Transverse seismic analysis of high-speed railway bridge in China based on a simplified calculation model

In seismic analyses of high-speed railway simply-supported bridges, the constraint imposed by the track structure is non-negligible. Despite its great computational efficiency, the bridge model (BM) may produce an unreasonable seismic response, because it does not consider the track structure. The bridge-track model (BTM), which considers the track structure, is very complex, and its computational efficiency for seismic analysis is low. Therefore, developing a simplified calculation model for seismic analysis of high-speed railway bridges has great practical engineering value. In this paper, the simplified bridge-track model (SBTM) for transverse seismic analysis of high-speed railway bridges is established by setting nonlinear springs between girders. These springs can accurately simulate the constraint that the track structure imposes on the bridge. Seismic analysis of a five-span high-speed railway bridge is carried out using the SBTM, and the seismic response is compared to that of BM and BTM. The results show that the seismic responses of both SBTM and BTM match well under different seismic records, which validates the calculation accuracy of SBTM. Compared with the BTM, the calculation time of the SBTM is significantly shorter. The track structure is basically in the elastic stage under frequent earthquakes, while under design earthquakes and rare earthquakes, the stiffness of the track structure will degrade.