Seismic response of high-speed railway simple-supported girder track-bridge system considering spatial effect at near-fault region

High-speed railway are mostly long-line structures stretching for several kilometers, and the seismic response analysis of individual stations cannot accurately determine the overall safety of the structure. In this study, 53 stations with rupture distances less than 50 km were selected from the Taiwan Chichi earthquake, and they were divided into three regions according to the rupture location. The seismic response and spatial distribution characteristics of High-Speed Railway Track-Bridge System (HSRTBS) under the original ground motion as well as the amplitude scaling ground motion of each station were investigated. The results showed that: (1) Under the original ground motion, the average seismic response of HSRTBS in the middle region (MR) is the largest, while the one in the forward region (FR) is the smallest. The displacements and internal forces of the structural components follow a logarithmic relation with Rrup/a (ratio of rupture distance to peak acceleration) and they tend to be stable when Rrup/a is larger than 100 degrees (2) There is a correlation between the seismic response of HSRTBS and the fault angle. In FR and MR, the seismic response of the HSRTBS is the smallest at a fault angle 90 degrees, while, at the backward region (BR) the minimum response of the HSRTBS is noted for fault angle 45 degrees.