Fragility Analysis of Pier-Tower-Girder Fixed Cable-Stayed Bridge Subjected to Near‐Fault and Far‐Fault Ground Motions

The cable-stayed bridge (CSB) with a tower-pier-beam fixed system has gained wide recognition due to its aesthetically pleasing design, excellent wind resistance, convenient construction, and relatively lower cost. A pier-tower-girder fixed cable-stayed bridge (CSB) is constructed using the OpenSees nonlinear finite element model, and the bridge tower response under near-field (NF-GMs) and far-field ground motions (FF-GMs) is analyzed. A probabilistic seismic demand model (PSDM) is developed for cable-stayed bridge tower subjected to both NF-GMs and FF-GMs, using the peak ground velocity (PGV) and peak ground acceleration (PGA). The CSB tower’s fragility curves for each section are obtained, and the fragility median points of each pylon section under various seismic excitations with slight damage are further contrasted. The study indicates that utilizing PGA as the measure of ground motion intensity, the lower portion of the bridge tower experiences the initial damage when subjected to GMs. Furthermore, in comparison to FF-GMs, CSB tower demonstrate higher vulnerability to damage when subjected to NF-GMs.