Sensitivity Analysis Of Seismic Dynamic Response Of Long Span Cable Stayed Bridge

China is located between two active seismic zones,and earthquake disasters occur frequently.As an important hub in the transportation network,if the bridge is damaged in the earthquake,it will not only cause huge economic losses,but also increase the difficulty of post disaster rescue.Therefore,the research on seismic performance of cable-stayed bridge has been a hot topic in academic and engineering circles.Taking the long-span double tower cable-stayed bridge as the research object,this paper studies the sensitivity of random variable parameters to the cable-stayed bridge under earthquake,and analyzes the influence of damper parameters on the dynamic response of the cable-stayed bridge.The main contents of this paper are as follows:(1)The present situation of seismic research and sensitivity analysis of cable-stayed bridges are introduced.The existing seismic theory of bridges is summarized,and the theoretical basis of seismic response analysis method and sensitivity analysis method is elaborated.The theory and method of the technology of reducing and isolating are introduced,and the mechanical model and principle of viscous damper are described in detail.(2)According to the engineering design data of the cable-stayed bridge,the finite element model of the cable-stayed bridge is established by MIDAS /civil 2019.The dynamic characteristics of the cable-stayed bridge considering the pile-soil interaction and not considering the pile-soil interaction are analyzed.The dynamic characteristics of the cable-stayed bridge are calculated,and the results are analyzed and summarized.(3)According to the site conditions and period conditions of the bridge,the seismic wave is selected for the dynamic time history analysis of the cable-stayed bridge,and the rationality of the seismic wave of the cable-stayed bridge is verified according to the requirements.(4)FOSM and Tornado graph method are used to analyze the random variables that affect the dynamic response of cable-stayed bridge under earthquake action.The random variables are selected: ground motion parameter PGA,material properties(elastic modulus of steel girder,elastic modulus of stay cable and concrete),damper parameters(damping coefficient and velocity index)and damping ratio of bridge structure.The influence of each random variable on the sensitivity of seismic dynamic response of cable-stayed bridge is obtained and sorted according to the influence degree.(5)This paper analyzes the influence of the parameter change of viscous damper on the dynamic response of cable-stayed bridge,analyzes the cable-stayed bridge with viscous damper,and studies the influence of the parameter change of damper on the damping effect of long-span cable-stayed bridge.Through the research on the parameters of viscous damper,the optimal parameters of viscous damper are obtained.