ultimate tensile strength of steel

NSF 1 Net section factor for tension members

UNT Member length Unsupported length (L) of the top* flange for calculating flexural strength . Will be used only if compression is in the top flange.

UNB Member length Unsupported length (L) of the bottom* flange for calculating flexural strength . Will be used only if compression is in the bottom flange.

STIFF Member length Spacing of stiffeners for beams for shear design

Cb y Cby 1 Coefficient C defined per section 3.3.2.2. If Cb is set to 0.0 it will be calculated by the program according to LRFD USA (CbMex=1/CbUSA). Any other value will be directly used in the design.

TRACK 0 0 = Suppress all design strengths

1 = Print all design strengths

2 = Print expanded design output

DMAX 114 cm Maximum allowable depth

DMIN 0.0 cm Minimum allowable depth

RATIO 1.0 Permissible ratio of actual load effect and design

strength

BEAM 0 0: Design at ends and those locations specified by SECTION command.

1: Design at ends and at every y cada 1/12th point along member length

Rigid_to_H_Loads TRUE Defines if the structure has elements to bear the wind load ( shear walls, wind trusses or bracing

Section 11B

11-25


STANDARS - STEEL


Name Value

rigid elements ) that restrict lateral displacements

and allow to disregard slenderness effects.

IRREG 0 Variable defined for the whole structure indicating if it is regular or irregular according

to section 3.4 of the NTC. IRREG=1 for columns being part of irregular structures.

I_NO_OXIG 0 Defined for I shapes or tubes

Curve Definition according to NTC.3.2.2.1a) I_NO_OXIG.= 0 implies n=1.4 laminated I shapes, tubes or built up with 3 or 4 welded plates obtained from wider plates cuts with oxygen. I_NO_OXIG.= 1 implies n=1 I shapes, tubes or built up with 3 or 4 welded plates

n is defined by the program

IMAIN_MEM 0 IMAIN_MEM=0 MAIN MEMBER IMAIN_MEM=1 Secondary and wind trusses

Ccomb 1 Cfactor for combined forces when there are transverse loads in the members. Section 3.4.3.3.ii NTC Ccomb=1 If members ends are restricted

angularly. Ccomb=0.85 If members ends are not restricted angularly.

DUCTILE_SEISMIC

_DESIGN

TRUE DUCTILE FRAMES ACCORDING TO

SECTION 11. Main design conditions are considered (not including, at the moment, geometric ones)

KX 1.0 K value for flexural-torsional buckling

KY 1.0 K value in local Y axis- Usually minor axis

KZ 1.0 K value in local Z axis- Usually major axis

LX Member length Length for flexural-torsional buckling

LY Member length Length to calculate slenderness ratio for buckling

about local Y axis.

LZ Member length Length to calculate slenderness ratio for buckling about local Z axis.

FYLD 2530 kg/cm2 Minimum Yield strength of steel

FU 4230 Kg/cm2 Ultimate tensile strength of steel


Section 11B

11-26


STANDARS - STEEL


Name Value

NSF 1 Net section factor for tension members

UNT Member length Unsupported length (L) of the top* flange for calculating flexural strength . Will be used only

if compression is in the top flange.

UNB Member length Unsupported length (L) of the bottom* flange for calculating flexural strength . Will be used only

if compression is in the bottom flange.

STIFF Member length Spacing of stiffeners for beams for shear design

Cb y Cby 1 Coefficient C defined per section 3.3.2.2. If Cb is set to 0.0 it will be calculated by the program according to LRFD USA (CbMex=1/CbUSA). Any other value will be directly used in the design.

TRACK 0 0 = Supress all design strengths

1 = Print all design strengths

2 = Print expanded design output

DMAX 114 cm Maximum allowable depth

DMIN 0.0 cm Minimum allowable depth

RATIO 1.0 Permissible ratio of actual load effect and design

strength

BEAM 0 0: Design at ends and those locations specified by SECTION command.

1: Design at ends and at every y cada 1/12th point along member length

Rigid_to_H_Loads TRUE Defines if the structure has elements to bear the wind load ( shear walls, wind trusses or bracing rigid elements ) that restrict lateral displacements and allow to disregard slenderness effects.

IRREG 0 Variable defined for the whole structure indicating if it is regular or irregular according to section 3.4 of the NTC. IRREG=1 for columns being part of irregular structures.

I_NO_OXIG 0 Defined for I shapes or tubes Curve Definition according to NTC.3.2.2.1a) I_NO_OXIG.= 0 implies n=1.4

laminated I shapes, tubes or built up with 3 or 4 welded plates obtained from wider plates cuts with oxygen.

Section 11B

11-27


STANDARS - STEEL


Name Value

I_NO_OXIG.= 1 implies n=1

I shapes, tubes or built up with 3 or 4 welded plates n is defined by the program

IMAIN_MEM 0 IMAIN_MEM=0 MAIN MEMBER

IMAIN_MEM=1 Secondary and wind trusses

Ccomb 1 Cfactor for combined forces when there are transverse loads in the members. Section

3.4.3.3.ii NTC Ccomb=1 If members ends are restricted angularly. Ccomb=0.85 If members ends are not restricted angularly.

DUCTILE_SEISMIC _DESIGN

TRUE DUCTILE FRAMES ACCORDING TO SECTION 11. Main design conditions are considered (not including, at the moment, geometric ones)

* Top and Bottom represent the positive and negative side of the local Y axis (local

Z axis if SET Z UP is used.

Note: For deflection check, parameters DFF, DJ1 and DJ2 from Table 2.1 may be

used. All requirements remain the same.



STAAD Mexican Standards implementation.


Section 11B

11-28



tabular format.

CRITICAL COND refers to the section of the Mexican NTC which


If the TRACK is set to 1.0, member design strengths will be

printed out.

Section 12

Russian Codes

12-1

Concrete Design Per Russian Code (SNiP 2.03.01-84*)

12A.1 General

Russian Code SNiP 2.03.0184* “Plain concrete and concrete

structures” is based on the method of limit states. Code SNiP

2.03.0184* defines two groups of limit states.

Analysis according to the first group of limit states is performed to

avoid the following phenomena:

brittle, plastic or other type of failure,

loss by structure of stable form or position,

fatigue failure,

failure due to the action of load actions and unfavourable

environmental effects.

Analysis according to the second group of limit states is performed

to avoid the following phenomena:

excessive and longterm opening of cracks if they are allowed

according to service conditions,

excessive displacements.

Analysis of structures for the first group of limit states is

performed with the use of the maximum (design) loads and

actions. Analysis of structures for the second group of limit states

is made in accordance with the operational (normative) loads and

actions. Ratio between design and normative loads is called

reliability coefficient for loads which is determined according to

SNiP 2.01.07.-85 “Loads and actions”.

Section 12A

Concrete Design Per Russian Code

Section 12A

12-2

Reliability coefficient n for destination according to SNiP

2.01.07.-85 shall be considered in determination of loads and their

combinations.

Program STAAD/Pro makes it possible to calculate reinforcement

for concrete members according to codes of many countries round

the World and Russian Code SNiP 2.03.0184* inclusive.

Algorithms for calculation of reinforcement of concrete linear

(beams, columns) and 2D (two dimensional) (slabs, walls, shells)

members are incorporated in program STAAD/Pro. Not only Code

SNiP 2.03.0184* but also the “Guide for design of plain concrete

and reinforced concrete structures from normal weight and

lightweight concrete (to SNiP 2.03.0184)” have been used in

creation of these algorithms.

It is possible using program STAAD/Pro to calculate

reinforcement for beams of rectangular or T section and for

columns of rectangular or circular section (Fig.1).

Figure 1 - Notation of dimensions for rectangular, circular and T sections

Flange of T-shape beams may be situated at the top zone of the

section if the angle BETA=00, or at the bottom zone of the section,

if BETA=1800.

Section 12A

12-3

12A.2 Input Data

Entry of data of cross-sections of beams and columns is made by

the use of MEMBER PROPERTIES command, and thicknesses of

2D members are entered by ELEMENT PROPERTY command.

Example:

UNIT MM

MEMBER PROPERTIES

* Columns of rectangular cross-section

1 TO 16 PRI YD 350. ZD 350.

* Columns of circular cross-section

17 TO 22 PRI YD 350.

* Beams of T cross-section

23 TO 40 PRI YD 450. ZD 550. YB 230. ZB 200.

UNIT METER

ELEMENT PROPERTY

41 TO 100 THICKNESS 0.14

101 TO 252 THICKNESS 0.16

* Flange of T beams is located at the bottom zone of

cross-section

BETA 180. MEMB 23 TO 40

Commands for calculation of reinforcement are located in the

input data file after the command of analysis and as a rule, after

output commands to print results of calculation.

Example:

* Command of analysis PERFORM ANALYSIS

.

.* Output command to print results of calculation

(according to user’s judgment)

.


Section 12A

12-4

* Command of loading and their combinations

considered in design

LOAD LIST 1 5 TO 9

* Command to start reinforcement calculation procedure


CODE RUSSIAN

.* List of parameters being used in reinforcement

calculation

.

.

BCL 20. MEMB 17 TO 22

CL1 0.04 MEMB 1 TO 40

DD2 10. MEMB 23 TO 40

CRA 0.036 MEMB 41 TO 252

.

.

.

* Command of beam reinforcement calculation

DESIGN BEAM 23 TO 40

* Command of column reinforcement calculation


* Command of calculation 2D elements (slabs, walls,

shells)


* Command of interruption reinforcement calculation

END CONCRETE DESIGN

In tables 1, 2 and 3 information about parameters used for

calculation of reinforcement for beams, columns and 2D (two

dimensional) members is presented. Values of parameters do not

depend on UNIT command. In the file of input data only such

parameters have to be taken, the values of which differ from

determined in the program.

Section 12A

12-5




Table 1- Names of parameters for Concrete design according to Russian Code

СНиП 2.03.0184* for beams.

No. Parameter

name

Default

value Description

1 NLT 1 Number of long-term loading case

2 RCL 3

Class of longitudinal reinforcement:

RCL = 1, if class of reinforcement is A-I;

RCL = 2, if class of reinforcement is A-II;

RCL = 3, if class of reinforcement is A-III;

RCL = 33, if class of reinforcement is A-IIIb;

RCL = 4, if class of reinforcement is A-IV;

RCL = 5, if class of reinforcement is A-V;

RCL = 6, if class of reinforcement is A-VI;

RCL = 7, if class of reinforcement is A-VII;

RCL = 77, if class of reinforcement is K-7;

RCL = 8, if class of reinforcement is B-II;

RCL = 9, if class of reinforcement is Bp-II;

RCL = 10, if class of reinforcement is Bp-I;

RCL = 19, if class of reinforcement is K-19

3 USM 1. Total product of service conditions coefficients for

longitudinal reinforcement (s)

4 UB2 0.9 Specific service conditions coefficient for concrete

(b2)

5 DD1 16. Diameter of longitudinal reinforcement bars in

beam tension zone

6 DD2 16. Diameter of shear reinforcement bars for beam;

7 BCL 15. Compression class of concrete

8 UBM 1. Product of service conditions coefficients for

concrete, except UB2 (b)

9 TEM 0.

Parameter of concrete hardening conditions:

TEM=0, for natural hardening conditions;

TEM=1, for steam hardening conditions

10 CL1 0.05 Distance from top/bottom fiber of beam cross


Section 12A

12-6

No. Parameter

name

Default

value Description

section to the center of longitudinal reinforcement

bar;

11 CL2 0.05 Distance from left/right side of beam cross section

to the center of longitudinal reinforcement bar

12 WST 0.4 Ultimate width of short-term crack

13 WLT 0.3 Ultimate width of long-term crack

14 SSE 0

Limit state parameter for beam design

SSE=0, if calculation of reinforcement

amount must be carried out according to the

requirements of load carrying capacity (the

first limit state);

SSE=1, if calculation of reinforcement

amount must be carried out according to the

cracking requirements (the second limit

state)

15 RSH 1

Class of shear reinforcement:

RSH = 1, if class of reinforcement is A-I;

RSH = 2, if class of reinforcement is A-II;

RSH = 3, if class of reinforcement is A-III;

RSH = 33, if class of reinforcement is A-

IIIb;

RSH = 4, if class of reinforcement is A-IV;

RSH = 5, if class of reinforcement is A-V;

RSH = 6, if class of reinforcement is A-VI;

RSH = 7, if class of reinforcement is A-VII;

RSH = 77, if class of reinforcement is K-7;

RSH = 8, if class of reinforcement is B-II;

RSH = 9, if class of reinforcement is Bp-II;

RSH = 10, if class of reinforcement is Bp-I;

RSH = 19, if class of reinforcement is K-19

16 FWT ZD

Design width of beam top flange. Use for beam

design only with default value provided as ZD in

member properties.

17 FWB ZB

Design width of beam bottom flange. Use for beam

design only with default value provided as ZB in

member properties.

Section 12A

12-7

No. Parameter

name

Default

value Description

18 DEP YD

Design depth of beam section. Use for beam

design only with default value provided as YD in

member properties.

19 SFA 0. Face of support location at the start of the beam.

Use for beam design only.

20 EFA 0. Face of support location at the end of the beam.

Use for beam design only.

21 NSE 13

Number of equally-spaced sections for beam

design. Use for beam design only. Upper limit is

equal to 20.

Table 2 - Names of parameters for Concrete design according to Russian Code

СНиП 2.03.0184* for columns

No. Parameter

name

Default

value Description


2 RCL 3





RCL = 33, if class of reinforcement is A-IIIb;


RCL = 5, if class of reinforcement is A-V;








3 USM 1. Total product of service conditions coefficients for

longitudinal reinforcement (s)

4 UB2 0.9 Specific service conditions coefficient for concrete

(b2)

5 DD1 16. Minimum diameter of longitudinal reinforcement


Section 12A

12-8

No. Parameter

name

Default

value Description

bars for column

6 DD2 16. Maximum diameter of longitudinal reinforcement

bars for column




9 TEM 0.




10 CL1 0.05 Distance from edge of column cross section to the

center of longitudinal reinforcement bar

11 ELY 1. Column's length coefficient to evaluate

slenderness effect in local Y axis

12 ELZ 1. Column's length coefficient to evaluate

slenderness effect in local Z axis

Тable 3 - Names of parameters for Concrete design according to Russian Code

(SNiP 2.03.01-84*) for slabs and/or walls

No. Parameter

name

Default

value Description


2 RCL 3





RCL = 33, if class of reinforcement is A-

IIIb;


RCL = 5, if class of reinforcement i s A-V;







Section 12A

12-9

No. Parameter

name

Default

value Description


3 USM 1. Total product of service conditions coefficients

for longitudinal reinforcement (s)

4 UB2 0.9 Specific service conditions coefficient for

concrete (b2)

5 SDX 16. Diameter of reinforcing bars located in the first

local (X) direction of slab/wall

6 SDY 16. Diameter of reinforcing bars located in the

second local (Y) direction of slab/wall




9 TEM 0.




10 CL 0.05

Distance from top/bottom face of slab/wall

element to the center of longitudinal reinforcing

bars located in first local (X) direction. (Main

thickness of top/bottom concrete cover for

slab/wall element)

11 CRA 0.05

Distance from top/bottom face of slab/wall

element to the center of transverse reinforcing

bars located in second local (Y) direction

(Secondary thickness of top/bottom concrete

cover for slab/wall)

12 WST 0.4 Ultimate width of short-term crack

13 WLT 0.3 Ultimate width of long-term crack

14 STA 0

Parameter of limit state for slab/wall design:

STA=0, if calculation of nonsymmetrical

reinforcement must be carried out according

to the requirements of load carrying capacity

(the first limit state);

STA=1, if calculation of symmetrical

reinforcement must be carried out according

to the requirements of load carrying capacity

(the first limit state);


Section 12A

12-10

No. Parameter

name

Default

value Description

STA=2, if calculation of nonsymmetrical

reinforcement must be carried according to

the cracking requirements (the second limit

state);

STA=3, if calculation of symmetrical

reinforcement must be carried according to

the cracking requirements (the second limit

state)

15 SELX 0. Design length of wall member to evaluate

slenderness effect in local X axis

16 SELY 0. Design length of wall member to evaluate

slenderness effect in local Y axis

17 MMA 0

Design parameter of slab/wall reinforcement:

MMA=0, if reinforcement calculation must

be applied by stresses in local axis;

MMA=1, if reinforcement calculation must

be applied by principal stresses

18 MMB 1

Design parameter of slab/wall reinforcement:

MMB=0, if the effect of additional

eccentricity is not taken into account;

MMB=1, if the effect of additional

eccentricity is taken into account

12A.3 Beams

Reinforcement for beams of rectangular and T cross-section can be

calculated. In calculation of longitudinal reinforcement bending

moment about local axis Z loc and torsional moments are

considered, but influence of longitudinal forces and bending

moments in relation to local axis Yloc is ignored. In calculation of

transverse reinforcement shear forces parallel to local axis Yloc and torsional moments are taken into account.

Section 12A

12-11

Reinforcement for beams can be calculated either from conditions

of strength or from conditions of open crack width limitation (see

parameter SSE).

Parameters SFA and ЕFA are considered only in calculation of

transverse reinforcement.

In general case calculation of reinforcement for beams is carried

out two times – according to strength conditions and according to

conditions of open crack width limitation. In reinforcement

calculations from conditions of strength design values of load have

to be taken and in calculations from conditions of crack width

limitation – characteristic (normative) load values are used. Both

calculations can be carried out in one session with the use multiple

analysis possibility of the program STAAD.Pro.

In most cases calculation of reinforcement is carried out with

account only of a part of loadings. In such cases command LOAD

LIST is used, in which numbers of loads considered in calculation

are indicated. Number of permanent and long-term loads equal to

parameter NLT must be included into the list of considered loads.

It has to be noted, that values of parameters DD1 and DD2 have

influence not only on the width of opened crack but also in som e

cases, on design and normative reinforcement resistances.

Parameter BCL can be equal to any value of concrete compression

strength class given in SNiP 2.03.0184* and to any intermediate

value as well.

It should be remembered, that accuracy of results of calculation of

transverse reinforcement increases with the value of parameter

NSE.

Parameters SFA and ЕFA are considered only in calculations of

transverse reinforcement. Beam 1 is shown in Figure 2 with rigid

intervals the lengths of which are: at the start of the beam 0.3m

and at the end – 0.2m. In modeling of the beam the following

command can be used.


Section 12A

12-12

MEMBER OFFSET

1 START 0.3 0 0

1 END -0.2 0 0

Figure 2 - Diagram of a beam with rigid intervals

When command MEMBER OFFSET is used forces corresponding

to the beam the length of which is equal to the distance between

points a and b are calculated and then used in calculation of

reinforcement. In such case it is necessary to take into account

default values of parameters SFA and ЕFA equal to zero.

When command MEMBER OFFSET is not used forces

corresponding to the beam the length of which is equal to the

distance between points 10 and 11 are calculated and then used in

calculation of reinforcement. In this case it is necessary to

consider values of parameters SFA=0.3 and ЕFA=0,2 in

reinforcement calculation.

In both cases calculated quantity of transverse reinforcement will

be the same. Calculated quantity of longitudinal reinforcement in

the second case will be greater.

For beam the following output is generated:

beam number;

method of calculation (according to conditions of strength

or limitations of opened crack width);

length and cross-sectional dimensions;

distance from resultant of forces acting in bottom/top

reinforcement to bottom/top edge of the section;

Section 12A

12-13

distance from the side edge of cross-section of the beam

web to the centroid of longitudinal bars located at this

edge;

concrete class;

class of longitudinal and transverse reinforcement;

assumed in calculations bar diameters of longitudinal and

transverse reinforcement;

calculation results of longitudinal and transverse

reinforcement (in two tables).

In nine columns of the first table the following results are

presented:

Section distance of the section from the “start” of the

beam, мм

As cross-sectional area of longitudinal

reinforcement in the bottom zone of cross-

section of the beam, if angle BETA=0, or in the

top zone, if BETA=180 , sq.cm

As cross-sectional area of longitudinal

reinforcement in the top zone of cross-section of

the beam , if angle BETA=0, or in the top zone,

if BETA=180 , sq.cm

Moments (/) values of bending moments, determining cross-

sectional areas of longitudinal reinforcement As

and As , kNm

Load. N. (/) numbers of loading versions, determining cross-

sectional areas of longitudinal reinforcement

Acrc1 short-term opened crack width*, mm

Acrc2 long-term opened crack width*, mm

* Opened crack width is presented only in the case when calculation is

performed according to conditions limiting opened crack width.


Section 12A

12-14

In ten columns of second table the following results are presented:


beam, mm

Qsw intensity of transverse reinforcement, kN/m

Asw cross-sectional area of transverse bars, sq.cm, if

their step is 10, 15, 20, 25 or 30 cm

Q value of shear force parallel to the local axis, kN

T value of torsional moment, kNm

Load N. number of loading version, determining intensity

of transverse reinforcement

An example of output of calculation results is presented below.

BEAM NO. 23 DESIGN RESULTS

(by limitation of crack width)

Length 6000 mm.

Section: BF1= 550 mm, B= 200 mm, HF1=220 mm, H=450 mm.

Distance from top/bottom surface of beam to center of longitudinal

reinforcement 40 mm.

Distance from side surface of beam to center of longitudinal

reinforcement 30 mm.

Concrete class В25.0 (Rb=13.05 MPa; Rbt=0.94 MPa; Gb2=0.9).

Class of longitudinal reinforcement АIII (Rs=365.0 MPa;

Rsc=365.0 MPa).

Diameter of longitudinal reinforcement bars D=16 mm.

Class of shear reinforcement АI (Rsw=175.0 MPa).

Diameter of shear reinforcement bars Dw=10 mm.

Section 12A

12-15

L O N G I T U D I N A L R E I N F O R C E M E N T

Section As- As+ Moments( -/+) Load.N.(-/+) Acrc1 Acrc2

mm sq.cm kNm mm mm

0.

10.92 0.41 152.

/ 2. 6 / 4 0.237 0.121

500.

4.74 0.41 60.

/ 0. 5 / 0 0.294 0.157

1000.

1.13 1.13 5.

/ 17. 4 / 6 0.000 0.000

1500.

1.13 6.41 8.

/ 75. 4 / 6 0.295 0.147

2000.

1.13 9.24 11.

/ 115. 4 / 6 0.298 0.149

2500.

1.13 11.53 14.

/ 139. 4 / 6 0.271 0.134

3000.

1.19 12.16 18.

/ 144. 4 / 6 0.263 0.127

3500.

1.41 10.86 21.

/ 132. 4 / 6 0.277 0.130

4000.

1.63 8.28 24.

/ 103. 4 / 6 0.296 0.129

4500.

1.95 4.54 27.

/ 56. 4 / 6 0.299 0.093

5000.

3.23 0.58 39.

/ 9. 5 / 3 0.293 0.157

5500.

0.74 0.41 124.

/ 0. 5 / 0 0.271 0.142

6000.

16.89 0.41 226.

/ 0. 5 / 0 0.155 0.078


Section 12A

12-16

S H E A R R E I N F O R C E M E N T

Section Qsw Asw, cm^2, if Sw= Q T Load

mm kN/m 10cm 15cm 20cm 25cm 30cm kN kNm N.

0. 251.3 1.44 2.15 2.87 3.59 4.31 203.9 0.0 6

500. 251.3 1.44 2.15 2.87 3.59 4.31 168.9 0.0 6

1000. 174.5 1.00 1.50 1.99 2.49 2.99 133.9 0.0 6

1500. 63.9 0.36 0.55 0.73 0.91 1.09 98.9 0.0 6

2000. Minimum detailing requirements ! 63.9 0.0 6





4500. 95.0 0.55 0.82 1.09 1.37 1.64 117.7 0.0 5

5000. 242.5 1.39 2.08 2.77 3.46 4.16 152.7 0.0 5

5500. 302.5 1.73 2.59 3.46 4.32 5.19 187.7 0.0 5

6000. 302.5 1.73 2.59 3.46 4.32 5.19 216.1 0.0 5

Here Minimum detailing requirements! means that reinforcement is

not required according to calculation.

122A.4 Columns

Reinforcement for columns of rectangular or circular cross -section

can be calculated. Flexibility of columns can be evaluated in two

ways. In the case of usual analysis (command PERFORM

ANALYSIS) flexibility is assessed by parameters ELY and ELZ,

values of which should conform with recommendation of the Code

SNiP 2.03.0184*. If PDELTA (analysis according to deformed

diagram) or NONLINEAR (nonlinear geometry) analysis is

performed, values of parameters ELY and ELZ should be close to

zero, for example ELY = ELZ=0.01.

Longitudinal reinforcement for columns is calculated only from

condition of strength. Longitudinal forces and bending moments in

Section 12A

12-17

relation to local axes Yloc and Z loc are taken into account in

longitudinal reinforcement calculations.

For rectangular columns the following output is generated:

column number;

column length and cross-sectional dimensions;

distance of centroid of each longitudinal bar from the

nearest edge of the cross-section;

concrete class;

longitudinal reinforcement class;

range of longitudinal reinforcement bar diameters assumed

in calculation;

diameter of longitudinal reinforcement bars obtained in

calculation;

total quantity of longitudinal bars;

quantity of longitudinal bars at each cross-section edge,

directed parallel to the local axis Yloc ;

quantity of longitudinal bars at each cross-section edge,

directed parallel to the local axis Z loc .

In nine columns of the table under the heading LONGITUDINAL

REINFORCEMENT the following output is presented:


column, mm

Astot total cross-sectional area of longitudinal

reinforcement, sq.cm

Asy cross-sectional area of longitudinal

reinforcement bars at each edge of section,

directed parallel to the local axis Yloc , sq.cm

Asz cross-sectional area of longitudinal

reinforcement bars at each edge of section,

directed parallel to the local axis Z loc , sq.cm

Percent reinforcement percentage in the section

Nx, Mz, My respective values of longitudinal force and

bending moments in relation to the local axes

Z loc and Yloc , determining cross-sectional area


Section 12A

12-18

of longitudinal reinforcement

Load.N. number of loading version, determining cross-

sectional area of longitudinal reinforcement

An example of output of calculation results is presented below.

COLUMN NO. 97 DESIGN RESULTS

(rectangular section)

Length 4000 mm.

Section: B= 350 mm, H=350 mm.

Distance from edge of column cross section to center of each

longitudinal

reinforcement bar 40 mm.

Concrete class В25.0 (Rb=13.05 МPa; Gb2=0.9).

Class of longitudinal reinforcement АIII (Rs=365.0 МPa;

Rsc=365.0 МPa).

Diameter range of longitudinal reinforcement bars:

Dmin=16 mm . . . Dmax=32 mm

Diameter of longitudinal reinforcement bars from calculation d=20

mm.

Total number of reinforcement bars Ntot=6.

Number of longitudinal bars at each section edge parallel to the

local Y axis Nyy =2.

Number of longitudinal bars at each section edge parallel to the

local Z axis Nzz =3.


Section Astot Asy Asz Per cent Nx Mz My Load

m sq.cm sq.cm sq.cm % kN kNm kN m N.

0.

16.42

3.01

6.20

1.34

285.5

81.9

0.0

6

4000.

15.35

3.01

5.67

1.25

397.3

95.3

0.0

5

Section 12A

12-19

Diameter of longitudinal reinforcement bars, total quantity of

longitudinal bars as well as quantity of longitudinal bars at each

edge of the section obtained from calculation should be considered

as recommendation. In this case arrangement of reinforcement in

the section depends on the orientation of the local axes and is as

follows:

or

Calculated values of reinforcement cross-sectional areas are

presented in the table and they may differ from recommended on

the lower side.

When it is not possible according to detailing provisions to arrange

in the column longitudinal reinforcement determined from

calculation additional message is derived.

For columns of circular section the following output is generated:

column number;

column length and diameter of cross-section;

distance of centroid of each longitudinal bar to the edge of

cross-section;

longitudinal reinforcement class;

assumed in calculation range of diameters of longitudinal

reinforcement bars;

diameter of longitudinal reinforcement bars obtained from

calculation;

quantity of longitudinal bars.


Section 12A

12-20

In seven columns of the table under the heading LONGITUDINAL

REINFORCEMENT the following results are presented:


column, mm

Astot total cross-sectional area of longitudinal

reinforcement, sq.cm

Per cent percentage of longitudinal reinforcement

Nx, Mz, My respective values of longitudinal force and

bending moments in relation to local axis Z loc

and Yloc , determining cross-sectional area of

longitudinal reinforcement

Load. N. number of loading version, determining cross-

sectional area of longitudinal reinforcement

An example of output of calculation results for a column of

circular section is presented below.

COLUMN NO. 80 DESIGN RESULTS

(circular section)

Length 4000 mm.

Diameter: Dс= 350 mm.

Distance from edge of column cross section to center of each

longitudinal

reinforcement bar 50 mm.

Concrete class В20.0 (Rb=10.35 МPa; Gb2=0.9).

Class of longitudinal reinforcement АIII (Rs=365.0 МPa;

Rsc=365.0 МPa).

Diameter range of longitudinal reinforcement bars:

Dmin=16 mm . . . Dmax=32 mm

Diameter of longitudinal reinforcement bars from calculation

D=20 mm.

Total number of reinforcement bars Ntot =7.

Section 12A

12-21


Section Astot Per cent Nx Mz My Load. N.

mm sq.cm % kN kNm kNm

0. 17.96 1.87 195.1 59.8 0.0 5

4000. 21.86 2.27 195.1 80.2 0.0 5

Diameter of longitudinal reinforcement bars, total quantity of

longitudinal bars as well as quantity of longitudinal bars at each

edge of the section should be considered as recommendation.

Arrangement of reinforcement in section in this case is shown

below:

Calculated cross-sectional areas of reinforcement presented in the

table may differ from recommended on the lower side.

When according to detailing provisions it is not possible to arrange

in the column longitudinal reinforcement obtained from

calculation additional message is derived.

12A.5 2D (two dimensional) element (slabs, walls, shells)

In general case calculation of reinforcement for 2D members is

carried out two times – according to conditions of strength and

conditions of limiting opened width of cracks. If reinforcement is

calculated according to conditions of strength, design values of

loads have to be used, and for conditions of limiting crack width –

characteristic (normative) loads are employed. Both calculations

can be made in one session taking advantage of multiple analysis

possibility of the program STAAD.Pro.


Section 12A

12-22

Symmetric or nonsymmetric reinforcement of 2D members is

calculated according to conditions of strength or according to

conditions of limiting opened crack width (see for example STA).

In reinforcement calculation for 2D members it is necessary to pay

attention to arrangement of local axes of member and direction of

reinforcement (see for example CL and CRA).

An example of output of calculation results is presented bellow.

SLAB/WALL DESIGN RESULTS

(by stresses in local axes for limitation of crack width)

Element Asx Mx Nx Load. N. Asy My Ny Load N.

sq.cm/m kNm/m kN/m (X) sq.cm/m kNm/m kN/m (Y)

60 TOP 0.00 - 4.9 0.0 1 0.00 - 4.5 0.0 1

BOT 3.53 - 9 .9 0.0 3 3.46 - 8.9 0.0 3

61 TOP 0.00 - 5 .3 0.0 1 0.00 - 4.7 0.0 1

BOT 3.87 - 10.7 0.0 3 3.65 - 9.4 0.0 3

62 TOP 0.00 - 5 .6 0.0 1 0.00 - 4.8 0.0 1

BOT 4.10 - 11.2 0.0 3 3.77 - 9.6 0.0 3

Section 12A

12-23

Here:

Element number of finite element, TOP “top” zone of

member, BOT “bottom” zone of member (“top”

zone of member is determined by positive direction of

local axis Z loc see Fig.2)

Asx intensity of reinforcing in the first direction (parallel

to the local axis X loc ), sq.cm/m

Mx distributed bending moment in respect to the local

axis Yloc , kNm/m

Nx distributed longitudinal force directed parallel to the

axis X loc , kNm/m

Load N.(X) number of loading version, determining intensity of

reinforcing in the first direction

Asy intensity of reinforcing in the second direction

(parallel to the local axis Yloc ), sq.cm/m

My distributed bending moment in respect to the local

axis X loc kNm/m

Ny distributed longitudinal force directed parallel to the

local axis Yloc kN/m

Load N.(Y) number of loading version, determining intensity of

reinforcing in the second direction


Section 12A

12-24

Figure 2 - Local coordinate system of 2D member and notation of forces

12-25

Steel Design Per Russian Code SNIP 2.23-81* (Edition 1990)

12B.1 General

Design Code SNiP “Steel Structures” as majority of modern codes

is based on the method of limit states. The following groups of

limit states are defined in the Code.

The first group is concerned with losses of general shape

and stability, failure, qualitative changes in configuration

of structure. Appearance of non-allowable residual

deformations, displacements, yielding of materials or

opening of cracks.

The second group is concerned with states of structures

making worse normal their service or reducing durability

due to not allowable deflections, deviations, settlements,

vibrations, etc.

Analysis of structures for the first limit state is performed using

the maximum (design) loads and actions, which can cause failure

of structures.

Analysis of structures for the second limit state is performed using

service (normative) loads and actions. Relation between design

and normative loads is referred to as coefficient of load reliability,

which is defined in SNiP 2.01.07.- 85 “Loads and Actions”.

Coefficient of reliability for destination GAMA n according to

SNiP 2.01.07.- 85 shall be taken in to account determining loads or

their combinations.

Section 12B

Steel Design Per Russian Code

Section 12B

12-26

In this version of the program only members from rolled, tube and

roll-formed assortment sections and also from compound such as

double angles of T-type sections, double channels are presented.

Design of other members of compound section will be presented in

other versions of the program.

Economy of selected section is indicated by ratio (RATIO) /Ryyc

presented in calculation results. A section is economical when said

ratio equals to 0,9 – 0,95.

12B.2 Axial tension members

Stress in a section of axial tension member shall not exceed design

strength Ry of selected steel multiplied by coefficient of service

conditions c (KY and KZ), table 6 of SNiP 2.01.07. - 81*.

Slenderness of tension member (CMM) shall not exceed

slenderness limit indicated in table 20 of SNiP 2.01.07. - 81*

(default value u=200, but another value can be defined). Net

section factor (ratio Anet/Agross (NSF)) is used for tension member

to allow for reduction of design cross-section area.

12B.3 Axial compression members

All axial compression members are calculated as long bars, i.e.,

with allowance for slenderness (=l0/imin). Calculation is

performed in accordance with the clause 5.3 of SNiP 2.01.07. -

81*, buckling coefficient is determined by formula 8-10.

Effective bar lengths (within and out of plane) taking in to account

role and location of the bar in the structure, as well as fixation of

ends (l0=l), are determined according to requirements of chapter

6 or addition 6 to SNiP 2.01.07.- 81* and are set by specification

of members. Slenderness of compression members (CMN) shall

not exceed limit values given in table 19 of SNiP 2.01.07.- 81*.

Value of coefficient being used in table 19 is taken within limits

from 0,5 to 1,0. Limit slenderness value depends on stress acting

in the member, section area, buckling coefficient and design

resistance of steel.

Section 12B

12-27

Since slenderness can be different in various planes the greatest

slenderness is assumed in calculations.

12B.4 Flexural members

Members subjected to the action of bending moments and shear

forces are called flexural members.

Calculation of flexural members consists of verification of

strength, stability and deflection.

Normal and tangential stresses are verified by strength calculation

of members. Normal stresses are calculated in the outermost

section fibres. Tangential stresses are verified in the neutral axis

zone of the same section. If normal stresses do not exceed design

steel strength and tangential stresses do not exceed design value of

steel shear strength Rss then according to clause 5.14 of SNiP

2.01.07.- 81* principal stresses are checked.

General stability of member subjected to bending in one plane are

calculated in accordance with clause 5.15 of SNiP 2.01.07. - 81*,

and subjected to bending in two planes – in accordance with

“Guide to design of steel structures” (to SNiP 2.01.07. - 81*).

Coefficient b value is determined according to appendix 7 of

SNiP 2.01.07.- 81*. Additional data about load (concentrated or

distributed), numbers of bracing restrains of compression flanges,

location of applied load are required. For closed sections it is

assumed that coefficient b=1,0.

Simply supported (non-continuous) beams can be calculated in

elastic as well as in elastic-plastic state according to requirements

of clause 5.18 of SNiP 2.01.07.- 81*. Calculation can be selected

by specification of structure in input data.


Section 12B

12-28

Stiffness of flexural members is verified comparing input value of

deflection limit (through parameter DFF) with maximum

displacement of a section of flexural member allowing for load

reliability coefficient, which is specified, in input data. Limit

values of deflection are determined in accordance with SNiP

2.01.07.- 85 “Loads and Actions. Addition chapter 10. Deflections

and displacements”. Verification of deflection is performed only in

the case of review (CHECK) problem.

12B.5 Eccentrical compression/tension members

Eccentrical compression or tension members are subjected to

simultaneous action of axial force and bending moment. Bending

moment appears due to eccentrical application of longitudinal

force or due to transverse force.

Stress in eccentrical compression/tension members is obtained as a

sum of stresses due to axial force and bending.

Following the requirements of clause 5.25 of SNiP 2.01.07.- 81*

resistance of eccentrical compression/tension member taking into

consideration condition Ry<530 MPa, <0,5Rs and N/(AnRy)>0,1 is

calculated by formula 49, and in other cases-by formula 50.

Calculations of stability verification are performed according to

requirements of clauses 5.27, 5.30, 5.32 or 5.34.

Calculation for strength of eccentrical tension members is made

according to formula 50 of SNiP 2.01.07.- 81*.

When reduced relative eccentricity m ef>20 eccentrical compression

members are calculated as flexural members (N=0), when m ef<20

strength by formula 49 is not verified (clause 5.24).

Section 12B

12-29

12B.6 Input Data

Program STAAD/Pro gives opportunity to verify sections of steel

structures by codes of many countries including and Russian Code

SNiP 2.01.07.- 81*. Algorithms for selection and review of

sections for steel members according to assortments and databases

of the main rolled steel producers from given countries and

according to international standards as well are included in

STAAD/Pro program. In this program version only assortment

sections can be utilized.

Typical sections of members being checked and selected according

to SNiP 2.01.07.- 81* are presented in tables 1 and 2.

Table 1. Typical sections

No

. Section Section type Designation form

1 I-beam (GOST 8239-89)

ST I12

2 Regular I-beam (GOST 26020-

83) ST B1-10

3 Broad-flanged I-beam (GOST

26020-83) ST SH1-23

4 Column I-beam (GOST 26020-

83) ST K1-20

5 Channel (GOST 8240-89)

ST C14


Section 12B

12-30

Table 1. Typical sections

No


6 Equal legs angle (GOST 8509-

89)

ST L100x100x7

RA L100x100x7

7 Unequal legs angle (GOST

8510-89)

ST L125x80x10

RA L125x80x10

8 Pipes (welded and for gas

piping)

ST PIP102x5.5

or

ST PIPE OD 0.102 ID

0.055

9 Roll-formed square and

rectangular tubes

ST TUB160x120x3

or

ST TUBE TH 0.003

WT 0.12 DT 0.16

Section 12B

12-31

Table 2. Compound sections

No


1 Double channels

D C14 SP 0.01

(SP – clear distance

between channel walls)

2 Double equal legs angles

LD L100x100x7 SP

0.01


between angle walls)

5 Double unequal legs angles with

long legs back to back

LD L125x80x10 SP

0.01



6 Double unequal legs angles with

short legs back to back

SD L125x80x10 SP

0.01



7 Tee with flange at the top

T I12

T B1-10

T SH1-23

T K1-20

Flange of Tee beams is at the top part of cross-section if angle

BETA = 0, or at the bottom part if BETA = 180.

For entry of cross-sectional dimensions command MEMBER

PROPERTIES RUSSIAN is used.


Section 12B

12-32

Example

UNITS METER

MEMBER PROPERTY RUSSIAN

* I-beam

1 TO 6 TABLE ST B1-10

* Channel

7 TO 11 TABLE ST C14

* Unequal legs angle

12 TO 30 TABLE RA L125x80x10

* Round assortment pipe

31 TO 46 TABLE ST PIP102x5.5

* Round pipe of cross-sectional dimensions defined by

client

47 TO 60 TABLE ST PIPE OD 0.102 ID 0.055

* Square tube from assortment

61 TO 68 TABLE ST TUB120x120x3

* Rectangular tube of cross-sectional dimension defined

by client

69 TO 95 TABLE ST TUBE TH 0.003 WT 0.12 DT 0.16

* Double channel (distance between walls 10 мм)

96 TO 103 TABLE D C14 SP 0.01

* Double unequal legs angles with short legs back to

back (distance between walls 10 мм)

104 TO 105 TABLE SD L125x80x10 SP 0.01

* Member of Tee section

106 TO 126 TABLE T SH1-23

* Flange of T-beams at the bottom of cross-section

BETA 180. MEMB 116 TO 126

* Orientation of the local angle axes in relation to the

global axes of the structure

BETA RANGLE MEMB 12 TO 30

Commands of output data for check and selection of sections are

located after commands of analysis and, as a rule, after output

command to print results of calculation.

Section 12B

12-33

Example

* Command of analysis

PERFORM ANALYSIS

* Command of loadings and their combinations

considered in design

LOAD LIST 1 5 TO 9

* Command to start design according to Russian Code

PARAMETER

CODE RUSSIAN

* List of parameters used in checking and selecting

.

BEAM 1. ALL (obligatory parameter) .

LY 4. MEMB 1 TO 4

LZ 4. MEM 1 TO 4

MAIN 1. ALL

SGR 3. ALL

SBLT 0 ALL

* Parameter of output amount of information on

calculation results

TRACK 2. ALL

.

* Command to start section check procedure

CHECK CODE ALL

* Command to start section selection procedure

SELECT ALL

.

* Command of output to print content of assortment

tables

PRINT ENTIRE TABLE

* Command of output to print summary of steel according

to sections

STEEL TAKE OFF

* Command of output to print summary of steel according

to members and sections

STEEL MEMBER TAKE OFF


Section 12B

12-34

Information on parameters, data used for check and selection of

sections in design of steel structures according to Russian Code is

presented in table 3.

In this version of calculation according to requirements of SNiP

2.01.07.- 81* there is common database of equal legs angles and

unequal legs angles, therefore solution of section selection

problem may give equal legs angle as well as unequal legs angle

irrespective of set at the beginning. The same is and with

rectangular and square tubes.

Values of parameters do not depend on command UNIT. Only

these values of parameters, which differ from, defined in the

program need to be included in the input data file.

Review of sections (command CHECK) can be performed

according to the first and the second group of limit states.

Selection of section (command SELECT) can be performed only

according to the first group of limit states with subsequent

recalculation and verification of selected section with allowance

for deflection.

Calculation for the first group of limit states involves selection of

members according to strength and stability. Parameters CMN and

CMM give opportunity to set slenderness limit for compression

and tension members respectively for their stability calculation, or

refuse consideration of slenderness by setting default parameters.

In this case selection of sections will be performed with

consideration only of strength check.

Check for deflection performed by setting parameter DFF

(maximum allowable relative deflection value) different from set

in the program.

In the case of application of steel not defined by SNiP and/or

GOST it is necessary to set their design strength by parameters

UNL and PY.

Section 12B

12-35

In determination of steel parameters SBLT and MAIN shall be

approved (see table 4). Note: Once a parameter is specified, its



Table 3. Names of parameters for Steel design according

to Russian Code (SNiP II – 23 – 81*, edition 1990)

No. Parameter

name Description

Default

value

1 KY

Coefficient of effective length in

respect to local axis Y (in plane

XZ)

1.0

2 KZ

Coefficient of effective length in

respect to local axis Z (in plane

XY)

1.0

3 LY

[m]

Effective length in respect to local

axis Y (in plane XZ)

Default is selected member's

length

Member

length

4 LZ

[m]

Effective length in respect to local

axis Z (in plane XY)

Default is selected member's

length

Member

length

5 SBLT

Number of lateral bracing

restraints along the span:

SBLT = 0, if beam not

fixed;

SBLT = 1, one restraint in

the middle of the span;

SBLT = 2, 3, etc. number

of uniformly spaced

lateral supports along the

span

0

6 NSF

Net section factor for tension

members or web section area

weakening factor for bending

members

1.0


Section 12B

12-36



No. Parameter

name Description

Default

value

7 MAIN

Standard of steel grade (GOST):

MAIN = 1, if Standard of

steel grade is

GOST27772-88;


steel grade is

GOST10705-80;


steel grade is

GOST10706-76;


steel grade is GOST8731-

87;


steel grade is TY14-3-567-

76

1

8 DFF

Allowable limit of relative local

deflection (Member

length/Deflection Ratio):

Default value 0 is valid if design

is applied without deflection

limitation.

Set for deflection check only

0.

Section 12B

12-37



No. Parameter

name Description

Default

value

9 SGR

Steel grade (STAL):

SGR = 1, if Steel grade is

C235;


C245;


C255;


C275;


C285;


C345;


C345K;


C375;


C390;


C390K;


C440;


C590;


C590K;


BCT3KP;


BCT3PC;


BCT3CP;


20;

1


Section 12B

12-38



No. Parameter

name Description

Default

value


16G2AF

10 СMM

Slenderness limit value for tension

members:

СMM = 0, if

slenderness is

suppressed;

СMM = 2, if

ultimate

slenderness value

is "150";

СMM = 2, if

ultimate

slenderness value

is "200";

СMM = 3, if

ultimate

0

Section 12B

12-39



No. Parameter

name Description

Default

value

slenderness value

is "250";

СMM = 4, if

ultimate

slenderness value

is "300";

СMM = 5, if

ultimate

slenderness value

is "350";

СMM = 6, if

ultimate

slenderness value

is "400

Set slenderness limit value not

equal to "0" for design with

evaluation of buckling effect

11 CMN

Slenderness limit value for

compression members:

СMN = 0, if

slenderness is

suppressed;

СMN = 1, if

slenderness limit

value is "120";

СMN = 2, if

slenderness limit

value is "210-

60a";

СMN = 3, if

slenderness limit

value is "220-

40a";

СMN = 4, if

slenderness limit

0


Section 12B

12-40



No. Parameter

name Description

Default

value

value is "220";

СMN = 5, if

slenderness limit

value is "180-

60a";

СMN = 6, if

slenderness limit

value is "210-

60a";

СMN = 7, if

slenderness limit

value is "210-

60a";

СMN = 8, if

slenderness limit

value is "200";

СMN = 9, if

slenderness limit

value is "150";

Set slenderness limit value not

equal to "0" for design with

evaluation of buckling effect

12 LEG

Type and position of loading on

beam:

LEG = 1, for loading

concentrated in the middle

span;


concentrated in the quarter

of the span;


concentrated at the end of

bracket;


uniformly distributed on

4

Section 12B

12-41



No. Parameter

name Description

Default

value

beam;


uniformly distributed on

bracket

13 CB

Place of loading on beam:

CB = 1, for loading on

top flange;

CB = 2, for loading on

bottom flange

1

14 TRACK

Output parameter:

TRACK = 0, for

suppressed output

information;

TRACK = 1, for

extended output

information;

TRACK = 2, for

advanced output

information

0

15 TB

Indication of elastic or elastic-

plastic calculation:

TB = 0, for elastic

calculation

TB = 1, for elastic-plastic

calculation

Set for members under bending or

non-axial compression/tension

only.

0

16 RATIO Ratio between design and

characteristic loads values 1.0


Section 12B

12-42



No. Parameter

name Description

Default

value

17 DMAX

[m] Maximum allowable section depth 1.

18 DMIN

[m] Minimum allowable section depth 0.

19 BEAM

Member design parameter:

BEAM = 0, Design

members for forces at

their ends or at the

sections defined by

SECTION command;

BEAM = 1, Calculate the

major axis moment Mz at

13 points along the beam

and design beam at the

location of maximum Mz;

BEAM = 2, Same as

BEAM=1, but additional

checks are carried out at

beam ends and at critical

inter mediate section;

BEAM = 3, Calculate

forces at 13 points and

perform design checks at

all locations including the

ends

1

20 GAMC1 Specific service condition

coefficient for buckling design 1.0

21 GAMC2 Specific service condition

coefficient for strength design 1.0

22 PY

[MPa]

Design steel strength (yield

strength):

If parameters MAIN according to

Standard of steel grade (GOST)

0

Section 12B

12-43



No. Parameter

name Description

Default

value

and by SGR according to Steel

grade (STAL) are not defined

23 UNL

[MPa]

Design steel strength (ultimate

strength):

If parameters MAIN according to

Standard of steel grade (GOST)

and by SGR according to Steel

grade (STAL) are not defined

0


Section 12B

12-44

Table 4. Steel types for design of steel structures

according to SNiP 2.01.07.- 81* (table 51 and 51a)

Parameter

SGR Steel

Parameter

MAIN GOST

For members

*

1 C235 1 GOST

27772-88

GT, F

2 C245 1 “ GT, F

3 C255 1 “ GT, F

4 C275 1 “ GT, F

5 C285 1 “ GT, F

6 C345 1 “ GT, F

7 C345K 1 “ GT, F

8 C375 1 “ GT, F

9 C390 1 “ F

10 C390K 1 “ F

11 C440 1 “ F

12 C590 1 “ F

13 C590К 1 “ F

14 BSt3kp 2 GOST

10705-

80*

Tube

15 BSt3ps 2

3

GOST

10705-

80*

GOST

10706-

76*

Tube

16 BSt3sp 2

3

GOST

10705-

80*

GOST

10706-

76*

Tube

17 20 4 GOST

8731-87

Tube

18 16G2АF 5 TY 14-3-

567-76

Tube

*GT – members from sheet and roll-formed tubes

F – rolled section steel

Section 12B

12-45

12B.7 Section selection and check results

Output of selection and check results are given in suppressed,

extended and advanced forms. Form of output results depends on

value of parameter TRACK.

Results are presented in tables. Three versions of output results are

possible: suppressed – results according the critical strength

condition (TRACK=0), extended - results according to all check

conditions (TRACK=1) and advanced – complete information on

results of member design (TRACK=2).

In tables of results common data for all TRACKs are indicated:

(TRACK=2).

In tables of results common data for all TRACKs are indicated:

number of member;

type and number of cross-section;

result obtained (ACCEPTED – requirements are met, FAILURE –

are not met);

abbreviated name of normative document (code, standard) (SNiP);

number of check clause;

safety of strength (ratio between design and normative values);

number of the most unfavorable loading;

value of longitudinal force acting in the member with subscript

indicating its direction (“C” – compression, “P” – tension);

bending moments in relation to local member axes Z and Y;

distance to section, in which the most unfavorable combination of

forces acts.


Section 12B

12-46

In suppressed form (TRACK=0) results are presented according to

the critical check for given member with indication of SNiP clause

number, according to which strength safety of the member is

minimum.

Example of output with TRACK=0 of calculation results of a

member is given below.

ALL UNITS ARE - KN METE

==============================================================

MEMBER CROSS RESULT/ CRITICAL COND/ RATIO/ LOADING/

SECTION NO. FX MZ MY LOCATION

==============================================================

1 B1-30 PASS SNiP- 5.12 0.73 2

0.000E+00 -8.750E+01 0.000E+00 4.167E+00

In extended form (TRACK=1) results are presented on the

basis of all required by SNiP checks for given stress state.


member is given below.


==============================================================



==============================================================

1 B1-30 PASS SNiP- 5.12 0.73 2

0.000E+00 -8.750E+01 0.000E+00 4.167E+00

1 B1-30 PASS SNiP- 5.12 0.06 2

0.000E+00 -8.750E+01 0.000E+00 4.167E+00

1 B1-30 PASS SNiP- 5.14 0.97 2

0.000E+00 -8.750E+01 0.000E+00 4.167E+00

1 B1-30 PASS SNiP- 5.15 0.84 2

0.000E+00 -8.750E+01 0.000E+00 4.167E+00

* 1 B1-30 FAIL SNiP- DISPL 1.59 2

0.000E+00 -8.750E+01 0.000E+00 4.167E+00

Section 12B

12-47

In advanced form (TRACK=2) in addition to tabled results

supplementary information is presented.

Material characteristics:

Steel;

Design resistance;

Elasticity modulus;

Section characteristics:

Length of member;

Section area;

Net area;

Inertia moment (second moment of area) (I);

Section modulus (W);

First moment of area (S);

Radius of gyration;

Effective length;

Slenderness;

Results are presented in two columns, Z and Y respectively.

Design forces:

Longitudinal force;

Moments;

Shear force.

Signs “+” and “-“ indicate direction of acting longitudinal force,

bending moments and shear forces in accordance with sign rules

assumed in program STAAD.

Check results in advanced form are presented with values of

intermediate parameters by formulas in analytical and numerical

expression with indication of SNiP clause.


member is given in the next page.


Section 12B

12-48


========================================================================



========================================================================

1 B1-30 PASS SNiP- 5.12 0.73 2

0.000E+00 -8.750E+01 0.000E+00 4.167E+00

1 B1-30 PASS SNiP- 5.12 0.06 2

0.000E+00 -8.750E+01 0.000E+00 4.167E+00

1 B1-30 PASS SNiP- 5.14 0.97 2

0.000E+00 -8.750E+01 0.000E+00 4.167E+00

1 B1-30 PASS SNiP- 5.15 0.84 2

0.000E+00 -8.750E+01 0.000E+00 4.167E+00

* 1 B1-30 FAIL SNiP- DISPL 1.59 2

0.000E+00 -8.750E+01 0.000E+00 4.167E+00

MATERIAL DATA

Steel = C285

Modulus of elasticity = 206.E+06 KPA

Design Strength (Ry) = 280.E+03 KPA

SECTION PROPERTIES (units - m)

Member Length = 1.00E+01

Gross Area = 4.19E-03

Net Area = 4.19E-03

z-axis y-axis

Moment of inertia (I) : 633.E-07 390.E-08

Section modulus (W) : 428.E-06 557.E-07

First moment of area (S) : 240.E-06 415.E-07

Radius of gyration (i) : 123.E-03 305.E-04

Effective Length : 100.E-01 333.E-02

Slenderness : 0.00E+00 0.00E+00

DESIGN DATA (units -kN,m)SNiP II-23-81*/1998

Axial force : 0.00E+00

z-axis y-axis

Moments : -875.E-01 0.00E+00

Shear force : 0.00E+00 -150.E-01

CRITICAL CONDITIONS FOR EACH CLAUSE CHECK

F.(28) M/Wmin=-875.0E-01/ 4.28E-04= 204.6E+03

F.(29) (QY*SZ)/(IZ*TW)=-150.0E-01* 2.40E-04/ 6.33E-05* 5.80E-03= 980.9E+01

RS*GAMAC= 162.4E+03

F.(33) SQRT(SIGMz**2+3*TAUzy**2)<=1.15*RY*GAMAC

-312.5E+03**2+3* 980.9E+01**2<=1.15* 280.0E+03* 100.0E-02

313.0E+03<= 322.0E+03

TAUzy<=RS*GAMAC

980.9E+01<= 162.4E+03

F.(34) M/(FIB*Wmin)=-875.0E-01/ 8.75E-01* 4.28E-04= 234.0E+03

RY*GAMAC= 280.0E+03

ACTUAL SECTION DISPLACEMENT = 6.349E-02 M

MAXIMUM MEMBER DEFLECTION = 6.349E-02 M Loading No. 2

ULTIMATE ALLOWABLE DEFLECTION VALUE = 4.000E-02 M

Conventional notations assumed in presentation of results: “+”, “ -

“, “/”, “*”,”**”, “SQRT”, their respective meanings – addition,

subtraction, division, multiplication, raising to the second power

(squared) and square root. Conventional notations of stresses,

coefficients and characteristics of steel resistance comply with

accepted in SNiP, only Greek letters are changed by their names

(e.g. , с-GAMAC; -ALFA; -BETA, -ETA, -FI, etc.).

Section 13

South African

Codes

13-1

Concrete Design Per SABS 0100-1


STAAD has the capability for performing design of concrete

beams and columns according to the South African code SABS

0100-1. The 2000 revision of the code is currently implemented.

Design can be performed for beams (flexure, shear and torsion)

and columns (axial load + biaxial bending). Given the width and

depth (or diameter for circular columns) of a section, STAAD will

calculate the required reinforcement.



perform and control the design to SABS 0100-1. These parameters

not only act as a method to input required data for code

calculations but give the engineer control over the actual design

process. Default values of commonly used parameters for

conventional design practice have been chosen as the basis. Table

12A.1 contains a complete list of avai lable parameters with their

default values. Note: Once a parameter is specified, its value

stays at that specified number till it is specified again. This is

the way STAAD works for all codes.

Section 13A

South African Concrete Code Per SABS 0100-1

Section 13A

13-2

Table 13A.1 – South African Concrete Design-SABS 0100-1 -Parameters Parameter Default Description Name Value FYMAIN *450 N/mm2 Yield Stress for main reinforcement FYSEC *450N/mm2 Yield Stress for secondary reinforcement a.

Applicable to shear bars in beams FC * 30N/mm2 Concrete Yield Stress / cube strength MINMAIN 8mm Minimum main reinforcement bar size

Acceptable bar sizes: 6 8 10 12 16 20 25 28 32 36 40 50 60



CLT 20mm Clear Cover for outermost top reinforcement CLB 20mm Clear Cover for outermost bottom

reinforcement CLS 20mm Clear Cover for outermost side

reinforcement TRACK 0.0 0.0 = Critical Moment will not be printed with

beam design report. Column design gives no detailed results. 1.0 = For beam gives min/max steel % and spacing. For columns gives a detailed table of output with additional moments calculated. 2.0 = Output of TRACK 1.0 List of design sag/hog moments and corresponding required steel area at each section of member



Section 13A

13-3

Table 13A.1 – South African Concrete Design-SABS 0100-1 -Parameters Parameter Default Description Name Value BRACE 0.0 0.0 = Column braced in both directions.

1.0 = Column braced about local Y direction only 2.0 = Column unbraced about local Z direction only 3.0 = Column unbraced in both Y and Z directions



* Provided in current unit system




command. The following example demonstrates the required

input:

UNIT MM

MEMBER PROPERTIES

*RECTANGULAR COLUMN 300mm WIDE X 450mm DEEP

1 3 TO 7 9 PRISM YD 450. ZD 300.

*CIRCULAR COLUMN 300mm diameter

11 13 PR YD 300.

* T-SECTION - FLANGE 1000.X 200.(YD-YB)

* - STEM 250(THICK) X 350.(DEEP)

14 PRISM YD 550. ZD 1000. YB 350. ZB 250.


Section 13A

13-4


(450mm depth x 300mm width) and the second set of members,


circular with 300mm diameter. Note that area (AX) is not provided

for these members. If shear area areas (AY & AZ ) are to be

considered in analysis, the user may provide them along with YD

and ZD. Also note that if moments of inertias are not provided, the

program will calculate them from YD and ZD. Finally a T section

can be considered by using the third definition above.

13A.4 Beam Design

Beam design includes flexure, shear and torsion. For all types of


moment and shear envelopes and locate the critical sections. The

total number of sections considered is thirteen. From the critical


developed. Design for flexure is carried out as per clause no.

4.3.3.4.

Shear design as per SABS 0100 clause 4.3.4 has been followed and

the procedure includes computation of critical shear values. From

these values, stirrup sizes are calculated with proper spacing. If

torsion is present, the program will also consider the provisions of

SABS 0100 clause 4.3.5. Torsional reinforcement is separately

reported.

Section 13A

13-5

A TRACK 2 design output is presented below .

B E A M N O. 4 D E S I G N R E S U L T S


LENGTH: 7500.0 mm SIZE: 380.0 mm X 715.0 mm COVER: 25.0 mm

DESIGN LOAD SUMMARY (KN MET)

--------------------------------------------------------------------

SECTION |FLEXURE (Maxm. Sagging/Hogging moments)| SHEAR

(in mm) | MZ Load Case MX Load Case | VY P Load Case

--------------------------------------------------------------------

0.0 | 135.75 5 -3.44 5 | 152.06 50.62 4

| -295.92 4 |

625.0 | 189.16 5 -3.43 5 | 133.95 48.87 4

| -236.52 4 |

1250.0 | 231.25 5 -3.41 5 | 115.84 47.12 4

| -188.44 4 |

1875.0 | 262.01 5 -3.40 5 | 97.73 45.37 4

| -151.68 4 |

2500.0 | 281.46 5 -3.39 5 | 79.61 43.63 4

| -126.24 4 |

3125.0 | 289.59 5 -3.37 5 | 61.50 41.88 4

| -112.12 4 |

3750.0 | 286.39 5 -3.36 4 | -62.13 40.13 5

| -109.32 4 |

4375.0 | 271.88 5 -3.37 4 | -80.25 41.88 5

| -117.84 4 |

5000.0 | 246.05 5 -3.39 4 | -98.36 43.63 5

| -137.68 4 |

5625.0 | 208.89 5 -3.40 4 | -116.47 45.37 5

| -168.84 4 |

6250.0 | 160.42 5 -3.41 4 | -134.58 47.12 5

| -211.33 4 |

6875.0 | 100.62 5 -3.43 4 | -152.70 48.87 5

| -265.13 4 |

7500.0 | 29.50 4 -3.44 4 | -170.81 29.63 4

| -330.25 5 |

SUMMARY OF REINF. AREA FOR FLEXURE DESIGN (Sq.mm)

--------------------------------------------------------------------

SECTION | TOP | BOTTOM | STIRRUPS

(in mm) | Reqd./Provided reinf. | Reqd./Provided reinf. | (2 legged)

--------------------------------------------------------------------

0.0 | 1232.70/1256.64( 4-20í )| 543.40/ 565.50( 5-12í )| 8í @ 425 mm

625.0 | 960.90/ 981.74( 2-25í )| 754.32/ 791.70( 7-12í )| 8í @ 510 mm

1250.0 | 751.24/ 791.70( 7-12í )| 937.49/ 942.48( 3-20í )| 8í @ 510 mm

1875.0 | 596.52/ 603.18( 3-16í )| 1075.72/1206.36( 6-16í )| 8í @ 510 mm

2500.0 | 543.40/ 565.50( 5-12í )| 1165.13/1206.36( 6-16í )| 8í @ 510 mm

3125.0 | 543.40/ 565.50( 5-12í )| 1203.00/1206.36( 6-16í )| 8í @ 220 mm

3750.0 | 543.40/ 565.50( 5-12í )| 1188.08/1206.36( 6-16í )| 8í @ 220 mm

4375.0 | 543.40/ 565.50( 5-12í )| 1120.87/1206.36( 6-16í )| 8í @ 220 mm

5000.0 | 543.40/ 565.50( 5-12í )| 1003.50/1005.30( 5-16í )| 8í @ 220 mm

5625.0 | 668.18/ 678.60( 6-12í )| 839.38/ 904.80( 8-12í )| 8í @ 220 mm

6250.0 | 849.99/ 904.80( 8-12í )| 632.84/ 678.60( 6-12í )| 8í @ 220 mm

6875.0 | 1089.94/1206.36( 6-16í )| 543.40/ 565.50( 5-12í )| 8í @ 220 mm

7500.0 | 1397.16/1407.42( 7-16í )| 543.40/ 565.50( 5-12í )| 8í @ 220 mm

--------------------------------------------------------------------

TORSION REINFORCEMENT: Not required


Section 13A

13-6

13A.5 Column Design




critical load and is displayed. The requirements of SABS 0100-1

clause 4.7 are followed, with the user having control on the

effective length in each direction by using the ELZ and ELY

parameters as described in table 12A.1. Bracing conditions are



requires additional moment calculations. For biaxial bending, the

recommendations of 4.7.4.4 of the code are considered.

Column design is done for square, rectangular and circular

sections. For rectangular and square sections, the reinforcement is

always assumed to be arranged symmetrically. This causes slightly

conservative results in certain cases. Table 12A.3 shows typical

column design results.

Using parameter TRACK 1.0, the detailed output below is

obtained. TRACK 0.0 would merely give the bar configuration,

required steel area and percentage, column size and critical load

case.

Section 13A

13-7

TABLE 12A.3 -COLUMN DESIGN OUTPUT

=======================================================================

C O L U M N N O. 1 D E S I G N R E S U L T S


LENGTH: 3660.0 mm CROSS SECTION: 750.0 mm X 460.0 mm COVER:40.0mm

** GUIDING LOAD CASE: 4 END JOINT: 1 SHORT COLUMN

DESIGN FORCES (KNS-MET)

-----------------------

DESIGN AXIAL FORCE (Pu) : 915.6

About Z About Y

INITIAL MOMENTS : 0.00 0.00

MOMENTS DUE TO MINIMUM ECC. : 18.31 18.31

SLENDERNESS RATIOS : 7.96 4.88

ADDITION MOMENTS (Maddz and Maddy) : 0.00 0.00

TOTAL DESIGN MOMENTS : 555.13 21.91

REQD. STEEL AREA : 3349.20 Sq.mm.

REQD. CONCRETE AREA: 114451.62 Sq.mm.

MAIN REINFORCEMENT : Provide 32 - 12 dia. (1.05%, 3619.20 Sq.mm.)

(Equally Distributed)

TIE REINFORCEMENT : Provide 8 mm dia. rectangular ties @ 140 mm c/c

SECTION CAPACITY BASED ON REINFORCEMENT REQUIRED (KNS-MET)

----------------------------------------------------------

Puz : 2160.42 Muz1 : 570.23 Muy1 : 563.74


Section 13A

13-8

13-9

Steel Design Per SAB Standard SAB0162–1: 1993

13B.1 General

The South African Steel Design facility in STAAD is based on the

SAB Standard SAB0162-1: 1993, Limit States Design of Steel

Structures. A steel section library consisting of South African

Standards shapes is available for member property specification.




















criteria.

Section 13B

South African Steel Code Per SAB Standard SAB0162–1: 1993 Section 13B

13-10


implementation of SAB0162-1: 1993. A detailed description of the












analysis results.















Section 13B

13-11

I Shapes

The following example illustrates the specification of I- shapes.

1 TO 15 TABLE ST IPE-AA100

H shapes

Designation of H shapes in STAAD is as follows.

For example,

18 TO 20 TABLE ST 152X37UC

PG shapes

Designation of PG shapes in STAAD is as follows.

100 TO 150 TABLE ST 720X200PG

Channel Sections (C & MC shapes)

C and MC shapes are designated as shown in the following

example.

3 TABLE ST 127X64X15C

Double Channels


them, are specified by preceding the section designation by the

letter D. For example, a back to back double channel section

PFC140X60 without spacing in between should be specified as:


13-12

100 TO 150 TABLE D PFC140X60

A back to back double channel section 140X60X16C with spacing

0.01unitlength in between should be specified as:

100 TO 150 TABLE D 140X60X16C SP 0.01

Note that the specification SP after the section designation is used

for providing the spacing. The spacing should always be provided

in the current length unit.

Angles

To specify angles, the letter L succeeds the angle name. Thus, a

70X70 angle with a 25mm thickness is designated as 70X70X8L.

The following examples illustrate angle specifications.

100 TO 150 TABLE ST 70X70X8L

Note that the above specification is for “standard” angles. In this

specification, the local z-axis (see Fig. 2.6 in the Technical

Reference Manual) corresponds to the Y‟-Y‟ axis shown in the

CSA table. Another common practice of specifying angles assumes

the local y-axis to correspond to the Y‟-Y‟ axis. To specify angles

in accordance with this convention, the reverse angle designation

facility has been provided. A reverse angle may be specified by

substituting the word ST with the word RA. Refer to the following

example for details.

100 TO 150 TABLE RA 45X45X3L

The local axis systems for STANDARD and REVERSE angles are

shown in Fig. 2.6 of the STAAD Technical Reference manual.

Section 13B

13-13

Double Angles

To specify double angles, the specification ST should be

substituted with LD (for long leg back to back) or SD (short leg

back to back). For equal angles, either SD or LD will serve the

purpose. Spacing between angles may be provided by using the

word SP followed by the value of spacing (in current length unit)

after section designation.

100 TO 150 TABLE LD 50X50X3L 3 TABLE LD 40X40X5L SP 0.01

The second example above describes a double angle section

consisting of 40X40X5 angles with a spacing of 0.01 length units.

Tees

Tee sections obtained by cutting W sections may be specified by

using the T specification instead of ST before the name of the W

shape. For example:

100 TO 150 TABLE T IPE-AA180

will describe a T section cut from a IPE-AA180 section.

Rectangular Hollow Sections

These sections may be specified in two possible ways. Those

sections listed in the SAB tables may be specified as follows.

100 TO 150 TABLE ST TUB60X30X2.5


13-14

In addition, any tube section may be specified by using the DT(for

depth), WT(for width), and TH(for thickness) specifications. For

example:

100 TO 150 TABLE ST TUBE TH 3 WT 100 DT 50

will describe a tube with a depth of 50mm, width of 100mm. and a

wall thickness of 3mm. Note that the values of depth, width and

thickness must be provided in current length unit.

Circular Hollow Sections

Sections listed in the SAB tables may be provided as follows:

100 TO 150 TABLE ST PIP34X3.0CHS

In addition to sections listed in the SAB tables, circular hollow

sections may be specified by using the OD (outside diameter) and

ID (inside diameter) specifications.

Pipe symbol

Thickness

PIP34X3.0

Diameter

Width

Tube symbol

Height

Thickness

TUB60X30X2.5

Section 13B

13-15

For example:

100 TO 150 TABLE ST PIPE OD 50 ID 48

will describe a pipe with an outside diameter of 50 length units

and inside diameter of 48 length units. Note that the values of

outside and inside diameters must be provided in terms of current

length unit.

Sample input file to demonstrate usage of South African shapes is

shown below.

STAAD PLANE START JOB INFORMATION ENGINEER DATE 30-Mar-05 END JOB INFORMATION UNIT METER KN JOINT COORDINATES 1 0 0 0; 2 9 0 0; 3 0 6 0; 4 3 6 0; 5 6 6 0; 6 9 6 0; 7 0 10.5 0; 8 9 10.5 0; 9 2.25 10.5 0; 10 6.75 10.5 0; 11 4.5 10.5 0; 12 1.5 11.4 0; 13 7.5 11.4 0; 14 3 12.3 0; 15 6 12.3 0; 16 4.5 13.2 0; MEMBER INCIDENCES 1 1 3; 2 3 7; 3 2 6; 4 6 8; 5 3 4; 6 4 5; 7 5 6; 8 7 12; 9 12 14; 10 14 16; 11 15 16; 12 13 15; 13 8 13; 14 9 12; 15 9 14; 16 11 14; 17 11 15; 18 10 15; 19 10 13; 20 7 9; 21 9 11; 22 10 11; 23 8 10; MEMBER PROPERTY SAFRICAN 1 TABLE ST IPE-AA100 2 TABLE T IPE120 3 TABLE ST 152X23UC 4 TABLE T 152X23UC 5 TABLE ST 812X200PG 6 TABLE T 812X200PG 7 TABLE ST 178X54X15C 8 TABLE D 178X54X15C 9 TABLE D 178X54X15C SP 0.1 10 TABLE ST 25X25X5L 11 TABLE RA 25X25X5L 12 TABLE LD 25X25X5L 13 TABLE SD 25X25X5L 14 TABLE LD 25X25X5L SP 0.1 15 TABLE SD 25X25X5L SP 0.1


13-16

16 TABLE ST TUB40X2.5SHS 17 TABLE ST TUBE TH 0 WT 0 DT 50 18 TABLE ST TUBE TH 0.02 WT 100 DT 50 20 TABLE ST PIP48X2.0CHS 21 TABLE ST PIPE OD 0.5 ID 0.48 PRINT MEMBER PROPERTIES FINISH


The SAB specification allows inelastic deformation of section


Steel sections are classified as plastic (Class 1), compact (Class 2),

non compact (Class 3) or slender element (Class 4) sections

depending upon their local buckling characteristics (See Clause

11.2 and Table 1 of SAB0162-1:1993). This classification is a


procedures are different depending on the section class. STAAD

determines the section classification for the standard shapes and

user specified shapes. Design is performed for sections that fall

into the category of Class 1,2 or 3 sections only. Class 4 sections

are not designed by STAAD.



procedures outlined in section 13 of the specification. These

depend on several factors such as members‟ unsupported lengths,

cross-sectional properties, slenderness factors, unsupported width

to thickness ratios and so on. Note that the program automatically

takes into consideration appropriate resistance factors to calculate

member resistances. Explained here is the procedure adopted in

STAAD for calculating the member resistances.

All the members are checked against allowable slenderness ratio as

per Cl.10.2 of SAB0162-1: 1993.

Section 13B

13-17

Axial Tension

The criterion governing the capacity of tension members is based

on two limit states. The limit state of yielding in the gross section

is intended to prevent excessive elongation of the member. The



by the user through the use of the parameter NSF (see Table 3B.1).


these two limits states per Cl.13.2 of SAB0162-1: 1993.

Parameters FYLD, FU and NSF are applicable for these

calculations.

Axial Compression


Clause 13.3 of the code. The equations presented in this section of

the code assume that the compressive resistance is a function of

the compressive strength of the gross section (Gross section Area

times the Yield Strength) as well as the slenderness factor (KL/r

ratios). The effective length for the calculation of compression

resistance may be provided through the use of the parameters KX,

KY, KZ, LX, LY and LZ (see Table 3B.1). Some of the aspects of

the axial compression capacity calculations are:

1. For frame members not subjected to any bending, and for truss

members, the axial compression capacity in general column

flexural buckling is calculated from Cl.13.3.1 using the

slenderness ratios for the local Y-Y and Z-Z axis. The


2. For single angles, asymmetric or cruciform sections are

checked as to whether torsional-flexural buckling is critical.

But for KL/r ratio exceeding 50,as torsional flexural buckling

is not critical, the axial compression capacities are calculated

by using Cl.13.3. The reason for this is that the South African

code doesn‟t provide any clear guidelines for calculating this

value. The parameters KY, LY, KZ and LZ are applicable for

this.


13-18

3. The axial compression capacity is also calculated by taking

flexural-torsional buckling into account. Parameters KX and

LX may be used to provide the effective length factor and

effective length value for flexural-torsional buckling. Flexural-

torsional buckling capacity is computed for single channels,

single angles, Tees and Double angles.

4. While computing the general column flexural buckling

capacity of sections with axial compression + bending, the

special provisions of 13.8.1(a), 13.8.1(b) and 13.8.1(c) are

applied. For example, Lambda = 0 for 13.8.1(a), K=1 for

13.8.1(b), etc.)

Bending

The laterally unsupported length of the compression flange for the

purpose of computing the factored moment resistance is specified

in STAAD with the help of the parameter UNL. If UNL is less

than one tenth the member length (member length is the distance

between the joints of the member), the member is treated as being

continuously laterally supported. In this case, the moment

resistance is computed from Clause 13.5 of the code. If UNL is

greater than or equal to one-tenth the member length, its value is

used as the laterally unsupported length. The equations of Clause

13.6 of the code are used to arrive at the momen t of resistance of

laterally unsupported members. Some of the aspects of the bending

capacity calculations are:

1. The weak axis bending capacity of all sections except single

angles is calculated as

For Class 1 & 2 sections, Phi*Py*Fy

For Class 3 sections, Phi*Sy*Fy

Where Phi = Resistance factor = 0.9

Py = Plastic section modulus about the local Y axis

Sy = Elastic section modulus about the local Y axis

Fy = Yield stress of steel

Section 13B

13-19

2. For single angles sections are not designed by STAAD, as the

South African code doesn‟t provide any clear guidelines for

calculating this value.

3. For calculating the bending capacity about the Z-Z axis of

singly symmetric shapes such as Tees and Double angles,

SAB0162-1: 1993 stipulates in Clause 13.6(b), page 31, that a

rational method.




interaction equations. In these equations, the additional bending

caused by the action of the axial load is accounted for by using

amplification factors. Clause 13.8 of the code provides the

equations for this purpose. If the summation of the left hand side

of these equations exceeds 1.0 or the allowable value provided

using the RATIO parameter (see Table 3B.1), the member is

considered to have FAILed under the loading condition.


Members subjected to axial tension and bending are also designed

using interaction equations. Clause 13.9 of the code is used to

perform these checks. The actual RATIO is determined as the

value of the left hand side of the critical equation.

Shear


equations of Clause 13.4 of the code. Once this is obtained, the

ratio of the shear force acting on the cross section to the shear

resistance of the section is calculated. If any of the ratios (for both

local Y & Z axes) exceed 1.0 or the allowable value provided

using the RATIO parameter (see Table 3B.1), the section is

considered to have failed under shear. The code also requires that

the slenderness ratio of the web be within a certain limit (See

Cl.13.4.1.3, page 29 of SABS 0162-1:1993). Checks for safety in

shear are performed only if this value is within the allowable limit.


13-20

Users may by-pass this limitation by specifying a value of 2.0 for

the MAIN parameter.


The design parameters outlined in table below may be used to




specific needs.








South African steel design parameters

Parameter

Name


Kt 1.0 K value for flexural torsional buckling

Ky 1.0 K value in local Y-axis, usually minor axis

Kz 1.0 K value in local Z-axis, usually major axis

Lt Member length Length for flexural torsional buckling

Ly Member length Length in local Y axis for slenderness

value KL/r

Lz Member length Length in local Z axis for slenderness value

KL/r

Fyld 300Mpa Yield strength of steel

Fu 345Mpa Ultimate strength of steel

NSF 1.0 Net section factor for tension members

Section 13B

13-21


Parameter

Name


UNT Member Length

Unsupported length in bending

compression of top flange for calculating

moment resistance

UNB Member Length

Unsupported length in bending

compression of bottom flange for

calculating moment resistance

Main 0

Flag for controlling slenderness check

0 - For Check for slenderness.

1 - For Do not check for slenderness

Cb 1.0

Greater than 0.0 and less than 2.5,Value of

Omega_2 (C1.13.6) to be used for

calculation

Equal to 0.0: Calculate Omega_2

Ssy 0

Sidesway parameter

0 - Sideway about local Y-axis.

1 - No sideway about local Y-axis.

Ssz 0

Sidesway parameter

0 - Sideway about local Z-axis.

1 - No sideway about local Z-axis.

Cmy 1.0

1 - Do not calculate Omega-1 for local Y

axis.

2 - Calculate Omega-1 for local Y axis

Cmz 1.0

1 - Do not calculate Omega-1 for local Z

axis.

2 - Calculate Omega-1 for local Z axis

Track 0

Track parameter

0 = Print the design output at the minimum

detail level.

1 = Print the design output at the


13-22


Parameter

Name


intermediate detail level.

2 = Print the design output at maximum

detail level

Dmax 1000 Maximum allowable depth

Dmin 0 Minimum required depth

Ratio 1.0

Permissible ratio of applied load to section

capacity

Used in altering the RHS of critical

interaction equations

Beam 0

0 - Perform design at ends and those

locations specified in the section command.

1 - Perform design at ends and 1/12th

section locations along member length.

Dff 0 Default is 0 indicating that deflection

check is not performed

Dj1 0

Start node of physical member for

determining deflected pattern for deflection

check and should be set along with DFF

parameter

Dj2 0

End node of physical member for

determining deflected pattern for deflection

check and should be set along with DFF

parameter

13B.8 Code Checking

The purpose of code checking is to determine whether the current


obtained from the most recent analysis. The adequacy is checked

as per the SAB0162-1: 1993 requirements.

Section 13B

13-23



set to 1 (which is also its default value), moments are calculated at

every twelfth point along the beam. When no section locations are

specified and the BEAM parameter is set to zero, design will be

based on member start and end forces only. The code checking

output labels the members as PASSed or FAILed. In addition, the

critical condition, governing load case, location (di stance from the

start joint) and magnitudes of the governing forces and moments

are also printed. Using the TRACK parameter can control the

extent of detail of the output.

PARAMETER CODE SAB0162 MAIN 1 all LY 4 MEMB 1 LZ 4 MEMB 1 UNL 4 MEMB 1 CB 0 MEMB 1 TO 23 CMZ MEMB 2 1 TO 23 CMY MEMB 2 1 TO 23 SSY 0 MEMB 1 TO 23 SSZ 0 MEMB 1 TO 23 FU 450000 MEMB 1 TO 23 BEAM 1 ALL NSF 0.85 ALL KY 1.2 MEMB 3 4 RATIO 1.0 ALL TRACK 2 ALL FYLD 300000 1 TO 23 CHECK CODE ALL FINISH


13-24


The member selection process involves determination of the least

weight member that PASSes the code checking procedure based on

the forces and moments of the most recent analysis. The section

selected will be of the same type as that specified initially. For

example, a member specified initially as a channel will have a



the user table. Member selection cannot be performed on members

listed as PRISMATIC.




the SAB0162-1: 1993 specification, which governed the design.

If the TRACK parameter is set to 1.0, the output will be displayed

as follows:

**************************************

STAAD.PRO CODE CHECKING

(SOUTHAFRICAN STEEL/SAB-0162-01(1993))

**************************************



FX MY MZ LOCATION

=======================================================================

* 1 ST PFC140X60 (SOUTHAFRICAN SECTIONS)

FAIL SAB-13.9 4.321 1

-20.00 0.00 82.53 0.00

|---------------------------------------------------------------------|

| FACTORED RESISTANCES FOR MEMBER- 1 UNIT - KN,M PHI = 0.90 |

| MRZ= 14.35 MRY= 3.86 |

| CR= 58.41 TR= 425.81 VR= 123.85 |

|---------------------------------------------------------------------|

Factored member resistances will be printed out. Following is a

description of some of the items printed out.

MRZ= Factored moment of resistance in z direction

Section 13B

13-25

MRY= Factored moment of resistance in z direction

CR = Factored compressive resistance for column

TR= Factored tensile capacity

VR= Factored shear resistance

Further details can be obtained by setting TRACK to 2.0. A typical

output of track 2.0 parameter is as follows.

**************************************



**************************************



FX MY MZ LOCATION

=======================================================================

* 1 ST PFC140X60 (SOUTHAFRICAN SECTIONS)

FAIL SAB-13.9 4.321 1

-20.00 0.00 82.53 0.00


-----------------------------


IZ = 6.05E+02 SZ = 8.64E+01 PZ = 4.24E+02

IY = 6.91E+01 SY = 1.73E+01 PY = 1.52E+02


--------------------------------

FYLD = 248.2 FU = 285.4


---------------------------------

CRY = 5.841E+01 CRZ = 2.947E+02

CTORFLX = 2.021E+02





--------------------------








13-26

Following is a description of some of the items printed out.

CRY Factored compressive resistance for column buckling

about the local y axis

CRZ Factored compressive resistance for column buckling

about the local z axis

CTORFLX Factored compressive resistance against torsional

flexural buckling

TENSILE

CAPACITY

Factored tensile capacity

COMPRESSIVE

CAPACITY

Factored compressive capacity

FACTORED MOMENT

RESISTANCE

MRY = Factored moment of resistance in y direction

MRZ = Factored moment of resistance in z direction

FACTORED SHEAR

RESISTANCE

VRY = Factored shear resistance in y direction

VRZ = Factored shear resistance in z direction

13B.11 Verification Problems


reference purposes.

Section 13B

13-27


Objective: - To determine the capacity of a South African I-

section column in axial compression. Column is

braced at its ends for both axes.

Design Code: - South African steel design code (SAB:0162-

1(1993))

Reference: - Example 4.3.4.1, page 4.18, Structural Steel

Design to SAB:0162-1(1993)(Limit state Design)

by Greg Parrott, 1st edition, Shades Technical

publication

Given: - FYLD = 300Mpa

Length = 6000mm

Comparison: -


Theory 1516

STAAD 1516

Difference No


13-28

****************************************************

* *

* STAAD.Pro *

* Version Bld *



* Date= *

* Time= *

* *

* USER ID: *

****************************************************

1. STAAD PLANE

2. START JOB INFORMATION

3. ENGINEER DATE

4. END JOB INFORMATION

5. INPUT WIDTH 79

6. ***********************************************

7. * STAAD.PRO GENERATED COMMENT *

8. ***********************************************

9. *1 0 0 0,2 0 6 0

10. ***********************************************

11. UNIT METER KN


13. 1 0 0 0; 2 0 6 0


15. 1 1 2

16. MEMBER PROPERTY SAFRICAN

17. 1 TABLE ST 356X67UB

18. DEFINE MATERIAL START

19. ISOTROPIC MATERIAL1

20. E 2.0E+008

21. POISSON 0.3

22. DENSITY 76.977

23. ISOTROPIC STEEL

24. E 2.00E+008

25. POISSON 0.3

26. DENSITY 76.8195

27. ALPHA 1.2E-005

28. DAMP 0.03

29. END DEFINE MATERIAL

30. UNIT MMS KN

31. CONSTANTS

32. MATERIAL STEEL MEMB 1

33. UNIT METER KN

34. SUPPORTS

35. 1 FIXED

36. LOAD 1 LOADTYPE NONE TITLE LOAD CASE 1

37. JOINT LOAD

38. 2 FY -1500



-----------------------------------






40. PARAMETER

41. CODE SAB0162

42. LZ 6 ALL

43. LY 3 ALL

44. FU 450000 ALL

45. BEAM 1 ALL

46. NSF 0.85 ALL

47. TRACK 2 ALL

48. FYLD 300000 ALL

49. CHECK CODE ALL

Section 13B

13-29

**************************************



**************************************



FX MY MZ LOCATION

=======================================================================

1 ST 356X67UB (SOUTHAFRICAN SECTIONS)

PASS SAB-13.8 0.989 1

1500.00 0.00 0.00 0.00


-----------------------------


IZ = 1.95E+04 SZ = 1.07E+03 PZ = 1.21E+03

IY = 1.36E+03 SY = 1.57E+02 PY = 2.43E+02


--------------------------------

FYLD = 300.0 FU = 345.0


---------------------------------

CRY = 1.516E+03 CRZ = 2.038E+03

CTORFLX = 1.516E+03





--------------------------







50. FINISH


13-30


Objective:- To determine the capacity of a South African I-section

beam in bending. The beam has torsional and simple

lateral rotational restraint at the supports, and the

applied point load provides effective lateral restraint at

the point of application is braced at its ends for both

axes.

Design Code: - South African steel design code (SAB:0162-

1(1993))

Reference: - Example 4.5, page 4.37, Structural Steel Design to

SAB:0162-1(1993)(Limit state Design) by Greg Parrott,

1st edition, Shades Technical publication


Comparison: -

Solution Design Strength (kN-m)

Theory 353.4

STAAD 353.3

Difference Small

Section 13B

13-31

****************************************************

* *

* STAAD.Pro *

* Version Bld *



* Date= *

* Time= *

* *

* USER ID: *

****************************************************

1. STAAD PLANE


3. ENGINEER DATE


5. INPUT WIDTH 79

6. UNIT METER KN


8. 1 0 0 0; 2 10 0 0; 3 7 0 0


10. 1 1 3; 2 3 2


12. 1 2 TABLE ST 406X67UB



15. E 2.0E+008

16. POISSON 0.3

17. DENSITY 76.977

18. ISOTROPIC STEEL

19. E 2.00E+008

20. POISSON 0.3

21. DENSITY 76.8195

22. ALPHA 1.2E-005

23. DAMP 0.03


25. UNIT MMS KN

26. CONSTANTS

27. MATERIAL STEEL MEMB 1 2

28. UNIT METER KN

29. SUPPORTS

30. 1 3 PINNED


32. MEMBER LOAD

33. 1 CON GY -104 4

34. 1 UNI GY -26.4

35. 2 UNI GY -7.2



-----------------------------------






37. PARAMETER

38. CODE SABS0162

39. CB 0 ALL

40. UNL 4 MEMB 1

41. FU 450000 ALL

42. BEAM 1 ALL

43. NSF 0.85 ALL

44. FYLD 300000 ALL

45. TRACK 2 ALL

46. CHECK CODE MEMB 1


13-32

**************************************



**************************************



FX MY MZ LOCATION

=======================================================================

1 ST 406X67UB (SOUTHAFRICAN SECTIONS)

PASS SHEAR 0.244 1

0.00 0.00 32.40 7.00


-----------------------------


IZ = 2.43E+04 SZ = 1.19E+03 PZ = 1.35E+03

IY = 1.36E+03 SY = 1.52E+02 PY = 2.37E+02


--------------------------------

FYLD = 300.0 FU = 345.0


---------------------------------

CRY = 4.532E+02 CRZ = 2.016E+03

CTORFLX = 4.532E+02





--------------------------





SHEAR FORCE (KNS) : Y AXIS = 0.000E+00 Z AXIS = -1.565E+02


47. FINISH

Section 13B

13-33


Objective: - To determine the elastic shear capacity of a South

African I-section which is simply supported over the

span of 8 m

Design Code: - South African steel design code (SAB:0162-1(1993))

Reference: - Example 4.6.5, page 4.54, Structural Steel Design to

SAB:0162-1(1993)(Limit state Design) by Greg Parrott,

1st edition, Shades Technical publication


Comparison: -


Theory 687.1

STAAD 687.1

Difference No


13-34

****************************************************

* *

* STAAD.Pro *

* Version Bld *



* Date= *

* Time= *

* *

* USER ID: *

****************************************************

1. STAAD PLANE


3. ENGINEER DATE


5. INPUT WIDTH 79

6. UNIT METER KN


8. 1 0 0 0; 2 8 0 0


10. 1 1 2


12. 1 TABLE ST 457X67UB



15. E 2E+008

16. POISSON 0.3

17. DENSITY 76.977

18. ISOTROPIC STEEL

19. E 2E+008

20. POISSON 0.3

21. DENSITY 76.8195

22. ALPHA 1.2E-005

23. DAMP 0.03


25. UNIT MMS KN

26. CONSTANTS

27. MATERIAL STEEL MEMB 1

28. UNIT METER KN

29. SUPPORTS

30. 1 2 PINNED


32. MEMBER LOAD

33. 1 UNI GY -70



-----------------------------------






35. PARAMETER

36. CODE SABS0162

37. FU 450000 ALL

38. BEAM 1 ALL

39. FYLD 300000 ALL

40. TRACK 2 ALL

41. CHECK CODE ALL

Section 13B

13-35

**************************************



**************************************



FX MY MZ LOCATION

=======================================================================

* 1 ST 457X67UB (SOUTHAFRICAN SECTIONS)

FAIL CLASS 4 SECT 2.000

0.00 0.00 0.00


-----------------------------


IZ = 2.94E+04 SZ = 1.30E+03 PZ = 1.47E+03

IY = 1.45E+03 SY = 1.53E+02 PY = 2.37E+02


--------------------------------

FYLD = 300.0 FU = 345.0


---------------------------------

CRY = 0.000E+00 CRZ = 0.000E+00

CTORFLX = 0.000E+00





--------------------------







42. FINISH


13-36

Section 14

American Aluminum Code

14-1

Design Per American Aluminum Code

14.1 General

STAAD is currently equipped with the facilities to perform design

based on the specifications for Aluminum Structures. The

requirements of the Allowable Stress Design, Sixth edition,

October 1994, have been implemented.

The various issues related to the implementation of this code in

STAAD are explained below.

14.2 Member Properties

In order to do this design in STAAD, the members in the structure

must have their properties specified from Section VI of the above-

mentioned manual. The section names are mentioned in Tables 5

through 28 of that manual. All of those tables except Table 10

(Wing Channels) and Table 20 (Bulb Angles) are available in

STAAD.

Described below is the command specification for various

sections:

Standard single section

memb-list TA ST section-name

Section 14


Section 14

14-2

Example

1 TO 5 TA ST CS12X11.8

9 TA ST I8.00X13.1

11 33 45 67 TA ST LS8.00X8.00X0.625

18 TA ST 1.50PipeX160

15 TA ST T(A-N)6.00X8.00X11.2

23 25 29 TA ST 20X12RectX.500Wall

Double channel back-to-back

memb-list TA BACK section-name SPACING value

Example

3 TA BACK C(A-N)7X3.61 SPACING 1.5

5 TA BACK C15X17.33 SP 0.75

Double channel front-to-front

memb-list TA FRONT section-name SPACING value

Example

2 TA FRONT CS12X10.3 SP 1.0

4 TA FR CS10X10.1 SP 0.5

Section 14

14-3

Double angle long leg back-to-back

memb-list TA LD section-name SPACING value

Example

14 TA LD LS4.00X3.00X0.375 SP 1.5

Double angle short leg back-to-back

memb-list TA SD section-name SPACING value

Example

12 TA SD L3.5X3X0.5 SP 0.25

13 TA SD L8X6X0.75 SP 1.0

14.3 Design Procedure

The design is done according to the rules specified in Sections 4.1,

4.2 and 4.4 on pages I-A-41 and I-A-42 of the Aluminum code.

The allowable stresses for the various sections are computed

according to the equations shown in Section 3.4.1 through 3.4.21

on pages I-A-27 through I-A-40. The adequacy of the member is

checked by calculating the value of the left -hand side of equations

4.1.1-1, 4.1.1-2, 4.1.1-3, 4.1.2-1, 4.4-1 and 4.4-2. This left-hand

side value is termed as RATIO. If the highest RATIO among these

equations turns out to be less than or equal to 1.0, the member is

declared as having PASSed. If it exceeds 1.0, the member has

FAILed the design requirements.


Section 14

14-4

The check for torsion per Clause 4.3 for open sections is currently

not done.

14.4 Design Parameters

The following are the parameters for specifying the values for

variables associated with the design. Note: Once a parameter is



Table 14.1 Aluminum Design Parameters


Name Value

ALLOY 34 This variable can take on a value from 1 through 40. The default value represents the alloy 6061-T6. See Table 12A.2 in the following pages for a list of values for this parameter and the alloy they represent. Table 3.3-1 in Section I-B of the Aluminum specifications provides information on the properties of the various alloys.

PRODUCT 1 This variable can take on a value from 1 through 4. They represent: 1 - All 2 - Extrusions 3 - Drawn Tube 4 - Pipe The default value stands for All. The PRODUCT parameter finds mention in Table 3.3-1 in Section I-B of the Aluminum specifications.

ALCLAD 0 This variable can take on a value of either 0 or 1. 0 - Material used in the section is not an Alclad. 1 - Material used in the section is an Alclad.

Section 14

14-5



Name Value

WELD 0 In Table 3.4-2 in Section I-A of the Aluminum specifications, it is mentioned that the value of coefficients Kt and Kc are dependent upon whether or not, the location of the section where design is done is within 1.0 inch of a weld. The WELD parameter is used in STAAD for this purpose. The values that can be assigned to this parameter are: 0 - Region is farther than 1.0in from a weld 1 - Region is within 1.0in from a weld

STRUCTURE 1 In Table 3.4-1 in Section I-A of the Aluminum specifications, it is mentioned that the value of coefficients nu, ny and na are dependent upon whether the structure being designed is a building or a bridge. Users may convey this information to STAAD using the parameter STRUCTURE. The values that can be assigned to this parameter are: 1 - Buildings and similar type structures 2 - Bridges and similar type structures

DMAX 1000 in. Maximum depth permissible for the section during member selection. This value must be provided in the current units.

DMIN 0.0 in Minimum depth required for the section during member selection. This value must be provided in the current units.

UNL Member length

Distance between points where the compression flange is braced against buckling or twisting. This value must be provided in the current units. This value is used to compute the allowable stress in bending compression.

KY 1.0 Effective length factor for overall column buckling in the local Y-axis. It is a fraction and is unit-less. Values can range from 0.01 (for a column completely prevented from buckling) to any user specified large value. It is used to compute the KL/R ratio for determining the allowable stress in axial compression.


Section 14

14-6



Name Value

LY Member length

Effective length for overall column buckling in the local Y-axis. It is input in the current units of length. Values can range from 0.01 (for a column completely prevented from buckling) to any user specified large value. It is used to compute the KL/R ratio for determining the allowable stress in axial compression.

KZ 1.0 Effective length factor for overall column buckling in the local Z-axis. It is a fraction and is unit-less. Values can range from 0.01 (for a column completely prevented from buckling) to any user specified large value. It is used to compute the KL/R ratio for determining the allowable stress in axial compression.

LZ Member length

Effective length for overall column buckling in the local Z-axis. It is input in the current units of length. Values can range from 0.01 (for a column completely prevented from buckling) to any user specified large value. It is used to compute the KL/R ratio for determining the allowable stress in axial compression.

KT 1.0 Effective length factor for torsional buckling. It is a fraction and is unit-less. Values can range from 0.01 (for a column completely prevented from torsional buckling) to any user specified large value. It is used to compute the KL/R ratio for twisting for determining the allowable stress in axial compression. See Equation 3.4.7.2-6 on page I-A-28 of the Aluminum specifications for details.

LT Member length

Unbraced length for twisting. It is input in the current units of length. Values can range from 0.01 (for a column completely prevented from torsional buckling) to any user specified large value. It is used to compute the KL/R ratio for twisting for determining the allowable stress in axial compression. See Equation 3.4.7.2-6 on page I-A-28 of the Aluminum specifications for details.

STIFF Member length

Spacing in the longitudinal direction of shear stiffeners for stiffened flat webs. It is input in the current units of length. See section 3.4.21 on page I-A-40 of the Aluminum specifications for information regarding this parameter.

Section 14

14-7



Name Value

SSY 0.0 Factor that indicates whether or not the structure is subjected to sidesway along the local Y axis of the member. The values are: 0 - Sidesway is present along the local Y-axis of the member 1 - There is no sidesway along the local Y-axis of the member. The sidesway condition is used to determine the value of Cm explained in Section 4.1.1, page I-A-41 of the Aluminum specifications.

SSZ 0.0 Factor that indicates whether or not the structure is subjected to sidesway along the local Z axis of the member. The values are: 0 - Sidesway is present along the local Z-axis of the member 1 - There is no sidesway along the local Z-axis of the member. The sidesway condition is used to determine the value of Cm explained in Section 4.1.1, page I-A-41 of the Aluminum specifications.

TRACK 2 This parameter is used to control the level of detail in which the design output is reported in the output file. The allowable values are: 1 - Prints only the member number, section name,

ratio, and PASS/FAIL status. 2 - Prints the design summary in addition to that

printed by TRACK 1 3 - Prints the member properties and alloy properties in addition to that printed by TRACK 2. 4 - Prints the values of variables used in design in

addition to that printed by TRACK 3.


Section 14

14-8



Name Value

BEAM 0.0 If this parameter is set to 1.0, the adequacy of the member is determined by checking a total of 13 equally spaced locations along the length of the member. If the BEAM value is 0.0, the 13 location check is not conducted, and instead, checking is done only at the locations specified by the SECTION command (See STAAD manual for details). If neither the BEAM parameter nor any SECTION command is specified, STAAD will terminate the run and ask the user to provide one of those 2 commands. This rule is not enforced for TRUSS members.

14.5 Code Checking

The purpose of code checking is to determine whether the initially

specified member properties are adequate to carry the forces

transmitted to the member due to the loads on the structure. Code

checking is done at the locations specified by either the SECTION

command or the BEAM parameter described above.

It is done with the aid of the command “CHECK CODE”

described in the main STAAD Technical Reference Manual.

Example Problem 1 in the Getting Started and Examples Manual

for STAAD provides an example on the usage of the CHECK

CODE command.

14.6 Member Selection

The member selection process involves the determination of the

least weight member that PASSes the code checking procedure




channel selected for it. It is done with the aid of the command

“SELECT MEMBER” described in the main STAAD Technical

Section 14

14-9

Reference Manual. Example Problem 1 in the Getting Started and

Examples Manual for STAAD provides an example on the usage of

the SELECT MEMBER command.

Sample input data for Aluminum Design

PARAMETER

CODE ALUMIMUM

BEAM 1 ALL

KY 1.2 MEMB 3 4

ALLOY 35 ALL

PRODUCT 2 ALL

TRACK 3 ALL

SELECT ALL

ALCLAD 1 ALL

STRUCT 1 ALL

CHECK CODE ALL


Section 14

14-10

Table 14.2 - ALLOY PARAMETER :

Values and Corresponding Names

1 1100-H12

2 1100-H14

3 2014-T6

4 2014-T6510

5 2014-T6511

6 2014-T651

7 3003-H12

8 3003-H14

9 3003-H16

10 3003-H18

11 3004-H32

12 3004-H34

13 3004-H36

14 3004-H38

15 5005-H12

16 5005-H14

17 5005-H32

18 5005-H34

19 5050-H32

20 5050-H34

21 5052-H32

22 5052-H34

23 5083-H111

24 5086-H111

25 5086-H116

26 5086-H32

27 5086-H34

28 5454-H111

29 5454-H112

30 5456-H111

31 5456-H112

32 6005-T5

33 6105-T5

Section 14

14-11

34 6061-T6

35 6061-T6510

36 6061-T6511

37 6061-T651

38 6063-T5

39 6063-T6

40 6351-T5


Section 14

14-12

Section 15

American Transmission Tower Code

15-1

Steel Design per ASCE 10-97

15A.1 General Comments


specifications of ASCE Standard 10-97 – Design of Latticed Steel

Transmission Structures is now implemented. This code is meant

to supercede the older edition of the code, available under the

name ASCE Publication 52. However, in the interests of backward

compatibility, both codes are currently accessible in STAAD.Pro.

To access the ASCE 52 code, use the commands

PARAMETER CODE ASCE 52

To access the ASCE 10-97 code, use the commands

PARAMETER CODE ASCE

In general, the concepts followed in MEMBER SELECTION and

CODE CHECKING procedures are similar to that of the AISC

based design. It is assumed that the user is familiar with the basic

concepts of steel design facilities available in STAAD. Please

refer to Section 2 of the STAAD Technical Reference Manual for

detailed information on this topic. This section specifically

addresses the implementation of steel design based on ASCE 10-

97.

Design is available for all standard sections listed in the AISC

ASD 9th

edition manual, namely, Wide Flanges, S, M, HP, Tees,

Channels, Single Angles, Double Angles, Tubes and Pipes. Design

Section 15A

Steel Design Per ASCE 10-97

Section 15A

15-2

of HSS sections (those listed in the 3 rd edition AISC LRFD

manual) and Composite beams (I shapes with concrete slab on top)

is not suppported.

15A.2 Allowable Stresses per ASCE 10 - 97

Member selection and code checking operations in th e STAAD

implementation of ASCE 10-97 are done to resist loads at stresses

approaching yielding, buckling, fracture and other limiting

conditions specified in the standard. Those stresses are referred to

in the standard as Design Stresses. The appropriate sections of the

ASCE standard where the procedure for calculating the design

stresses is explained are as follows.

Design Axial Tensile Stress

Design tensile stresses are calculated on the basis of the procedure

described in section 3.10. The NSF parameter (see the Parameters

table shown later in this section) may be used if the section area

needs to be reduced to account for bolt holes.

Design Axial Compressive Stress

Design compressive stress calculation is based on the procedures

of section 3.6 through 3.9. For angle members under compression,

the procedures of sections 3.7 and 3.8 have been implemented.

Capacity of the section is computed for column buckling and

wherever applicable, torsional buckling. The user may control the

effective lengths for buckling using the LT, LY, LZ and/or KT,

KY, KZ parameters (see the Parameters table shown later in this

section).

Design Bending Compressive Stress

Calculations for design bending compressive stress about the

major axis and minor axis are based on the procedures of section

3.14. Procedures outlined in sections 3.14.1 through 3.14.6 have

been implemented.

Section 15A

15-3

Design Bending Tensile Stress

Calculations for design bending tensile stress about the major and

minor axis are based on the procedures of section 3.14.2.

Design Shear Stress

Calculation of the design shear stress is based on the procedure

outlined in section 3.15 of the ASCE 10-97. The procedure of

section 3.15.2 is followed for angles and the procedure of section

3.15.1 is followed for all other sect ions.

15A.3 Critical Conditions used as criteria to determine Pass/Fail status

These are Clause 3.4 for slenderness limits, Clause 3.12 for Axial

Compression and Bending, Clause 3.13 for Axial Tension and

Bending, Clause 3.9.2 for Maximum w/t ratios and Clause 3.15 for

Shear.


Design per ASCE (10-97) must be initiated by using the command

CODE ASCE. This command should be the first command after the

PARAMETER statement. Other applicable parameters are

summarized in the table shown later in this section. These

parameters may be used to control the design process to suit

specific modeling needs. The default parameter values have been


conventional design.

15A.5 Code Checking and Member Selection


the ASCE 10-97 implementation. For general information on these


Section 15A

15-4

options, refer to sections 2 and 5 of the STAAD Technical

Reference Manual.

Table of Steel Design Parameters for ASCE 10-97

Parameter Name

Default Value

Description

KY 1.0 Effective length factor (K) for compression buckling about the Y-axis (minor axis)

KZ 1.0 Effective length factor (K) for compression buckling about the Z-axis (major axis)

KT 1.0 Effective length coefficient for warping restraint (clause 3.14.4, pg 11)

LY Member Length

Length to calculate slenderness ratio for buckling about the Y-axis (minor axis)

LZ Member Length

Length to calculate slenderness ratio for buckling about the Z-axis (major axis)

LT Member Length

Effective length for warping.

FYLD 36.0 KSI Yield Strength of steel NSF 1.0 Net section factor for tension members UNL Member

Length Unsupported length of member for calculation of allowable bending stress

UNF 1.0 Same as UNL, but provided as a fraction of the member length

TRACK 0.0 0.0 = Suppresses printing of allowable stresses 1.0 = Prints all allowable stresses

DMAX 45.0 in. Maximum allowable depth for member selection DMIN 0.0 in. Minimum allowable depth for member selection RATIO 1.0 Permissible ratio that determines the cut off point for

pass/fail status. A value below this quantity indicates PASS while a value greater than this quantity indicates FAILURE.

BEAM 1.0 0.0 = Perform design at beam ends and section locations specified according to the SECTION command 1.0 = Perform design at the ends and eleven

intermediate sections of the beam

Section 15A

15-5


Parameter Name

Default Value

Description

MAIN 2 Parameter that indicates the member type for the purpose of calculating the KL/R ratio (SEE CLAUSE 3.4, PAGE 3, ASCE 10-97) = 10 : DO NOT PERFORM THE KL/R CHECK = 1 : LEG MEMBER KL/R <= 150 = 2 : COMPRESSION MEMBER KL/R <= 200 = 3 : TENSION MEMBER KL/R <= 500 = 4 : HANGAR MEMBERS KL/R <= 375 (Clause 4C.4, page 43) = 5 : REDUNDANT MEMBERS KL/R <= 250

ELA 4 Indicates what type of end conditions are to be used from among Equations 3.7-4 thru 3.7-7 to determine the KL/R ratio. ELA=1 : EQN.3.7-4, Page 4

(VALID FOR LEG MEMBERS ONLY) ELA=2 : EQN.3.7-5, Page 4 ELA=3 : EQN.3.7-6, Page 4 ELA=4 : EQN.3.7-7, Page 5

ELB 1 Indicates what type of end conditions are to be used from among Equations. 3.7-8 thru 3.7-10 and 3.7-12 thru 3.7-14 to determine the KL/R ratio. ELB=1 : EQN.3.7-8, Page 5, EQN.3.7-12, Page 5 ELB=2 : EQN.3.7-9, Page 5, EQN.3.7-13, Page 5 ELB=3 : EQN.3.7-10, Page 5, EQN.3.7-14,Page 5


Section 15A

15-6


Parameter Name

Default Value

Description

LEG 0.0 This parameter is meant for plain angles. 0.0 = indicates that the angle is connected by both legs and allowable stress in axial tension is 1.0FYLD. 1.0 = indicates that the angle is connected only by the shorter leg and allowable tensile stress is computed per clause 3.10.2 as 0.9FYLD. 2.0 = indicates that the angle is connected by the longer leg.

DBL 0.75 in. Diameter of bolt for calculation of number of bolts required and the net section factor.

FYB 36 KSI Yield strength of bolt. FVB 30 KSI Shear strength of bolt. NHL

0 Number of bolt holes on the cross section that should be used to determine the net section factor for tension capacity.

Notes:

All values must be provided in the current unit system.

Once a parameter is specified, its value stays at that specified number

till it is specified again. This is the way STAAD works for all codes.

15-7

Steel Design per ASCE Manuals and Reports


This document presents some general statements regarding the

implementation of the Steel Design per ASCE Manuals and

Reports on Engineering Practice No. 52 – Guide for Design of

Steel Transmission Towers, Second Edition. The design

philosophy and procedural logistics for member selection and code

checking is based upon the principles of allowable stress design.

Two major failure modes are recognized: failure by overstressing

and failure by stability considerations.

The following sections describe the salient features regarding the

process of calculation of the relevant allowable stresses and the

stability criteria being used. Members are proportioned to resist

the design loads without exceeding the allowable stresses and the

most economical section is selected based on the least weight


slenderness requirements, the minimum metal thickness

requirements and the width-thickness requirements. It is generally

assumed that the user will take care of the detailing requirements

like provision of stiffeners and check the local effects like flange

buckling, web crippling, etc. It general, it may be noted that the

concepts followed in MEMBER SELECTION and CODE

CHECKING procedures are similar to that of the AISC based

design. It is assumed that the user is familiar with the basic

concepts of Steel Design facilities available in STAAD. Please

refer to Section 3 of the STAAD Technical Reference Manual for

detailed information on this topic. This document specifically

addresses the implementation of steel design based on ASCE Pub.

52.

Section 15B

Steel Design Per ASCE Manuals and Reports

Section 15B

15-8

15B.2 Allowable Stresses per ASCE (Pub. 52)

The member design and code checking in the STAAD

implementation of ASCE (Pub. 52) is based upon the allowable

stress design method. Appropriate sections of this publication are

referenced below.

Allowable Axial Tensile Stress

Allowable tensile stresses are calculated on the basis of the

procedure described in section 4.10. The NSF parameter (Table

1.1) may be used if the net section area needs to be used.

Allowable Axial Compressive Stress

Allowable compressive stress calculation is based on the

procedures of section 4.6 through 4.9. For angle members under

compression, the procedures of sections 4.7 and 4.8 have been

implemented. Capacity of the section is computed for column

buckling and wherever applicable, torsional buckling. The user

may control the effective lengths for buckling using the LX, LY,

LZ and/or KX, KY, KZ parameters (Table 1.1).

Allowable Bending Compressive Stress

Calculations for allowable bending compressive stress about the

major axis and minor axis are based on the procedures of section

4.14. Procedures outlined in sections 4.14.1 through 4.14.6 have

been implemented.

Allowable Bending Tensile Stress

Calculations for allowable bending tensile stress about the major

and minor axis are based on the procedures of section 4.14.2.

Allowable Shear Stress

Calculation of the allowable shear stress is based on the procedure

outlined in section 4.15 of the ASCE Pub. 52. The procedure of

Section 15B

15-9

section 4.15.2 is followed for angles and the procedure of section

4.15.1 is followed for all other sections.

Critical Conditions used as criteria to determine Pass/Fail

status

These are Clause 4.4 for slenderness limits, Equation 4.12-1 for

Axial Compression and Bending, Equation 4.13-1 for Axial

Tension and Bending, Clause 4.9.2 for Maximum w/t ratios and

Clause 4.15 for Shear.


Design per ASCE (Pub. 52) must be initiated by using the

command CODE ASCE. This command should be the first

command after the PARAMETER statement. Other applicable

parameters are summarized in Table 1.1. These parameters may be

used to control the design process to suit specific modeling needs.


frequently used numbers for conventional design.



the ASCE Pub. 52 implementation. For general information on

these options, refer to section 3 of the STAAD Technical

Reference Manual. For information on specification of these

commands, refer to section 6.


Section 15B

15-10

15B.5 Parameter Definition Table

Table 15B.1 - Steel Design Parameters for ASCE (PUB. 52) Based Design

Parameter Name

Default Value

Description

KY 1.0 Effective length factor (K) for compression buckling about the Y-axis (minor axis)

KZ 1.0 Effective length factor (K) for compression buckling about the Z-axis (major axis)

KT 1.0 Effective length coefficient for warping restraint (clause 4.14.4, pg 36)

LY Member Length

Length to calculate slenderness ratio for buckling about the Y-axis (minor axis)

LZ Member Length

Length to calculate slenderness ratio for buckling about the Z-axis (major axis)

LT Member Length

Effective length for warping.

FYLD 36.0 KSI Yield Strength of steel NSF 1.0 Net section factor for tension members UNL Member

Length Unsupported length of member for calculation of allowable bending stress

UNF 1.0 Same as UNL, but provided as a fraction of the member length

TRACK 0.0 1.0 = Suppresses printing of allowable stresses 1.0 = Prints all allowable stresses

DMAX 45.0 in. Maximum allowable depth for member selection DMIN 0.0 in. Minimum allowable depth for member selection RATIO 1.0 Permissible ratio that determines the cut off point for

pass/fail status. A value below this quantity indicates PASS while a value greater than this quantity indicates FAILURE.

Section 15B

15-11


Parameter Name

Default Value

Description

BEAM 0.0 2.0 = Perform design using the section locations specified according to the SECTION command 3.0 = Perform design at the ends and eleven intermediate sections of the beam

MAIN 2 Parameter that indicates the member type for the purpose of calculating the KL/R ratio (SEE CLAUSE 4.4, PAGE 25) = 10 : DO NOT PERFORM THE KL/R CHECK = 1 : LEG MEMBER KL/R <= 150 = 2 : COMPRESSION MEMBER KL/R <= 200 = 3 : TENSION MEMBER KL/R <= 500 = 4 : HANGAR MEMBERS KL/R <= 375 (Clause 4C.4, page 43) = 5 : REDUNDANT MEMBERS KL/R <= 250

ELA 4 Indicates what type of end conditions are to be used From among Equations 4.7-4 thru 4.7-7 to determine the the KL/R ratio. ELA=1 : EQN.4.7-4, Page 26

(VALID FOR LEG MEMBERS ONLY) ELA=2 : EQN.4.7-5, Page 27 ELA=3 : EQN.4.7-6, Page 27 ELA=4 : EQN.4.7-7, Page 27

ELB 1 Indicates what type of end conditions are to be used From among Equations. 4.7-8 thru 4.7-10 to determine the KL/R ratio. ELB=1 : EQN.4.7-8, Page 27, EQN.4.7-12, Page 28 ELB=2 : EQN.4.7-9, Page 27, EQN.4.7-13, Page 28 ELB=3 : EQN.4.7-10, Page 27, EQN.4.7-14,Page28


Section 15B

15-12


Parameter Name

Default Value

Description

LEG 0.0 This parameter is meant for plain angles. 3.0 = indicates that the angle is connected by both legs and allowable stress in axial tension is 1.0FYLD. 4.0 = indicates that the angle is connected only by the shorter leg and allowable tensile stress is computed per clause 4.10.2 as 0.9FYLD. 5.0 = indicates that the angle is connected by the longer leg.

DBL 0.75 in. Diameter of bolt for calculation of number of bolts required and the net section factor.

FYB 36 KSI Yield strength of bolt. FVB 30 KSI Shear strength of bolt. NHL

0 Number of bolt holes on the cross section that should be used to determine the net section factor for tension capacity.

Notes:

All values must be provided in the current unit system.




Section 16

American Steel Design Per A.P.I. Code

16-1

Steel Design Per A.P.I.

16.1 Design Operations


structural members as individual components of an analyzed




requirements of the design problem. The operations to perform a

design are:


design;


selection;


values; and

Specify design parameters to carry out punching shear checks.


depending upon the design requirements, but care should be taken

when coupled with manipulation of the punching shear LEG

parameter.

The basic process is:-

a. Define the STAAD model geometry, loading and analysis.

b. Define the API code parameters with LEG 1.0.

c. Run the analysis and API design which creates the Geometry

file and give preliminary design results.

d. Check and modify the Geometry file as necessary.

Section 16


Section 16

16-2

e. Reset the LEG parameter to 2.0 and re-run the analysis to read

the modified Geometry file for the final design results.

16.2 Allowables per API Code

For steel design, STAAD compares the actual stresses with the

allowable stresses as defined by the American Petroleum Institute

(API-RP2A) Code. The 20th edition of API Code, as published in

1993, is used as the basis of this design (except for tension stress).

16.2.1 Tension Stress

Allowable tension stresses, as calculated in STAAD, are based on

the API Code, clause (3.2.1-1).

Allowable tension stress on the net section

Ft = 0.60Fy

16.2.2 Shear Stress

Beam Shear Stress

Allowable beam shear stress on the gross section must conform to

(3.2.4-2):

Fv = 0.4 Fy

The maximum applied beam shear stress is:

fv = V / 0.5 A (3.2.4-1)

Torsional Shear Stress

Allowable torsional shear stress

Fvt = 0.4 Fy (3.2.4-4)

Section 16

16-3

Fvt is the maximum torsional shear stress per (3.2.4-3).

16.3 Stress due to Compression

The allowable compressive stress on the gross section of axially

loaded compression members is calculated based on the formula

3.2.2-1 in the API Code, when the largest effective slenderness

ratio

r

Kl is less than Cc =

yF

E22 . If r

Kl exceeds Cc the

allowable compressive stress is increased as per formula (3.2.2 -2)

of the Code.

For t

D > 60 the lesser of Fxe or Fxc are substituted for Fxy .

Fxe = the elastic local buckling stress calculated with C, the critical

elastic buckling coefficient = 0.3 (3.2.2-3)

Fxc = the inelastic local buckling stress, (3.2.2-4)

16.4 Bending Stress

The allowable bending stress for tension and compression for a

symmetrical member loaded in the plane of its minor axis, as given

in Section 3.2.3 is:

a) Fb = 0.75 Fy

provided t

D

yF

1500 (Imperial Units)

b) Fb =

Et

DFy74.184.0 Fy


Section 16

16-4

where

yF

1500 <

t

D <

yF

3000 (Imperial Units)

c) Fb =

Et

DFy58.072.0 Fy

where

yF

3000 <

t

D 300 (Imperial Units)

16.5 Combined Compression and Bending

Members subjected to both axial compression and bending stresses

are proportioned to satisfy API formula 3.3.1-1 and 3.3.1-2 when

a

a

F

f is greater than 0.15, otherwise formula 3.3.1-3 applies. It

should be noted that during code checking or member selection, if

a

a

F

f exceeds unity, the program does not compute the second

3.3.1-1/2.

16.6 Design Parameters

The program contains a large number of parameter names which

are required to perform design and code checks. These parameter

names, with their default values, are listed in Table 12.1. These

parameters communicate design decisions from the engineer to the

program. (Also see section 5.44.1).



the particular design requirements for an analysis, some or all of

these parameter values may have to be changed to exactly model

the physical structure. For example, by default the KZ value (k

value in local z-axis) of a member is set to 1.0, wile in the real

Section 16

16-5

structure it may be 1.5. In that case, the KZ value in the program

can be changed to 1.5, as shown in the input instruction (Section

5). Similarly, the TRACK value of a member is set to 0.0, which

means no allowable stresses of the member will be printed. If the

allowable stresses are to be printed, the TRACK value must be set

to 1.0.

Notes: The parameter names DMAX and DMIN are only used for

member selection. Once a parameter is specified, its value stays at



Table 16.1- American (API) Steel Design Parameters

Parameter

Name

Default

Value

Description



LY Member Length

Length in local Y-axis to calculate slenderness ratio.

LZ Member Length

Length in local Z-axis to calculate slenderness ratio.

FYLD 36 KSI Yield strength of steel.


UNL Member Length

Unsupported length for calculating allowable bending stress

UNF 1.0 Same as above provided as a fraction of actual member length

CB 1.0 Cb value as used in Section 1.5 of AISC 0.0 = Cb value to be calculated Any other value will mean the value to be used in design

MAIN 0.0 1.0 = Main member

2.0 = Secondary member

SSY 0.0 0.0 = Sidesway in local y-axis


Section 16

16-6

Table 16.1- American (API) Steel Design Parameters

Parameter

Name

Default

Value

Description

1.0 = No sidesway

SSZ 0.0 Same as above except in local z-axis

CMY

CMZ

0.85 for sidesway*

and calculated for no sidesway


TRACK 0.0 1.0 = Print all critical member stresses

100.0 = Suppress all checks except punching shear

DMAX 0.0 Maximum allowable depth

DMIN 0.0 Minimum allowable depth

RATIO Permissible ratio of the actual to allowable stresses

WELD 1 for closed sections

2 for open sections

Weld type, as explained in section 3.1.1.

1 = Welding is one side only except for wide flange or tee sections, where the web is always assumed to be welded on both sides.

2 = Welding is both sides. For closed sections like pipe or tube, the welding will be only on one side.

BEAM 1.0 0.0 = design only for end moments or those at locations specified by the SECTION command.

= calculate moments at twelfth points along the beam, and use the maximum Mz location for design.

WMIN 1.16 in. Minimum thickness

WSTR 0.4 X FLYD Allowable welding stress

LEG 1.0

2.0

To write out external parameters file.

To read in the external parameters file.

Section 16

16-7

16.7 Code Checking


section properties of the members are adequate as per API. Code

checking is done using the forces and moments at specific sections

of the members. If no sections are specified, the program uses the

start and end forces for code checking.


whether the members have passed or failed the checks, the critical

condition of API code (like any of the API specifications for

compression, tension, shear, etc.), the value of the ratio of the

critical condition (overstressed for value more than 1.0 or an y

other specified RATIO value), the governing load case, and the

location (distance from the start of the number of forces in the

member) where the critical condition occurs.


Section 2.2, American Steel Design, of the Technical Reference

manual.

16.8 Member Selection



select the most economical section, i.e. the lightest section which




also be constrained by the parameters DMAX and DMIN which


Member selection can be performed with all types of hollow steel

sections.


Section 16

16-8

Selection of members whose properties are originally input from a

user created table will be limited to sections in the user table.

Member selection cannot be performed on members whose section

properties are input as prismatic.

16.9 Truss Members

As mentioned earlier, a truss member is capable of carrying only

axial force. So in design, no time is wasted calcula ting the

allowable bending or shear stresses, thus reducing design time

considerably. Therefore, if there is any truss member in an

analysis (like bracing or strut, etc.), it is wise to declare it as a

truss member rather than as a regular frame member wi th both

ends pinned.

16.10 Punching Shear

For tubular members, punching shear may be checked in

accordance with the American Petroleum Institute (API) RP 2A –

20th Edition Section 4. The parameter PUNCH is used to identify

joint types for each end of the member where the punching shear

check is required. The PUNCH parameter is only read in from the

external geometry file. The external geometry file is described in

section 12.13. The PUNCH parameter is not specified within the

STAAD input file (the file with the .std extension).

Type of Joint and Geometry Req. Value of Parameter

PUNCH

K (overlap) 1.0

K (gap) 2.0

T & Y 3.0

CROSS 4.0

CROSS (with/diaphragms) 5.0

Section 16

16-9

Note: A value representing joint type and geometry must be

provided for parameter PUNCH, in the external file. On the first

run where no external table is present, LEG must equal 1.0.

16.11 Generation of the Geometry File

Automatic selection of the chord and brace members is performed

with the parameter LEG 1.0.

Two tubular members are used by the program to identify the

chord member. The chord members must be collinear (5 degree

tolerance).

The chord member must have a greater diameter and thickness

than the brace member being considered.

The punching shear check is performed on the joint treating it as a

T/Y joint. The yield stress of the brace is used. In the 50%

strength check the brace and chord yield are assumed to be the

same.

The major moment axis Mz is taken as In Plane Bending (IPB).

To change this, the parameter SWAP 1 should be used in the

external geometry file.

Note: The in-plane/out-of-plane correspondence can be set by

using the BETA angle.

If the punching shear cannot be performed at the joint for the

member being considered, a message is written to the output file

<filename>.ANL.

If a punching shear check is performed with the parameter LEG

1.0 used, then the geometry data used to perform the check is

written to the default external output file APIPUN.

The default external output/input file name can be changed by

using the command line:-


Section 16

16-10

CODE API <filename>.

This external output data file can be edited and used as an external

input file to re-perform the check using the parameter PUNCH 1.0

to 5.0.

This external input file allows can/stub geometry data to be

specified and chords to be assigned geometry where they could not

be identified in the Automatic selection.

The parameter LEG 2.0 must be used to read an external input file

where the default name is APIPUN.

The yield strength of the brace is used in the punching shear

check. This can be changed in the external geometry file. The

user should ensure that the correct cord member has been selected

for the check.

16.12 Chord Selection and Qf Parameter

Qf is a factor to account for the presence of nominal longitudinal

stress in the chord. When calculating Q f for the joints, the

moments used in the chord stress calculation will be from the

computer node results and not the representative moments

underneath the brace. If the moment varies significantly a long the

chord, it is more accurate to use the actual chord moment in the

middle of the brace foot print. The tests reported in Reference I1

were performed with a constant moment along the chord. Thus for

a local joint check, the local chord moment (under the brace)

should be used.

STAAD calculates Qf based on the moment at the chord member.

The chord member can be selected automatically by initial

screening by the program (based on geometry and independent of

loading) or specified by the user in the External file.

1 Ref I: Boone, TJ, Yura, JA and Hoadley, PW, Ultimate Strength if Tubular Joints – Chord

Stress Effects, OTC 4828, 1984

Section 16

16-11

In the automatic selection of the chord two collinear members (5

degree tolerance) are used to identify the chord. The chord is then

selected from one of the two members based on the larger diameter

then thickness or then by the minimum framing angle; for T joints

the first member modeled will be selected as the chord.

The user should confirm that the chord either be assigned by the

program or the user is representative of the local chord moment for

the brace in question.

16.13 External Geometry File

An example of the external geometry file is shown below:

BRACE CHORD PUNCH D T d T GAP FYLD THETAT TW SWAP

209 211 3 17.992 0.984 12.752 0.787 0.000 50.00 0.00 0.000 0

209 210 3 17.992 0.984 12.752 0.787 0.000 50.00 0.00 0.000 0

212 202 3 17.992 0.787 12.752 0.787 0.000 50.00 0.00 0.000 0

The parameters used in the external file are defined as follows:

Table 16.2 – External File

Parameter Description

PUNCH Parameter for punching shear (See Section 12.10)

BRACE Member number of brace CHORD Member number of chord D Chord Diameter in inches T Chord Thickness in inches d Brace Diameter in inches T Brace Thickness in inches GAP Gap in inches (must be negative for overlap

K-joint) FYLD Local yield strength used for joint in KIPS THETAT Angle of through brace in overlap K-joint in


Section 16

16-12

Table 16.2 – External File

Parameter Description

Degrees TW Used in overlap K-joint, taken as the lesser of

the weld throat thickness or thickness t of the thinner brace in inches

SWAP If parameter SWAP 0 is used then major moment Mz is taken for In Plane Bending (IPB). SWAP 1 uses the minor moment My as the IPB.

Notes:

For overlap K-joints, the through brace is assumed to be the

same diameter as the brace being checked.

If any of the parameters for diameter and thickness specified

in the external file are less than that for members being

checked, then the member properties specified in the STAAD

file shall be used.

The member diameter and thickness should be used in API

equation (4.1-1); in this check it has been assumed that the

yield strength of the chord and brace members are the same. The geometry file name is currently limited to eight characters

(4 if an extension as .txt is used).

The overall process of performing punching shear checks consists

of two steps. These steps are explained in section 12.16.

16.14 Limitations

The parameter SELECT 1.0 should not be used while carrying out

punching shear checks. It can be used in initial runs for member

selection.

No classification of the joint is performed using the loading.

No hydrostatic checks are performed.

Section 16

16-13

16.15 Tabulated Results of Steel Design




a) Member refers to the member number for which the


b) TABLE refers to AISC steel section name which has been

checked against the steel code or has been selected.

c) RESULTS prints whether the member has PASSed or

FAILed. If the RESULT is FAIL, there will be an asterisk

(*) mark on front of the member.

d) CRITICAL COND refers to the section of the AISC code


e) RATIO prints the ratio of the actual stresses to allowable

stresses for the critical condition. Normally a value of 1.0

or less will mean the member has passed.

f) LOADING provides the load case number which governed

the design.

g) FX, MY, and MZ provide the axial force, moment in local

Y-axis, and the moment in local Z-axis respectively.

Although STAAD does consider all the member forces

and moments (except torsion) to perform design, only FX,

MY and MZ are printed since they are the ones which are

of interest, in most cases.

h) LOCATION specifies the actual distance from the start of

the member to the section where design forces govern.

i) If the parameter TRACK is set to 1.0, the program will

block out part of the table and will print the allowable

bending stressed in compression (FCY & FCZ) and

tension (FTY & FTZ), allowable axial stress in

compression (FA), and allowable shear stress (FV).


Section 16

16-14

16.16 The Two-Step Process

The overall procedure for performing the code check per the API

code is as follows:

Step 1 – Creating the geometry data file. This is done by

specifying the name of the geometry data file alongside the

command line CODE API. If a file name is not specified, STAAD

automatically assigns the file name APIPUN to the geometry data

file. The parameter instructions in the .std file should contain the

LEG parameter and it should be assigned the value 1.0.

Example Reading External Geometry File

UNIT INCHES KIPS

PARAMETERS

* All joint data will be written to external file GEOM1 for

punching shear.

CODE API GEOM1

LEG 1.0

* Joints to be considered as T and Y, i.e. PUNCH is set to 3.0.

FYLD 50.0 ALL

TRACK 1.0 ALL

RATIO 1.0 ALL

BEAM 1.0 ALL

CHECK CODE ALL

After ensuring that your STAAD input file contains the above

data, run the analysis. Once the analysis is completed, you will

find that a file by the name GEOM1 has been created and is

located in the same folder as the one where your .std file is

located. (In case you did not specify a file name - GEOM1 shown

in the earlier example - STAAD will create the file named

APIPUN.

Section 16

16-15

Step 2 – The geometry data file (GEOM 1 or otherwise) should be

inspected and modified as required such as changing the PUNCH

values and local section properties for the punching shear checks.

Modify the .std file so it reruns the code check process by reading

the instructions of the GEOM file. This message is conveyed by

changing the value of the LEG parameter to 2.0. After making this

change, a re-analysis will result in the program using the

information in the geometry data file (GEOM1, APIPUN, or

otherwise) for performing the code check.

Example Reading an existing Joint Geometry Data File,

GEOM1

UNIT INCHES KIPS

PARAMETERS

* All joint data will be read from the external file GEOM1 for

punching shear.

CODE API GEOM1

LEG 2.0

FYLD 50.0 ALL

TRACK 1.0 ALL

RATIO 1.0 ALL

BEAM 1.0 ALL

CHECK CODE ALL


Section 16

16-16

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