Prepared by:Ayman Naalweh

Mustafa MayyalehNidal Turkoman

An-Najah National University

Faculty of Engineering

Civil Engineering Department

Graduation Project:

3D Dynamic Soil Structure Interaction Design For Al-Manar Building

Supervised By

Dr: Imad AL-Qasem

3D’s For Al-Manar Building

GRADUATION PROJECT

December 2010

SUBJECTS TO BE COVERED

Abstract Chapter One : Introduction Chapter Two : Slab Chapter Three : Beams Chapter Four : Columns Chapter Five : Footing Chapter Six : Checks Chapter Seven : Dynamic Analysis Chapter Eight : Soil Structure Interaction

Abstract

AL-Manar building composed of seven stories office building. Each floor is composed of equal surface area of 1925 m2 with 3.5 meter height and long spans.

The building analyzed under static loads using SAP 2000v12.

After that the building was analyzed dynamically. Finally it was designed based on Soil Structure

Interaction (SSI).

INTRODUCTION

About the project: (AL-Manar) building in Ramallah, is an office building

consists of seven floors having the same area and height, the first floor will be used as a garage.

Philosophy of analysis & design:

SAP2000 V12 is used for analysis and ultimate design method is used for design of slab, the slab are carried over drop beams.

INTRODUCTION

Materials of construction: Reinforced concrete:

(ρ) = 2.4 ton/m3 ,

The required compressive strength after 28 days is

fc = 250 kg/cm2,

For footings fc =280 kg/cm2

For columns fc = 500 kg/cm2

Fy =4200 kg/cm2

Soil capacity = 3.5 kg/cm²

INTRODUCTION

loads:

Live load: LL=0.4 ton/m2

Dead load: DL=(Calculated By SAP) , SID= 0.3 ton/m2

Earthquake load: its represents the lateral load that comes from an earthquake.

INTRODUCTION

Combinations:

Ultimate load= 1.2D+1.6L

Codes Used: American Concrete Institute Code (ACI 318-05) Uniform Building Code 1997 (UBC97)

SLAB

One way solid slab is used : Thickness of slab: t = Ln/24 =12.9 cm use 15 cm ,d=12 cm Slab consists of two strips (strip 1 & 2)

SLAB

ANALYSIS AND DESIGN FOR SLAB : STRIP 1 :

SLAB

M+ve. = 1.28 ton.m

 

ρ= 0.0024

As bottom = ρ* b* d = 2.8 cm2

Ast = ρ shrinkage * b*h = 0.0018*100*15= 2.7 cm2

Use 1 ф 12 mm /30 cm

SLAB

M –ve= 1.75 ton.m

ρ= 0.0028

Ast top = 3.66 cm2

Use 1 ф 12 mm/ 25cm

Shrinkage steel = 1 ф 12 mm / 30 cm

Check shear :

Vu= 2.95 ton at distance d from face of column.

Ф Vc = ф (.53) (10) (b) (d) =0.75*0.53**10*1.0*0.12

= 7.54 ton > 2.95 ton. Ok

BEAMS

BEAMS SYSTEM:

Beams will be designed using reaction method(Loads from slab reactions) in this project, all the beams are dropped, multi spans and large space beams.

Beam 1(0.8*0.3)

Beam 2(0.8*0.4)

Girder 1(0.9*0.3)

Girder 2(0.9*0.6)

Ast TOP 15.01 cm2 43.7 cm2 39.7 cm2 97.68 cm2

# of bars 4 ф 22 mm 12 ф 22 mm 9ф 25 mm 20 ф 25 mm

Ast BOTTOM 14.40 cm2 41.32 cm2 32.6 cm2 78.5 cm2

# of bars 4 ф 22 mm 11 ф 22 mm 9 ф 22 mm 21 ф 22mm

BEAMS

DESIGN OF BEAM 1:

BEAMS

DESIGN OF BEAM 1:

BEAMS

DESIGN OF BEAM 1: Positive moment on beam 1: M+ve = 38.44 ton.m =0. 00624

As bottom = ρ* b*d = 14.4 cm2

 

As min = 0.0033*b*d=0.0033.*30*76=7.54 cm2 < 14.4 cm2

Use 4 ф 22 mm

BEAMS

DESIGN OF BEAM 1:Negative moment on beam 1:

M -ve= 40.34 ton.m

ρ = 0.0066

As top = 15.01 cm2

Use 4 ф 22 mm

Min. beam width = ndb +(n-1)S+2ds+2* cover

b min = 4(2.2)+ 3(2.5)+2(2.5) +2(1)

=23.3 cm < 30 cm ok

COLUMNS

Columns System : Columns are used primarily to support axial compressive

loads, that coming from beams that stand over them. 24 columns in this project are classified into 2 groups

depending on the ultimate axial load and the shape. The ultimate axial load on each column is calculated from

3D SAP, and the reaction of beams as shown in next table :

3D (SAP)(ton)

Hand calculation

(ton)

3D (SAP)(ton)

Hand calculation

(ton)

C1 451.1 284.1 C13 858.3 759.8C2 901.8 711.4 C14 1425.5 1859.3C3 852 711.4 C15 1425.7 1859.3C4 462.6 284.1 C16 857 759.8C5 852.4 869.1 C17 852.6 869.1C6 1796 2126.2 C18 1786.9 2126.2C7 1723.4 2126.2 C19 1786.5 2126.2C8 863.1 869.1 C20 851.9 869.1C9 858.6 759.8 C21 453.1 284.1

C10 1425.4 1859.3 C22 895.9 711.4C11 1425.7 1859.3 C23 895.1 711.4C12 856.2 759.8 C24 451.8 284.1

COLUMNS

Design of columns: the capacity of column:

ФPn max = ф λ {0.85 'c (Ag - Ast) + y Ast} 𝒇 ℱ Ast = 0.01 Ag (Assumed)

All columns are considered as short columns .

Column type Tied column Spiral column

Ф 0.65 0.7λ 0.8 0.85

COLUMNS

Group (1) Group (2)C1 C13 C6C2 C16 C7C3 C17 C10C4 C20 C11C5 C21 C14C8 C22 C15C9 C23 C18C12 C24 C19

Columns Groups :

COLUMNS

Design columns in group (1): Pu = 980 ton

Check buckling:

The column is short

K: The effective length coefficient (=1 braced frame )

Lu: unbraced length of the column

r: radius of gyration of the column cross section

Let = 1 , = 16.67 < 22 → ok short column.

ФPn max = ф λ {0.85 'c (Ag - Ast) + y Ast}𝒇 ℱ

Let

b

b

M

M

2

1

= 1

COLUMNS

Design columns in group (1):

→ Ag = 4073 cm2

Use 70*70 → Ag = 4900 cm2

→ Ast = 0.01× 4900 = 49 cm2 (use 20 Ф18)

Spacing between stirrups:Spacing between stirrups shall not exceed the least of the following:

1) At least dimension of the column = 70cm 

2 )16db = 16*1.8 = 28.8 cm   3) 48ds = 48*1.0 = 48 cm

use Ties (1 ф 10 mm/25 cm c/c)

Let

= 1

COLUMNS :

Summary:

Group 1 Group 2

Ultimate load (ton)

980 1900

dimensions (cm) 70*70 Dia. = 95

Reinforcement 20 Ф18 28 Ф18

Stirrups / Spiral Ф10 mm Ф10 mm

Spacing (cm) 25 5

cover (cm) 2.5 cm 2.5 cm

FOOTING :

FOOTING SYSTEM: All footings were designed as isolated footings. The design depends on the total axial load carried by

each column. Groups of footings :

Groups Footing

Group 1 F1, F4,F21,F24

Group 2 F2, F3,F5,F8,F9,F12,F13,F16,F17,F20, F22, F23

Group 3 F6,F7,F10,F11,F14,F15,F18,F19

FOOTING :

Summary :

Group 1 Group 2 Group 3

Dimensions (m) 3.4*3.4 4.7*4.7 6.5*6.5

Thickness (cm) 70 110 130

Steel in x direction (cm2/m ) 17.62 23.12 37.6

Steel in y direction (cm2/m ) 17.62 23.12 37.6

Cover (cm) 5 5 5

FOOTING :

Group 2 using sap :

FOOTING :

Group 2 using sap :

Moment per meter in x& y =395.66/4.7= 84.18 ton.m/m Compare it with hand calculation Mu= 88.73 ton.m % of error = 88.73-84.18/84.14 = 5.4 %

FOOTING :

Tie Beam Design: Tie beams are beams used to connect between columns

necks, its work to provide resistance moments applied on the columns and to resist earthquakes load to provide limitation of footings movement.

Tie beam was designed based on minimum requirements with dimensions of 30 cm width and 50 cm depth.

Use minimum area of steel , with cover = 4 cm.

Ast Top bars Bottom bars stirrups

4.46cm2 4 Φ 12 mm 4 Φ 12 mm 1 Φ 10 / 20cm

CHECKS

Check Compatibility: This requires that the structure behave as one unit, so the

computerized model should achieve compatibility, to be more approach to reality.

CHECKS

Check of equilibrium: Dead load:

Columns :

Type of column

Number of columns

dimensions (m)Weigh per

unit volume

weight (ton)

Tied 112 3.5 0.7 0.7 2.4 3.5*0.7*0.7*2.4*112 = 460.99

Spiral 563.5 D= 0.95 2.4

(π/4 *0.952 )*3.5*2.4*56= 333.42

Total 794.41

CHECKS

Slab : Area of slab =1846.2m

Weight of slab = 1846.2*2.4*0.15*7 = 4652.42 ton

Beams : Type of beam

Number of beams

dimensions (m)

Total length

Weigh per unit volume

weight (ton)

Ground beams

1120.3 0.5 404.4 2.4 0.3*0.5*2.4*404.4 = 145.58

Beam 1 42 0.3 0.8 77 2.4 0.3*0.8*2.4*77*7 = 310.46Beam 2 98 0.4 0.8 516 2.4 0.4*0.8*2.4*516*7 = 2774.14Girder 1 112 0.3 0.9 102 2.4 0.3*0.9*2.4*102*7 = 462.71Girder 2 112 0.6 0.95 102 2.4 0.6*0.9*2.4*102*7 = 946.75

Total 4359.18

CHECKS

Super imposed dead load:Super imposed dead load = area of slab* Super imposed on slab

= 1846.2*0.3*7 = 3877.02 ton

Total dead load = columns +slabs +beams +super imposed

= 794.41+4652.42+3877.02+4359.18 =13683.03 ton

Results from SAP: Dead load = 13947.82 ton

Error in dead load: %of error = (13947.82 -13683.03)/ 13683.03 = 1.9% < 5% ok

CHECKS

Live load:Live load = area of slab* live load

= 1846.2*0.4*7 = 5169.36 ton

Results from SAP: Live load = 5169.36

Error in live load: %of error = (5169.36 - 5169.36 )/5169.36 = 0% < 5% ok

CHECKS

Check stress strain relationship:

Taking beam 1 as example:

Stress –Strain relationship is more difficult check compared with others, because of the large difference between values of 1D and 3D model, which usually appears during check .

Max M+ Ext. (Ton.m) Max M- Int. (Ton.m) 1D 3D %of error 1D 3D %of error

38.44 43.18 12.3 40.34 35.4 13.9

DYNAMIC ANALYSIS

Period of structure : Fundamental period of structure depends on the nature of

building, in terms of mass and stiffness distribution in the building .

(Define area mass for building)

DYNAMIC ANALYSIS

DYNAMIC ANALYSIS

Check the modal response period from Sap by Rayleigh method

Approximate method calculation:Rayleigh law: period = 2 , Where:M = mass of floor

= displacement in direction of force (m)

F: force on the slab (ton)

DYNAMIC ANALYSIS

Level mass force delta mass*delta2 force*delta period (sec)

7 196.6 1846.2 1.97 762.9849 3637.0146 196.6 1846.2 1.88 694.863 3470.8565 196.6 1846.2 1.74 595.2262 3212.3884 196.6 1846.2 1.54 466.2566 2843.1483 196.6 1846.2 1.27 317.0961 2344.6742 196.6 1846.2 0.94 173.7158 1735.4281 196.6 1846.2 0.52 53.16064 960.024

sum 3063.303 18203.53 2.58

Rayleiph method calculation for 7 stories in x- direction :

DYNAMIC ANALYSIS

Response spectrum :

Analysis input:IE: seismic factor (importance factor) = 1.0

R: response modification factor (Ordinary frame) = 3

PGA: peak ground acceleration = 0.2 g

According to seismic map for Palestine (Ramallah city)

Soil type: SB (Rock)

Ca: seismic coefficient for acceleration = 0.2

Cv: seismic coefficient for velocity = 0.2

Scale factor = = 3.27

DYNAMIC ANALYSIS

Definition of response spectrum function :

DYNAMIC ANALYSIS

Define of earthquake load case in x-direction :

DYNAMIC ANALYSIS

Base reaction for Response Spectrum :

DYNAMIC ANALYSIS

Summary:

Direction Modal period )sec (

Base Reaction of Qauke (ton)

Displacment )cm(

X-direction ( U1 ) 2.63 321.7 5.28

Y- direction ( U2 ) 2.15 393.3 4.64

SOIL STRUCTURE INTERACTION (SSI)

The process in which the response of the soil influences the motion of the structure and the motion of the structure influences the response of the soil is termed as soil-structure interaction (SSI).

Neglecting SSI is reasonable for light structures in relatively stiff soil such as low rise buildings, however, The effect of SSI becomes prominent for heavy structures resting on relatively soft soils .

SOIL STRUCTURE INTERACTION (SSI)

Soil structure model from SAP

SOIL STRUCTURE INTERACTION (SSI)

ANALYSIS AND DESIGN FOR BEAMS: Beam 1:

SOIL STRUCTURE INTERACTION (SSI)

M+ ext. = 32.73 ton.m

 

ρ= 0.0053 As bottom = ρ* bw* d = 12.0 cm2

SOIL STRUCTURE INTERACTION (SSI)

SUMMARY:Max M- Ext. Max M+ Ext. Max M- Int. Max M+ Int.

BEAM Normal1D

SSI3D

Normal1D

SSI3D

Normal1D

SSI3D

Normal1D

SSI3D

BEAM1 0 -58.21 38.44 32.73 -40.34 -35.86 0.32 17.37BEAM2 0 -109.32 96.69 57.93 -101.64 -40.35 2.06 18.02Girder1 0 -72.2 87.87 41.91 -103.58 -76.12 53.87 40.56Girder2 0 -155.28 220.14 100.7 -258.58 180.4 90.21 94.56

Ast cm2 Ast cm2 Ast cm2 Ast cm2

BEAM1 0 22.4 14.23 11.05 14.99 13.33 0.1 6.2BEAM2 0 48.3 41.32 23.08 43.9 15.64 0.8 6.7Girder1 0 25.86 31.1 14.4 39.68 27.7 17.93 13.38Girder2 0 52.01 78.49 32.68 93.9 62.8 28.84 31.12

SOIL STRUCTURE INTERACTION (SSI)

SUMMARY:Max S- Ext. Max S+ Ext. Max S- Int. Max S+ Int.

BEAM Normal1D

SSI3D

Normal1D

SSI3D

Normal1D

SSI3D

Normal1D

SSI3D

BEAM1 -13.85 -24.35 19.82 21.5 -14.34 -15.83 -13.85 14.34BEAM2 -36.8 -48.14 51.23 42.25 -37.07 -29.74 37.07 29.69Girder1 -26.95 -34.91 47.26 35.13 -39.16 -34.72 34.59 34.23Girder2 -66.83 -86.87 117.53 88.4 -98.42 -85.91 85.49 87.1

Spacing(Ф10)(cm)

Spacing(Ф10)(cm)

Spacing(Ф10)(cm)

Spacing(Ф10)(cm)

BEAM1 35 35 35 35 35 35 35 35BEAM2 25 13 13 13 25 25 25 25Girder1 20 20 20 20 20 20 20 20Girder2 15 15 15 15 15 15 15 15

SOIL STRUCTURE INTERACTION (SSI)

ANALYSIS AND DESIGN FOR SLAB: STRIP 2:

SOIL STRUCTURE INTERACTION (SSI)

M+ ve=1.18 ton.m

 

b=100 cm, d=12 cm ρ = 0.00221 As bottom = ρ* b* d = 2.6 cm2

As min. =2.7 cm2

Use 1 ф 12 mm /30 cm

SOIL STRUCTURE INTERACTION (SSI)

SUMMARY: