Based On Response Spectrum Finite Element Analysis Of Dynamic Characteristics And Seismic Response For Cable-stayed Bridge

With the rapid development of China's economy, traffic-building has also been an unprecedented amount of increase, in order to meet the demand of larger span, prestressed concrete cable-stayed bridge, one of the most popular bridge styles, has been widely used; its excellent crossing capacity and remarkable structural features make this type bridges'span increase day by day and become the leader in long-span bridges alternatives. China is the country prone to earthquakes, when the earthquake occurred; the road line became lifeline, as the bridge became the key point of the lifeline. It is the determinant to reconstruction work carried out smoothly and the rapid economy recovery whether the bridge was damaged or not, so the bridge is closely related with life. Therefore, it is vital to implement effective seismic measures and scientific researches and to establish a reasonable system of seismic structure and to grasp the seismic capacity of bridges.In this paper, on the basis of the relevant results at home and abroad, Su Tong Bridge is considered to be the practical engineering background, the analysis on the dynamic properties and seismic response of cabled-stayed bridge is the following:(1) Firstly, analyze the structure characteristics of current long span cable-stayed bridge and the design parameters and status of its development, and the status of seismic design, point out the necessity of earthquake response analysis; then the problems in cable-stayed bridges seismic response analysis are proposed and analyzed; obtain the key issues to be analyzed in this paper.(2) Followed by systematic exposition and summarizing the seismic response analysis method, response spectrum method, including its basic assumptions, the adaption scope of the analysis process and the steps, the deduction and correction to the problems of the method in details, etc.(3) At the same time, the finite element analysis software MIDAS CIVIL is used and the appropriate simplification of the cable-stayed structure is taken out to establish the spatial model as the basis of dynamic properties and seismic response analysis. On the circumstances of ignoring the interaction of pile and bridge foundation soil, the calculation of vibration characteristics of cable-stayed bridge is carried out;(4) Finally, according to the results of the bridge structure model, the vibration characteristics and modes analysis comparison is made between setting damping device and not setting the device in the cable-stayed bridge vibration. Some conclusions are drawn. Also, the response spectrum analysis is carried out under uniform excitation, the seismic response analysis effect is made, respectively, in the way of single seismic input and combined seismic input, and then it is necessary to summary the impact to the results of different seismic input direction of the span cable-stayed bridge. At last, the seismic response results comparison between having the damping device and not having damping device is executed to draw the conclusion to the damping device affecting the seismic characteristics.