Seismic Response of Girder Bridges in Liquefiable River Valleys with Different Structural Configurations

Abstract:

Seismic responses of girder bridges may vary due to different structural systems and foundation types. In this regard, based on typical threespan girder bridges in liquefiable river valleys, three 2dimensional finite element models considering soilstructure interaction were built, including simply supported girder bridge with pile group foundations, continuous girder bridge with pile group foundations, and simply supported girder bridge with pileshaft foundations. Nonlinear time history analyses were performed to investigate the seismic response properties of these bridges. Postearthquake deformations of the soil and bridge, pile deformations, column drift ratios, bearing displacements, and expansion joint deformations were investigated to reveal the impact of soil liquefaction on seismic responses of these three types of bridges. The numerical results show that soil liquefaction significantly increases the unseating potential of the simply supported girder bridge with pile group foundations. For abutments of continuous girder bridge, unseating or abutmentdeck collision potentials are generally increased. In contrast, seismic responses of the simply supported girder bridge with pileshaft foundations are rarely influenced by soil liquefaction.