Critical Issues in Seismic Design of North Branch Main Bridge of Xiamen-Zhangzhou Cross-Sea Bridge

The main bridge in North Branch of Xiamen-Zhangzhou Cross-Sea Bridge is a 5-span continuous steel box girder double-pylon cable-stayed bridge with 780m main span and the basic earthquake intensity at the bridge site is VII. In order to ensure the safety of the bridge under earthquake, the special seismic design of the bridge must be carried out. In this paper, the critical issues in seismic design of the bridge are studied. Firstly, the seismic fortification objectives and criteria are determined, then the influence of seismic excitation method, pylon(pier)-girder connection type, pile-soil interaction, liquefaction and scouring on the bridge is analyzed, and finally the optimization design of the damper is conducted through the sensitivity analysis of parameters. This paper provides the general idea of the seismic design of long-span cable-stayed bridges, which can be adopted by the seismic design of similar bridges.