Effect of Hydrodynamic Pressure on Seismic Response for Seismically Isolated Girder Bridge in Deep Water

The seismic action will cause the radiation wave movement of the water body around bridge structure in deep water, which will exert hydrodynamic pressure on the underwater structure and affect the dynamic response of the bridge. In this paper, a continuous girder bridge across sea is taken as an example to study the effect of hydrodynamic pressure on seismic response for deep-water bridges with different seismic isolation systems. The seismic response analysis method of deep-water bridges under hydrodynamic pressure is firstly established, and the dynamic response analyses of the bridge with friction pendulum system and cable-sliding friction bearing system are carried out, respectively. The results show that the hydrodynamic pressure increases the seismic response of deep-water bridges. Under friction pendulum system, the influence of hydrodynamic pressure on the longitudinal internal force of each pier and pile is greater than that on the transverse internal force, and the influence on the internal force of the pile top is greater than that of the pier bottom. The influence of hydrodynamic pressure on seismic response under cable-sliding friction bearing system is obviously less than that under friction pendulum, which shows the superiority of cable-sliding friction bearing in seismic design of deep-water bridges.