Seismic Response Analysis of Simply Supported Curved Girder Bridge with Friction Pendulum Bearing Under Rare Earthquakes

Isolated bridges may suffer serious damage under rare earthquakes, including excessive relative displacement and girder falling. To evaluate the seismic isolation performance of a simply supported curved girder bridge with a friction pendulum bearing (FPB) under rare earthquakes, the mechanical model for the collision function and the pile–soil interaction model are established based on the Kelvin collision model and the M-method, respectively. A nonlinear dynamic numerical simulation model of a seven-span simply supported bridge with FPB was established using SAP2000 v14. Parametric studies were then carried out to investigate the effects of curvature radius and pier height on the dynamic responses of the bridge system. The results indicate that the seismic capacity of a simply supported bridge with FPB will be seriously overestimated if only a unidirectional seismic wave is adopted, which leads to an insufficient seismic design safety margin for the bridge. The smaller curvature radius of the bridge has a more obvious effect on the dynamic response of the bridge, and the influence of curvature radius on the curved segment is significantly greater than that on the straight segment. The pier height has little effect on the dynamic response of the main beam due to the excellent isolation effect of FPB.