Influence of near-fault ground motion characteristics on the seismic response of cable-stayed bridges

Abstract

Observations from several earthquakes indicate that near-fault (NF) ground motions have a significant influence on the seismic response of structures. However, existing studies have only discussed the influence of a certain NF characteristic on the seismic response, rather than systematically discussing and comparing the influence of different NF characteristics. Furthermore, current research is only suitable for a specific structure while the influence of NF characteristics on structures with different dynamic characteristics has not been revealed. As an important lifeline project, the safety of a cable-stayed bridge (CSB) during earthquakes is of great concern. Therefore, this paper investigates the influence of NF ground motions on the seismic response of CSB. Firstly, three major characteristics (i.e., the hanging wall effect, rupture directivity effect and high velocity pulse) of NF ground motions are analyzed using NF records of the Chi–Chi earthquake. Secondly, a finite element (FEM) model for modeling a prototype CSB is developed and benchmarked. Then, the seismic responses of the prototype CSB subjected to NF ground motions with different characteristics are analyzed using the benchmarked FEM model. The analyses show that hanging wall effect, rupture directivity effect, and high velocity pulse affect the seismic demand of the CSB to varying degrees. Furthermore, the influences of NF characteristics on the displacement response of CSBs with different fundamental periods are investigated using SDOF systems. The analysis results show that different NF characteristics have various influences on the displacement response of CSBs with different fundamental periods.