UCLA

Recently developed guidelines for analyzing deep foundations in liquefiable soils are compared with the performance of a highway bridge and adjacent railroad bridge that suffered damage during the 2010 Mw 7.2 El Mayor-Cucapah earthquake in Baja California, Mexico. A span of the pile-supported railroad bridge collapsed due to movement of a pier from lateral spreading. The highway bridge, supported on drilled shafts, suffered moderate structural damage but did not collapse. An overview of the site, structural details of the bridges, and results from recent geotechnical explorations characterize the structural properties and soil conditions. Beam on nonlinear Winkler foundation simulations performed using the finite element program OpenSees accurately predict moderate damage to the highway bridge and collapse of the railroadbridge. The case studies provide valuable insight for validating recently published equivalent static analysis procedures for lateral spreading.