Seismic And Vehicle-bridge Coupling Vibration Analysis Of Large-span Light-rail Bridges

As an important part of the urban lifeline engineering system,large-span light rail bridge is of great significance to study the dynamic performance of this kind of structure under earthquake and train load.This paper took a large span light rail continuous girder bridge in Tianjin Binhai Z2 line as engineering background,analyzed the bridge seismic isolation and vehicle-bridge coupling vibration.The main contents are as follows:(1)The existing friction pendulum bearing(FPB)model in the seismic analysis of the beam is improved to take into account the vertical dynamic reaction of the bearing and the validity of the method is verified by simulating the existing test results.The ANSYS software was used to establish the ordinary steel bearing,the bridge model considering and not considering the influence of the dynamic reaction force of the FPB were established.The displacement and the shear force of the pier were taken as the main control target.Basing on the different hysteresis curves of FPB while considering the influence of the vertical dynamic reaction,the vibration absorption of FPB in horizontal direction was mainly been analyzed under different ground motion,different bearing parameters and train load.(2)Considering the initial excitation such as track irregularity and wheel meandering motion,a suitable vehicle model is selected to realize vehicle-bridge coupled analysis in ANSYS.The influence of the speed variation on the displacement and acceleration response of the key nodes of the bridge has also been analyzed.(3)It was found that there is a certain degree of coupling between earthquake and train load in the vertical and transverse directions.The peak dynamic response of the bridge joint is greater than each one but under the summation of the twice.