The Response Of Buffeting And Flutter Vibration Analysis Of Long-span Cable-stayed Bridge

As we know, the aim of wind induced vibration analyses for a long span cable-stayed bridge is to study its aerodynamic and aerostatic stability and to find its buffeting responses so as to avoid wind instability and to ensure the buffeting amplitude within a permissive range for structural safety and amenity.In this paper, the status quo is reviewed about the research on buffeting and flutter vibration of the long-span cable-stayed bridge at the first place, and the last and the most a furtherer search is done to resolve the problems and shortcomings in the time domain analysis. Based on the present theory on buffeting and flutter vibration, establish 3-D finite element and analyze flutter and buffeting responses for Ma An Shan Bridge.And accomplishes the full range nonlinear aerostatic instability program. Both geometric nonlinearity and wind loads are considered in this method. A program based on ANSYS is developed.The dissertation is mainly focused on the following aspects:1.The brief introduction of the bridge, the research issues of bridge anti-wind, the basic analysis theories of static forces and buffeting of bridge are all presented briefly.2.The characteristics of wind environment in the bridge site are studied primarily. The fundamental wind speed in bridge site is identified according to different ways, such as: statistic, codes, etc. The characteristic parameters of wind in the site are also given.3.The structural dynamic characteristics of the bridge are analyzed. The FE model of the structure, section and dynamic characteristics are presented briefly,and the static wind response of the bridge is analyzed.4.The paper proposes the modified increment and inner-outer iteration method, and accomplishes the full range nonlinear aerostatic instability program. Both geometric nonlinearity and wind loads are considered in this method. A program based on ANSYS is developed. Using the program, the configuration and mechanism of The Bridge's aerostatic instability are discussed.5.The simulation of fluctuating wind field of a long-span cable -stayed bridge is carried out by Matlab program in this paper. The nonlinear buffeting analysis and linear buffeting analysis in time domain of the bridge done. The buffeting responses are reviewed by the nonlinear buffet force acting on bridge surface of the bridge.6.The analysis results of response of static wind and buffeting in reasonable molding stage are gathered and compared. Some useful conclusions in this research are given.