Seismic applicability analysis of high-speed railway multi-span simply-supported bridges based on simplified model

CRTS II ballastless track is more commonly used in railway operations since it can meet the railway comfort and smoothness requirements. The effects of track constraint on the seismic response of high-speed railway simply-supported bridges can not be neglected. However, refined track structure modeling can significantly increase the computational time. Therefore, adopting a reasonably simplified model (SM) can improve computational efficiency effectively. Based on the principle of virtual work, the equivalent system is adopted instead of the track structure, and build a simplified model of bridge-track system. And on the basis of considering the randomness of the earthquake, the seismic response of the track-bridge model, the simplified model and the trackless model with different span numbers are compared, the over-capacity ratio and track constraint effect of the high-speed railway bridge-track system under the earthquake are analyzed. The analysis shows that the simplified efficiency of simplified model is up to 85% under longitudinal and transverse ground motions, and the seismic responses are in good agreement with those of the bridge-track system model; The track structure has a greater influence on the safety of the over-capacity probability (SPO) of the bridge structure under the longitudinal ground motion, particularly when the number of spans is high and ignoring the track structure may underestimate the over-capacity probability of some structures.