Nonlinear Time-history Analysis Of Seismic Response And Seismic Control Of Long-span Cable-stayed Bridges

Earthquake is a kind of natural disaster which is difficult to predict and the damage degree is very great, occurrence of the strong motion often leads to the tremendous life and property loss. As an important part of the traffic key project and the lifeline engineering, will bring great inconvenience to the resist seismic and rescue of the people when subjected to damage. Therefore, it is very necessary to conduct the comprehensive and systemic investigation on the bridge aseismic.In this dissertation, the nonlinear static and dynamic characteristic and seismic responses under uniform and non-uniform excitations of cable-stayed bridge structure are systematic studied. And the following work and achievements are included.1. Summarize the research development and status quo of the long-span bridge structures and choice and input of the earthquake ground motion.2. Deduce the equilibrium equation on the base of nonlinear FEM theory. The Eeq is used to calculate the cable sag effect; axial force-bending moment interaction in the bridge deck and towers is considered by stability founction and geometric stiff matrix. And the stability function is deduced in this analysis. About the solution method of the nonlinear equaiton,the iterative procedure with dynamic coordinate is proposed in this thesis.3. All sources of geometric nonlinearity are considered in the nonlinear static analysis and a finite element computation program is developed and debugged. Two cable-stayed bridge models with its main span of 335m and 670m respectively are analyzed. And the results of the linear and nonlinear static analysis are compared in detail, And the influence of each nonlinear resource of it are studied, which are the base of dynamic analysis.4. The nonlinear motion equations of long-span bridges subjected to the uniform and multiple-support excitations are deduced. And the mathematic solution method of them are primary analyze. The treatment of mass matrix, the stiff matrix, the damp matrix and the dynamic model of cable-stayed bridges in the analysis concluded in this research. A comprehensive study on the above mentioned two cable-stayed bridge models on the base of the theory are conducted.5. The dynamic characteristic and the seismic response of Wuhan Junshan Yangtze Bridge whose main span is 460m under uniform and non-uniform excitations are studied in this dissertation. The cable forces of it are computed using the self developed program. The results of it can have some reference meaning in the asesmic design and construction of this kind of bridges structure.6.The seismic response of the Wuhan Junshan Yangtze Bridge when using the LRB or VED of LRB+VED base is researched. The results of it can have some reference meaning in the seismic isolating of this kind of bridges structure.7. Finally, the work in this paper is summarized and some conclusions about the study are drawn, besides, the further research problems are indicated.