MIDAS Logo
MIDASoft Timer

GET IT NOW x

 

 

 

 




go back button
Aaron Colorito
By
November 12, 2018

Self-Anchored Suspension Bridge - Andy Warhol Bridge (PA)

 

 

 

 

 

Synopsis of the Presentation

Aaron B. Colorito, Bio

 

Project Information
- Located in Pittsburgh, PA over Allegheny River
- Second bridge at this site
- Replaced 1884 Gustav Lindenthal suspension bridge
- Mandated by 1889 River and Harbor Act
- First self-anchored suspension bridge in U.S.
- Constructed by American Bridge Co. and Foundation Co. of NY
- First of the “Three Sisters” constructed from 1924-1928

 

20180717_153752

 

Key Technical Issue 1: Self-Anchored Suspension Bridge (SASB) Mechanics
- Need for end anchorages eliminated
- Reduces right-of-way required
- Girder sized for compression & flexure
- Analysis by the elastic theory as an independent check
- Deflection theory of suspension bridges also applicable, may be reduced to elastic theory
- Special considerations for live load analysis

Overview of the Traditional vs. Self-Anchored Suspension Bridges

Traditional Suspension Bridge vs Self-Anchored Suspension Bridge

 

Key Technical Issue 2: Create Finite Element Model for SASB for various purposes
A series of models are created for different purposes:
- Geometry
- Initial Force System
- Loading & Boundary Conditions
- New Dead Loads
- Moving & Static Live Loads
- Construction Staging (Deck Removal & Pouring Sequences)
- Pedestrians-Only Load Case

Elevation view of the FEA model, cross section and ISO view


FEA Modeling Process
1. The initial model is created using the Suspension Bridge Wizard of midas Civil. However, the Suspension Bridge Wizard creates the normal (externally-anchored) suspension bridge model. Therefore, further modifications were made to convert the model to be self-anchored.

20180717_154023

 2. Manual modifications are made in order to reflect the self-anchorage system. The Post-Wizard Modifications are:
- Replace end boundary conditions
- Insert floor system (floorbeams and stringers)
- Insert rigid links at girder/chain ends
- Modify Suspension Bridge Analysis Control

 20180717_154103

3. Additional Studies and FEA modeling are done for the study of the following issues:
- Moving & Static Live Loads
- Construction Staging (Deck Removal & Pouring Sequences)
- Pedestrians-Only Load Case

20180717_155010

Key Technical Issue 3: Results & Verification (Expectations vs. Reality)

The expectations such as below:
- Elastic Theory will give larger dead load forces
- Stiffening girder end moments same sign
- Stiffening girder DL moments same order of magnitude

For the reality, the plan sheet forces, the elastic theory and MIDAS results are compared:

20180717_155106

20180717_155135

 

 

suspension_tutorial

Do you want to learn how to use? Click Here

 

 

 


 

 speaker-icon1

Speaker :  Aaron Colorito, PE, CBSI

Category : Bridge

Software : midas Civil

Date : 2016-08-03

 


 





Comments



Keep Updated With Technical Contents 

Keeping You Updated