Research Of Dynamic Characteris-Tics And Asesmic Behavior For Long-Span Cable-Stayed Bridge

In recent years, earthquake disasters occurred frequently and caused a serious1-oss of life and property. In the effects of earthquake, bridges which are the most i-mportant transportation lifeline systems are also destroyed. Therefore,the co-rrect and effeetive designs of earthquake resistance are important to the safety of cable-stayed bridges.This thesis based on the engineering background of Cable-Stayed Bridge in Zhengzhou city.The example established the three dimensional finite element model of the whole bridge by using the finite element software MIDAS.The dynamic charac teristics and seismic performance of the bridge were studied by using linear response spectrum method and nonlinear time-history method.Thesis estimated the safety of the structure and obtained some valuable conclusions. The following aspects were studied in this thesis:(1) Firstly, introduced the development of cable-stayed bridge status at homeland and abroad, seismic research status and seismic analysis method of long-span bridges.(2) According to the dynamics theory, established finite element models and extr acted the top ten modes, and analysed the dynamic characteristics of the models.(3) Linear response spectrum method and nonlinear time-history method was use d to analysed the stractual seismic performance. The results showed that the towers a ndthe main beam of the bridge have a smaller internalforces under the designing seis mic loading, the second main-pier of the bridge controled seismic design. By selected reasonable cross-section and reasonable reinforcement the bridge met the requirements of section bearing capacity and had a largesafety margin.(4) Conclude of the study, the results draw several valuable conclusions and the author put forward some suggestions.