An extended multiple-support response spectrum method incorporating fluid-structure interaction for seismic analysis of deep-water bridges

Abstract

The effects of ground motion spatial variability (GMSV) or fluid-structure interaction (FSI) on the seismic responses of deep-water bridges have been extensively examined. However, there are few studies on the seismic performance of bridges considering GMSV and FSI effects simultaneously. In this study, the original multiple-support response spectrum (MSRS) method is extended to consider FSI effect for seismic analysis of deep-water bridges. The solution of hydrodynamic pressure on a pier is obtained using the radiation wave theory, and the FSI-MSRS formulation is derived according to the random vibration theory. The influence of FSI effect on the related coefficients is analyzed. A five-span steel-concrete continuous beam bridge is adopted to conduct the numerical simulations. Different load conditions are designed to investigate the variation of the bridge responses when considering the GMSV and FSI effects. The results indicate that the incoherence effect and wave passage effect decrease the bridge responses with a maximum percentage of 86%, while the FSI effect increases the responses with a maximum percentage of 26%. The GMSV and FSI effects should be included in the seismic design of deep-water bridges.