Seismic Damage Control of Bridge Bents Retrofitted with Structural Fuse Under Near-fault Pulse-type Ground Motions

Buckling restrained braces(BRBs)retrofitted to a double-column bridge bents as sacrificial components could enhance the lateral seismic performance of bridge near the fault area,based on the structural fuse concept.A single-function analytical model was used to simulate a group of low-frequency pulse components with moment magnitude and fault distance as the main parameters,according to the characteristics of near-fault pulse-type ground motions.The high-frequency components of strong motion record were obtained by time-frequency filtering and the low-frequency pulse components were superimposed to generate the input ground motion.The bents of an ordinary highway bridge were used as a reference for a dynamic analysis model and the effects of the BRB layout scheme(inverted-V,diagonal and toggle type),moment magnitude,fault distance,and the number of velocity pulses on the seismic performance of the bents were studied using a nonlinear time history analysis.The results show that installing BRBs can improve the seismic performance of bridge bents and reduce seismic damage.Furthermore,the energy dissipation capacity of toggle BRB systems is stronger than that of traditional inverted-V and diagonal BRB systems,particularly under small displacements.