tiedarch_indepthdiscussion.pdf

MIDAS e-Learning Courses

Sharing Knowledge, Gaining Experience, Making Difference

Organized By MIDASoft, Inc.

MIDAS e-Learning Courses

What are “MIDAS e-Learning Courses”?

• Online technical service provided by MIDASoft

• Three technical courses (as a series):

1. Technical Seminar

2. In-depth Case Study and Discussion

3. Numerical Modeling and Analysis Training

Technical

Seminar

Case Study & Discussion

Numerical Modeling & Analysis

Training Purpose of e-Learning Courses?

• Contribute to our clients as a part of technical services

• Spread technology through sharing

• Bring happiness to engineers: lead to breakthroughs

Technical Seminar

Benefits

• Knowledge Sharing:

• Firsthand Information about design process

• Technical Overview of design consideration

• Learn about significant projects in North America by leading bridge

design companies

• Networking:

• Nationwide communication

Contents

• A professional engineer (Design firm, DOT’s, University)

• A specific bridge project and the considerations

• Challenges faced and how they were overcome

Technical Seminar

Yi-Lung Mo,

Ph.D.

Professor

University

of Houston

Hilliard C. Bond

P.E.

Principal

Construction

Engineer / Specialist

Parsons

Sezer Atamturktar,

Ph.D.

Assistant Professor

Clemenson

University

Amir Fam,

Ph.D., P.Eng.

Canada Research Chair in

Innovative and Retrofitted

Structures

Queens University

Gregor Wollmann,

PhD, PE

Sr. Structural Engineer

HNTB

Antonio Ledesma,

P.E.

Lead Structural Engineer

Parsons

Brinckerhoff

Upul Attanayake,

Ph.D., P.E.

Assistant Professor

Western Michigan

University

Neon Koon,

M.Eng, PE

Project Engineer

MMM Group

Travis Butz,

P.E.

Sr. Structural Engineer

Burgess & Niple

Craig Schaper,

P.E., P.Eng., C.Eng.,

MIStructE

Sr. Bridge Engineer

Associated

Engineering Ltd.

Anoosh Shamsabadi,

PhD, PE

Sr. Bridge Engineer

Caltrans

Daniel Baxter,

P.E., S.E.

Bridge Engineer

Michael Baker Jr,

Inc.

In-depth Case Study & Discussion

Contents:

• Covering Technical Seminar topic

• Detailed discussions on:

• Related case studies in US & Canada

• Latest technologies for numerical modeling in bridge engineering

Benefits

• Advantages of finite element analysis in bridge

engineering

• Explore efficient approaches for modeling, analysis &

design of bridges

• Use the latest technology in your everyday design work

In-depth Case Study & Discussion

Numerical Modeling and Analysis Training

Benefits:

• Learn correct numerical modeling

• Become a master of modeling different types of bridges

• Explore concepts of different analysis

• Get latest updates of North America design codes

Contents:

• Step by step modeling of bridge projects

• Modeling techniques

• Output extraction and interpretation

• Design check for code satisfaction

Numerical Modeling and Analysis Training

Upcoming Events

Feb. Series DATE COURSE CONTENTS

2/07 Technical Seminar

(Dr. Gregor Wollmann) Network Tied Arches

2/14 In-Depth Case Study & Discussion CAE Solutions for Network Ties Arch Bridges

2/21 Numerical Modeling & Analysis Training How To Utilize midas Civil for Network Tied Arch

Bridge Design

In-Depth Case Study & Discussion of

Network Tied Arch Bridges

midas Civil

Bridging Your Innovations to Realities

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Outlines

1 • Case Study of Happy

Hollow Park Network Tied Arch

• General information, Geometry, Dimensions

2 • Advantages of

Network Tied Arches

• Comparison with conventional Tied Arches

3 • Design of Network tied

Arches

• Erection (construction) methods

• Design and Erection Considerations

• Finite Element solutions for design and construction of Network Tied Arches

Overview

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Case Study

Part 1

Case Study

General information, geometry, dimensions

Part 1

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• Project Name: Happy Hollow Park and Zoo Network Tied Arch Pedestrian Bridge

• Location: San Jose, CA

• Owner: City of San Jose, CA

• Principal Contractor: Anderson Pacific, Santa Clara, CA

• Structural Engineer: HNTB Corporation, New York, and San Jose

• Bridge Length: 540 ft (two spans of 270 ft)

Part 1 Case Study

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Case Study Part 1

Geometry

• Arch radius: 225 ft

• A basket handle configuration arrangement, transverse distance of the spring line: 13 ft

• Hangers are galvanized ¾-in. diameter bridge strand with simple, swaged pin connections

at both ends

• Totally 88 inclined hangers, cable inclination angle from 57 to 71 degree

• The hanger spacing is constant along the arch rib at approximately 6.5 ft

• Design Load: Pedestrian traffic and a 5-ton maintenance vehicle

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Case Study Part 1

.

Cable Stayed Falsework with installed Hangers

Pretensioned

Cable Stayed Falsework with all Hangers

installed and Pretensioned

Cable Stayed Formwork removed

East Arch Erection

• cable stayed falsework system

• The arch was much stiffer than the cable supported falsework and therefore picked up the

majority of the superimposed load.

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Case Study Part 1

Geometric Non Linear Construction stage analysis was performed to obtain the geometric

non linear effects.

Construction Stage Results

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Case Study Part 1

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Advantages of Network Tied Arches

Part 2


- Tied Arch vs Network Tied Arches

- Advantages

Part 2

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Advantages of Network Tied Arch Part 2

Tied Arch with vertical hangers

Network Tied Arch

www.network-arch.com

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Network Tied Arch Bridges:

Definition

Network arches are bowstring arch bridges with inclined hangers which have multiple

intersections."


• Inclined hangers causes better moment/shear distribution

• Stiffer structure due to more redundancy

• Feature slender arch cross sections and a slim tie

• Can save up to 45% of the total costs compared to conventional tied arches

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Advantages of Network Tied Arch

Maximum deflection under Moving Load

Part 2

Network Tied Arch vs Conventional Tied Arch

• Stiffer structure compared to tied arches

• Critical Live Load: partially loaded

• Lesser displacement

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• Smooth moment distribution on Arch & Tied Girder

• Tie and hangers give the arch good support and high buckling

strength in the plane of the arch

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• Network arches are not sensitive to uneven settlements in the

foundations.

• High strength and low weight give the network arch good

resistance to earthquakes.

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Design and Construction Considerations

Part 3


a) Design of Network Tied Arches

b) Erection (construction) methods

c) Design and erection considerations

d) FE solution for design & construction

Part 3

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Design and Construction Considerations Part 3

Design of Network Tied Arch

1. Construction Stage:

• Stability of structure in intermediate stages

• Nonlinear behavior of cables

• Wind effect during construction

• Temporary supports situation

2. Final Stage:

• After arch are placed calculate cable forces (Cable Tuning)

• Correct geometry

• Consider linear behavior of elements (concrete slab, cables)

• Critical live load (partially loaded)

• Extraordinary Loads (accidental hanger loss)

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Different methods of Network Tied Arch erection

• Fabricate onshore, then place at the right location

• Erect arch ribs and tie girders, then install cables

o Using false work

o Using cable stay

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An advanced method of erection

suggested for the Bechyne Bridge

Part 3

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Happy Hollow Park Network Tied Arch Pedestrian Bridge

Part 3

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1. Design for Construction Stage:

- Stability, slender elements

- Need to provide requires stress in cables during arches and tie erection

- Nonlinear geometry

- Lack-of-Fit force

- Wind combination in intermediate stages

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Initial Tangent Displacement

- To keep track of deflected shape across construction stages.

- Camber diagram

Lack-of-Fit Force

- For restraint forces during arch closure

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- Cables are not straight,

- Need to use nonlinear element

Elements:

- Cable Elements work will with non-linear analysis (geometry nonlinearity)

- Reported results include sag, chord force, true end forces, end rotations and analysis

reflects reduced stiffness due to sag effects

- Truss & beam elements

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- Time dependent analysis

- Creep & Shrinkage

- Compressive strength of concrete

Composite Section Properties

- shift of neutral axis due to deck activation is properly accounted for in a construction

staging analysis. This is important for composite elements subject to axial force in

addition to bending moment

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2. Design for Final Stage :

• Linear behavior of cables

• Hanger force adjustment:

• a optimization problem with high number of parameters

• In case of Happy Hollow Park Network Tied Arch: 88 hangers

• Hand calculation (spreadsheet): very big matrix

• Using the software

• Moving load analysis:

• Critical loads

• Static analysis

• Extraordinary load:

• Accidental hanger loss

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Hanger Force Adjustment:

- Optimization problem

- Useful to create influence matrix needed for hanger tuning

- Generate the influence matrix which can then be written directly to Excel

Function 1:

Unknown Load Factor

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v


Function 2:

Cable Tuning

Steps:

1. Adjust the cable pretension (or load

factor)

2. Select the result item

3. Produce the results graph for the result

item selected from step 2

4. Save the adjusted pretension forces in a

load combination or apply the new

pretension forces to the cables directly

using the pre-programmed buttons

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Moving Load Tracer:

- Influence line

- Moving Load Tracer (Critical moving)

- Equivalent static load (critical live loads)

- Save time of rerunning after design changes

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Pdyn = - AF ·Pstat

Equivalent static analysis: • PTI Recommendations: AF = 2.0 • Dynamic analysis: AF = 1.58 ~ 1.81

Extraordinary Loads:

Hanger Loss:

- When one hanger is missing, load will be distributed to other elements

- Dynamic effect

- Time History analysis

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Time History Analysis:

- Useful to investigate sudden loss of one or several hangers, or tie girder elements

- Can quickly modify fracture sequence, arrival time, ramp time.

Upcoming Events

UPCOMING TECHNICAL SEMINARS

DATE SPEAKER COMPANY TOPIC

3/07 Benjamin Szymanski

Parsons Brinckerhoff

Displacement Time History Analysis of a Long Span Bridge

3/14 Ling Zhao Michael baker RS Analysis and Seismic Design of Conventional Bridges

3/28 Deanna Nevling Michael baker

Analysis of Parameters Influencing Curved Steel I-Girder Bridges During Construction

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Sharing Knowledge, Gaining Experience, Making Difference

Organized By MIDASoft, Inc.

Thank You

[email protected]

646-852-9289

Date post:	23-Dec-2015
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tiedarch_indepthdiscussion.pdf

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