The Seismic Response Numerical Analysis On Cable-stayed Bridge In Deep Water

Large span bridges are widely used in our country. With a variety of bridges crossing sea,river and reservoir, lots of deep-water bridges are in building or prepared to construct in our country.While China is a country which earthquakes are common. once cable-stayed bridge is damaged in the earthquake disaster, it would cause great losses.Under earthquake action, the vibration of the pier can cause radiation wave motion of fluid around the structure, and then radiation wave motion act on pier. That is the interaction between pier and water.The dynamic characteristics and the dynamic responses of the structures will be changed due to the effects of the interaction. However, the effects of pier-water interaction induced by the earthquake on the deep water structures, such as underwater foundation of large span bridges have received relatively little attention in exiting literature. The numerical simulation methods research of bridges in deep water is even less.At the urgent request of anti-earthquake in deep-water bridge structure, the research on seismic performance of deep-water bridge in domestic and foreign is not comprehensive and mature, and it is almost blank in the numerical simulation methods research. Therefore, taking Yun-Yang Chang Jiang River bridge as an engineering example, this paper intends to consider the interaction of pier-water coupling theory based on the basic theory of the seismic response analysis. According to the newly issued "highway bridge aseismic design rules ",it has the seismic time history analysis. By using ANSYS software to establish a finite element static calculation model of Yun-Yang Chang Jiang River bridge. The upper-structure takes three-dimensional simulation modeling. Piers and the liquid media around the pier take entity modeling. Different conditions of dynamic analysis models are created depending on the depth of water. The dynamic properties were calculated for different models, then Calculation results are analyzed and compared. Considering the combination of vertical seismic and vertical seismic input, analyse seismic response of cable-stayed bridge in deep water. The effects of pier-water coupled vibration for seismic response of bridges are analyzed and compared. The results show, that the vibration characteristics of cable-stayed bridge are affected by fluid medium surrounding. Bridge natural frequency decreases with increasing water depth; The displacement and bending moment of the main beam, the moment in pier bottom are in a substantial increase because of pier-water coupled vibration. Fluid-structure interaction must be taken into account for the seismic response analysis of cable-stayed bridge in the deep water. The papers shows that the effects of pier-water coupled vibration must be considered in practical engineering calculations, ignoring the impact of this factor will lead to unsafe calculations.It is expected to give some references for practical seismic design of similar bridges.