Three-dimensional finite model for Tonghai road cable-stayed bridge on the Huangshui River in Xi′ning is established in this paper.The dynamic responses of the bridge with semi-floating systems is studied with or without the consideration of pile-soil interaction.The influence of pile-soil interaction on the dynamic responses of bridge structure is analyzed.The structural rigidity and boundary conditions of the bridge are also examined in this paper.On the basis of the above analysis result

the dynamic responses of bridge structure is studied by using seismic history analysis method.The influence of cable sag and bracket as well as the pile-soil interaction are also considered in this model.The seismic performance of structure is analyzed and some guiding principles are proposed for seismic design of the bridge.The study can provide valuable engineering experience and efficient method for seismic response analysis of cable-stayed bridge with single tower

single cable and wide bridge deck.