Pounding Effect For Simply Supported Beam Bridges Of High Speed Railway Under Strong Earthquakes

Damages caused by pounding between adjacent bridge girders were found during all previous strong earthquakes. Most existing research on pounding effect was carried out for highway or urban bridges, but rarely for high speed railway bridges. In this paper, the influences of pounding effect on seismic response of high speed railway bridges are investigated, and the main research contents are as follows:(1) A three-span simply supported bridge’s finite element model is created with the ANSYS software, and the Kelvin model is selected to simulate the pounding process. A new nonlinear restoring force model is proposed to simulate the support’s working state during large earthquakes. Then the influences of the deformation of foundation and the material nonlinearity of piers on seismic responses of the bridge are investigated.(2) Based on the comparative analysis of the seismic response, it is indicated that the pounding has negative effect on structural seismic reliability.(3) The influences of some parameters such as seismic waves, parameters of pounding element, initial gap at expansion joints and ratio of pier height on seismic pounding responses are investigated.(4) By applying both train braking force and earthquake force to the bridge, the influences of train braking force on seismic pounding responses are investigated. The results show that train braking force will intensify the destructive effect of the earthquake. The maximum pounding force and collision times also increase substantially. So it should be considered in the seismic design of high speed railway bridges.