Effects of near-fault pulse-type ground motion on train-track-bridge coupled system with nonlinear supports

Abstract Researches have revealed that Under the excitations of near-fault pulse-type (NFPT) earthquakes, the elastic-plastic deformation occurs on bridge structures, which leads to significant challenge of high-speed railway running safety performance. This paper is mainly focuses on the dynamic responses of train-track-bridge coupled system (TTBCS) under NFPT ground motions. With nonlinearities of supports being modelled in the TTBC model (TTBCM), the comparison between linear model and nonlinear model reveals the necessity of nonlinearity when conducting TTBCS numerical simulation under NFPT ground motions. Moreover, the dynamic responses of TTBCS arisen by NFPT ground motions are investigated and discussed on the basis of pulse parameters analysis, and relevant conclusions about potential relationship between pulse parameters and running train are given. Based on parameters analysis, a multiple-parameter regression between spectral intensity (SI) and pulse parameters is conducted, with the combination of running safety assessment (RSA) criteria including Nadal, wheel unloading, and wheel lift, suggestion from RSA perspective under NFPT ground motions are proposed as well.