Seismic Response And Seismic Isolation Analysis Of Cable-stayed Bridges In Deep Reservoir Area

With the increase in transportation investment in Southwest of China,more and more bridges inevitably cross the reservoir area of hydropower stations to form deep-water,highpier and large-span bridges.The construction of deep-water bridges in high-intensity areas puts forward new requirements for the seismic fortification of bridges.The study of fluidstructure coupling effects under seismic excitation has become the focus and hotspot of deep-water bridge seismic response research.In this paper,a cable-stayed bridge with a low-pile cap structure in a reservoir area in southwest of China is selected as the research object.The finite element software Adina and ANSYS are used to calculate and analyze the seismic response of the tower column and the completed bridge under multi-conditions.Discuss the influence of deep water on the dynamic response of cable-stayed bridges.The main research work of this paper is as follows:(1)Based on the current research status of deep water Bridges,the domestic and foreign conclusions of deep water Bridges under seismic action and main methods are introduced.The relevant standards and simplification methods are sorted out and summarized.The theoretical basis of finite element simulation based on Potential-FluidBased-Element(PFBE)is also introduced.(2)Using Adina to analyze the dynamic characteristics and dynamic response of single tower components under different working conditions such as different water depths and different water areas.Analyze the dynamic characteristics and dynamic response change laws of single tower components in different water depths and water areas.(3)Using ANSYS to establish a single-tower beam element model,and using two additional mass methods of 2020 code and Yang-Wanli simplified formula to analyze the dynamic characteristics and dynamic response analysis of single-tower components at a water depth of 75 m,and compare the calculation structure of Adina single-tower in the previous chapter Conducted comparison verification.(4)Adina was used to establish a simplified solid model of the whole bridge to analyze the dynamic characteristics of the whole bridge under waterless conditions and full reservoir water level.At the same time,for the subsequent time history calculation of the full bridge,in order to improve the calculation efficiency,ANSYS was used to compare and verify the dynamic characteristics and dynamic response of the beam element full bridge model based on the additional mass method.(5)For the whole bridge model with beam elements using the additional mass method,the dynamic response of the deep water bridge at different water levels is analyzed by ignoring and considering the nonlinearity of the support,and the influence rlue of the damper and other isolation devices on the seismic response of the whole bridge under the consideration of the dynamic water effect is obtained.