Transverse seismic performance of small and medium-span simply supported bridges with buffered block seismic damping systems

Abstract

To improve the transverse seismic performance of small and medium-span simply supported bridges and ensure their post-earthquake traffic capacity, this paper proposes the Buffered Block Seismic Damping System (BBSDS). The BBSDS is designed to dissipate energy and limit displacements through a slip-and-deformation mechanism. The mechanical properties of the BBSDS are validated through theoretical analysis and numerical simulations. Additionally, a simplified mechanical model is developed. Nonlinear analysis models of simply supported bridges are established for four working conditions: without shear keys, with concrete shear keys, with steel shear keys, and with BBSDS. The base shear, base moment, relative displacement between the pier and girder, residual displacement, and bearing displacement are compared. The results show that a simply supported bridge with BBSDS effectively limits the displacement of the girder without significantly increasing the base response of the pier. Notably, the BBSDS also reduces the residual displacement and bearing displacement, thereby mitigating bearing failure. Parametric analyses were conducted on the slip stiffness, limit stiffness, and initial gap of the BBSDS. The results indicated that an increase in slip stiffness or limit stiffness effectively reduced the residual displacement; however, it may concurrently elevate the base response of the pier. The increase in the initial gap reduced the base response of the pier, but increased the relative displacement between the pier and beam, as well as the residual displacement. The recommended range of design parameters for the BBSDS is provided.