Influence of Multidirectional Cable Restrainer on Seismic Fragility of a Curved Bridge

This paper presents a passive control device—multidirectional cable restrainer (MDCR)—and develops the fragility curves of a curved bridge with and without MDCR, respectively. Three-dimensional finite-element models with and without MDCR were established by OpenSees software. In order to consider ground motion uncertainty, 80 ground motion records were selected from the Pacific Earthquake Engineering Research (PEER) strong motion database. Meanwhile, the parameters of MDCR, such as initial slack and stiffness of cable and the incidence angle of the motions, were treated as random variables. The probabilistic capacity model of the pier with varying gravity force was established using the response surface method (RSM). System fragility curves of the bridge with and without MDCR were developed by Monte Carlo (MC) simulation, and the correlation of the bridge components was considered in the process of sampling. The results show that of the six intensity measures (IMs) considered, spectral acceleration at the period of 1 s (Sa10) is the optimal IM for the curved bridge prototype. In addition, piers are the least vulnerable component for the system with MDCR.