Seismic Response And Shock Absorption Research Of Long-span Hybrid Beam Cable-stayed Bridge

During an earthquake， roads and bridges will be broken, and traffic will bedestroyed seriously. It will be difficult in rescue work after the earthquake, causemore severe loss of life and economic. The long-span hybrid beam cable-stayedbridge is widely used and has excellent performance. Seismic study on this type ofcable-stayed bridge has important guiding significance for the design andconstruction of the bridge. Yangpu Bridge is a hybrid beam cable-stayed bridge,，themain span is460meters long，and the geological conditions are not ideal，which arelocated in coastal waters. The main contents in the thesis based on this bridge asfollows：(1)The development course of hybrid cable-stayed bridge and the presentsituation of study on earthquake-reduction design at home and abroad are discussed.according to a long-span hybrid beam cable-stayed bridge－Yangpu Bridge，threedimensional finite element models of this bridge with and without pile-soil interactionare established by using finite element analysis software-Midas/civil2010. Freevibration characteristics of these two models are analyzed and compared.(2) Discuss the advantages and disadvantages of existing seismic dynamicanalysis methods. Both the response spectrum method and time-history method areapplied to study the seismic response of models with and without pile-soilinteraction， and the results from these two methods are compared and discussedthoroughly.(3)This paper uses viscous dampers for earthquake-reduction design，studies theseismic dynamic response of hybrid girder cable-stayed bridge with fluid viscousdampers. Furthermore，the parameter of the damper is optimized，a set of optimalparameter of viscous dampers is proposed. Two kinds of damper layout scheme aregiven：Dampers are placed between the main towers and the main beam；Dampers areplaced in auxiliary piers and the main towers. And make a comparing for the twomethods. The analysis indicates that the viscous damper with rational parameters mayreduce the Seismic displacement significantly，and reduce internal forces in the sametime. The design can improve the cable-stayed bridge seismic capacity anddurability，which agrees with the idea of earthquake-reduction design，and can beused as reference for other bridges seismic analysis and earthquake-reduction design.