DYNAMIC RESPONSE OF LONG CONTINUOUS RIGID-FRAMED BRIDGE SUBJUCTED TO TRAIN AND SEISMIC MULTI-SUPPORTS EXCITATIONS

摘要

This study is intended to investigate the dynamic response of long continuous rigid-framed bridges subjected to train and seismic loads. When the train runs through the bridges, the bridges may be subjected to earthquake, which will cause extra dynamic response. In order to study this problem, the bridges are modeled as 3-D beam elements and the wheel loads of train are simplified as the force on the beam elements. Seismic responses of the bridges are calculated by means of dynamic time-history method. The seismic record is selected according to the design principle, which means that the earthquake will occur very possibly and the bridge severs under such an earthquake. Wave passage effect, incoherence effect and local effect are considered in the numerical simulation. A case study is implemented on the Baima River bridge on the Wenzhou-Fuzhou Highspeed Railway in China, dynamic response of this vehicle/bridge system under earthquake load is analyzed with a train running through the bridge, which is a passenger train at 200km/h velocity. The dynamic performances of this bridge alternative under earthquake and moving train effects is evaluated. The long-span bridge response under multiple excitations may be more intensive than those under uniform excitations when train is running through.