Experimental and numerical studies of the seismic behavior of a steel-concrete composite rigid-frame bridge subjected to the surface rupture at a thrust fault

Bridges crossing fault are vulnerable to surface fault ruptures. Previous studies on this topic are limited especially for thrust faults. It is necessary to examine the performances of fault-crossing bridges subjected to earthquake-induced surface fault rupture. This study investigates the seismic behavior of a recently proposed steel-concrete composite rigid-frame bridge (SCCRFB) with concrete-filled double skin steel tube (CFDST) piers subjected to the earthquake-induced surface rupture at a thrust fault. Shake table tests on a 1:10 scaled three-span SCCRFB subjected to across-fault ground motions were performed first. Detailed 3D finite element (FE) model of the bridge is then developed by using LS-DYNA and validated by the experimental results. The effects of the key parameters that influence the bridge responses to surface ruptures including the location of the fault, fault-crossing angle and fling-step are systematically investigated. Experimental and numerical results reveal that this novel bridge type has a very good seismic resistance capability.