Study on the dynamic response correction factor of a coupled high-speed train–track–bridge system under near-fault earthquakes

The extension of high-speed railway construction to earthquake-prone regions has significantly increased the probability of trains encountering an earthquake while running on a bridge. Therefore, it is urgent to explore the applicability of the additional static quality method (ASQM) of train load simulation specified in the Code for seismic design of railway engineering. Based on comprehensively considering the uncertainty of ground motions, this paper builds spatial analysis models for train–track–bridge systems based on ASQM and the moving spring-mass column method (MSMCM), respectively. Next, it calculates the seismic responses of structures under near-fault earthquakes using a large number of samples and evaluates the applicability of ASQM through large-sample analysis. As the analysis results revealed, the statistical characteristics of over-standard ratios tend to stabilize with the increase of sample size. Under near-fault earthquakes, bearing deformation, pier shear strength, and maximum ductility all have high over-standard ratios. The seismic checking computations of bridge structures based on ASQM have failed to meet the applicability requirements, and the calculation results of the seismic responses of track structures are severely distorted. Introducing a reasonable dynamic response correction factor based on ASQM helps to effectively lower over-standard ratios, thus meeting the applicability requirements for the seismic checking computations of bridges.