Seismic performance comparison of different station‑bridge combination systems under transverse earthquakes

In order to compare the seismic performance of different station-bridge combination systems under transverse seismic ac tion， this paper takes an actual station-bridge separation system as the research object， designs a station-bridge integrated system combined with the actual situation， considers the nonlinear effect of bridge piers and supports， and the nonlinear sliding friction ef fect between expanded foundation， gravel cushion and metro station roof. A three-dimensional nonlinear dynamic model is estab lished by using the finite element software MIDAS/Civil， and the dynamic response and pier damage of the composite system of two different stations and bridges under the cross-bridge seismic input are studied. The results show that under the unusual seismic lateral input， compared with the station-bridge integrated system， the station-bridge separation system can prolong the structural period and effectively reduce the dynamic response of the pier bottom and the supporting column of metro station. For the two com bined station-bridge systems， the internal force response of the supporting column corresponding to the position of the pier is great er than that of other ordinary supporting columns. Under the lateral seismic input of the rare earthquake， compared with the station bridge integrated system， the station-bridge separation system appears later in the plastic state， the final damage degree is lighter， the time of the support entering the nonlinear stage is later， and the overall deformation of the bridge pier is smaller. The seismic performance of the station and bridge separation system is better under the transverse earthquake action. However， in the actual project， attention should be paid to the increase of internal force caused by the transverse frame effect of the subway support col umn and the limit of the bridge foundation slip.