Join us at Geo-Congress 2019

March 22, 2019

Ali Ghandeharioon, Ph.D., P.Eng., a Geotechnical Engineer at KCB will be presenting a poster at Geo-Congress 2019: 8th International Conference on Case Histories in Geotechnical Engineering, in Philadelphia, PA on March 24-27, 2019.

The poster is based on the paper titled “Seismic Retrofit Design of a 110-year Old Railway Bridge Founded on Liquefiable Soils Using Large Diameter Driven Piles” which he co-authored with KCB colleagues James Williams, M.Sc., P.Eng. and Bruce Hamersley, P.Eng., Manager, Bridge Engineering.

The poster will be presented on Monday, March 25th from 3:30 pm to 5:30 pm in Exhibit Hall E at Loews Philadelphia Hotel.

Presentation Summary

A seismic retrofit design was carried out for an existing 110-year old railway bridge crossing a wide river. The existing foundations that have performed acceptably under static conditions, are founded on potentially liquefiable soils. A retrofit strategy was developed using large diameter driven pipe piles to transfer the bridge loads to non-liquefiable glacial till in a seismic event. The retrofit design is required to withstand a 475-year return period earthquake. Nonlinear seismic deformation analyses were performed using the finite difference program FLAC and effective stress-based constitutive model UBCSAND to evaluate the dynamic response of foundation soils and retrofit piles by considering soil-pile interactions. The deformation analyses show that the overall riverbed flattens during the seismic event, and the retrofit pile heads undergo a horizontal displacement of up to 0.5 m. The existing bridge bearings will be replaced with new sliding-plate bearings designed to accommodate the upper-bound pile head displacements predicted by the FLAC analyses.

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