The Parametric Vibration Of The Chongqiong Fuling Wujiang Extra-large Bridge

Cable-stayed was a kind of very flexible structure components. Usually had the character of small damping coefficient, and bore a variety of dynamic load, such as:traffic, wind, pedestrians and earthquake.Components in cable-stayed bridge under the influence of these external factors were highly susceptible to vibration, in practice due to the vibration caused by the lasso engineering accident was also common occurrence. November 2012, significantly cable-bridge coupled vibration happened to wujiang bridge of Fu Feng Stone Highway. Som e researches and analysis are necessary to providing theoretical basis for the control of Lasso vibration,which need verifying whether it is parametric vibration and analysing the main vi bration of the cable. In this paper, the research mainly included the following:In this paper, for the vibration of the stay cables of the reported at home and abroad,and expounded in detail the research situation.Introduced the commonly used several kinds of nonlinear cable curve equation:elastic catenaries equation, taking into account the string to the gravity component parabolic equation, the string to the gravity of parabolic equation. To ideal assumption of lasso, established the cable-stayed nonlinear inherent vibration model and axial excitation, cable in-plane vibration parameters of the model, under the coupled action of cable-stayed cable-bridge in-plane vibration model parameters. By using Hamilton’s principle for the corresponding nonlinear vibration equation of the first model are applied to solve the equation using the method of L P and after two model equation using multi-scale method. In Chongqing Fufengshi high-speed Wujiang river extra-large bridge as the engineering background, on the parameters of the suspension vibration nonlinear equations by using runge-kutta numerical analysis method,study the vibration characteristics and influencing factors.The dynamic model of Chongqing Fufengfhi high-speed Wujiang river extra-large bridge was established by applying the Midas, the first 30 order vibration frequency and vibration modal were obtained.Combined natural vibration frequency has been to analysis of vibration of stay cables, it was concluded that the bridge is given priority to with primary resonance, lasso only FDB 19 resonant parameters.Combined the cable-bridge coupled parametric of FDB 19 cable were analyzed, and studded the frequency ratio, deck initial excitation, cable damping ratio, damping ratio deck, the impact force on the cable-stayed cable parameter vibration.