Seismic performance evaluation of large-span offshore cable-stayed bridges under non-uniform earthquake excitations including strain rate effect

Abstract

This paper presents a novel and precise seismic performance evaluation method for large-span offshore cable-stayed (LSOCS) bridge by considering the strain rate effect of RC materials and the spatial variation effect of seafloor seismic motions. Three-dimensional finite element (FE) model of a LSOCS bridge located in the southeast coast of China is constructed in the ABAQUS platform. The non-uniform ground motions at the offshore site beneath the bridge are stochastically simulated and used as seismic inputs. Moreover, a subroutine for considering the rate-dependent properties of RC materials in a fiber-based beam-column element model is developed to account for the strain rate effect of RC materials in the nonlinear time-history analysis. The numerical results indicate that seismic responses and fragilities of the LSOCS bridge are both considerably affected by the non-uniform seafloor seismic motions and strain rate effect. The seismic performance evaluation approach presented in this paper can provide vital support for earthquake resistant design of LSOCS bridges.