2015 CSCE Annual Conference Regina - Building on our Growth Opportunities

2015 CSCE Annual Conference Regina - Building on our Growth Opportunities Conference

Numerical modeling of the stress ribbon Terwillegar Park Footbridge

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Mr. Nolan Rettie, Stantec Consulting (Presenter)
Mr. Shahab Ahmed, Stantec Consulting Ltd.
Dr. Manoj Medhekar, Stantec Consulting

The Terwillegar Park stress ribbon footbridge in Edmonton, Alberta began construction in 2014. The cable supported structures transfer large horizontal tension forces to the abutments, which are typically resisted by ground anchors. The vertical sag at midspan varies due to changes in temperature. Therefore, these structures do not require expansion joints, but geometry control during construction is critical. The superstructure analysis consisted of numerical modeling and analytical calculations. Results from both methods were compared to provide validation of the design. The numerical modeling methods are described. CSiBridge finite element software was used to create a staged construction analysis model. The construction model considered the various stages of construction including ground anchor stressing, tensioning the bearing cables, precast panel placement, cast?in?place concrete placement, post?tensioning the stressing cables, wearing surface and handrail installation. The model used constraints, as well as rigid and flexible links between nodes to accurately represent the appropriate construction stage. Construction and in?service temperature effects were included. Cable, truss, frame and shell elements were used for various bridge components. The numerical construction model compared well with the analytical results and will provide the designer with the ability to verify bridge geometry throughout all construction stages.