Seismic Study of An Isolated Cable-Stayed Bridge under Near-Fault Ground Motions

During strong earthquakes, pounding may occur on large-span bridges and their approach bridges. The effect and mitigation measures of such pounding have rarely been explored in previous studies. This paper primarily uses finite element models to investigate the pounding effects at the expansion joints between the main cable-stayed bridge and its approach bridge. Friction pendulum bearings (FPBs) and fluid viscous dampers (FVDs) are used to alleviate poundings. Furthermore, a detailed analysis is conducted on how the pounding effect of the isolated main bridge with FPBs and FVDs is affected by the wave passage effect, ground motion type, and soil type. This study reveals that FPBs and FVDs can effectively reduce pounding effects and the associated risks. Even with the installation of FPBs and FVDs, lower seismic wave velocities and near-fault seismic motions with pulse effects can significantly increase the pounding effects between the cable-stayed bridge and its approach bridge.