Effects of Near-Fault Pulse-Like Ground Motions and Pulse Parameters on a High-Speed Railway Long-Span Arch Bridge–Track System

Abstract

Arch bridges are increasingly used for high-speed railway (HSR) bridges because of their superior structural properties and ability to span extensive distances. However, their seismic behavior under near-fault pulse-like records remains inadequately investigated. This paper presents a refined nonlinear finite-element model (FEM) of a long-span HSR arch bridge, developed from existing shaking table tests. According to the site characteristics of the bridge, seven fling-step pulse records, seven forward-directivity pulse records, and seven nonpulse records are selected, with their peak ground accelerations scaled to a design basic earthquake level of 0.2g, to examine the impact of various pulse types on structural seismic responses. Additionally, artificial pulse-like records with varying pulse characteristics are simulated using the record-decomposition incorporation method to analyze the effects of pulse amplitudes, pulse periods, and the number of pulse peaks on structural seismic responses. The results show that the FEM effectively captures structural response characteristics under pulse-like records. Fling-step pulse records induce a more significant seismic response compared with forward-directivity pulse records. Structural seismic responses increase with the pulse amplitude. In fling-step pulse records, structural seismic responses also increase with the pulse period, whereas no clear correlation with the pulse period is observed in forward-directivity pulse records. Moreover, pulse-like records with an odd number of pulse peaks provoke a greater seismic response in the bridge than those with an even number of peaks.