Research On Temperature Influence And Dynamic Characteristics Of Wide Cable-Stayed Bridge With Double Cable Planes

Cable-stayed bridge is widely used in long-span bridge construction because of its strong spanning ability and light beam structure.The cable-stayed bridge is easily affected by many factors such as environment and load in the operation stage,which leads to the deformation and internal force redistribution of the structure,which is different from the initial state of the bridge.On the one hand,the cable-stayed bridge will experience the influence of annual temperature difference and sunshine temperature difference after the completion of the bridge.No matter under the influence of annual temperature difference or sunshine temperature difference,the structure of the cable-stayed bridge will lag behind the internal temperature change due to the poor thermal conductivity of concrete,which will make the cable-stayed bridge structure produce large temperature difference effect and temperature stress,thus having a great influence on the structural stress and deformation of the cable-stayed bridge.In some states,the influence of temperature effect on the internal force of cable-stayed bridge structure sometimes even exceeds the influence of dead load.On the other hand,due to the change of some structural parameters of the cable-stayed bridge during the long-term operation(such as the decrease of the cross-sectional area and the change of the elastic modulus due to the damage of the cable,the change of the second-stage dead load caused by the replacement of the bridge deck,the sudden fracture of the cable due to fatigue,etc.),the static and dynamic performance of the cable-stayed bridge will change.Therefore,it is necessary to analyze the temperature effect and dynamic characteristics of long-span cablestayed bridges under operating conditions.In this paper,the temperature effect and the influence of structural parameters on the dynamic characteristics of the bridge are studied in the operation stage of the Wuhan West Fourth Ring Hanjiang Bridge.In this paper,the finite element dynamic analysis model of the wide double-tower double-cable-plane cable-stayed bridge is established by using the ridge beam space finite element bar system model.On this basis,the temperature effect and dynamic characteristics are analyzed.The main research work is as follows:(1)According to the design parameters of Hanjiang Bridge and the test data in recent years,the spatial finite element model of the bridge is established by using finite software.(2)The linear change of the main girder of the bridge under the annual temperature difference is studied,and the deflection curve of the main girder under the annual temperature difference is obtained,which is compared with the measured data(winter and summer).At the same time,the paper also studied the deviation of the bridge tower under the annual temperature difference,and compared with the field measurement results.(3)According to the established finite element analysis model of cable-stayed bridge,and based on the design and measured parameters,the dynamic characteristics of the bridge are analyzed,and the influence on the dynamic characteristics of the bridge caused by the reduction of the cross-sectional area due to the damage of the stay cable,the change of the elastic modulus,the change of the secondary dead load caused by the replacement of the bridge deck,and the sudden fracture of the stay cable due to fatigue are discussed.