Seismic Behavior Research For Long Span Cable-stayed Bridges With Steel-concrete Composite Grider

When earthquake happens,traffic will be disrupted,and seriously impact the stability of society.It is difficult to rescue after the earthquake,also can cause more severe loss of life and economic.The long-span hybrid beam cable-stayed bridge is widely used and has excellent performance.Seismic study on this type of cable-stayed bridge has important guiding significance for the design and construction of the bridge.Yuekou hanjiang large bridge is a hybrid beam cable-stayed bridge which main span is as long as 474.6m.Based on Yuekou hanjiang large bridge,analysis its response of seismic by two methods of response spectrum and time-history analysis,and discussed the damping measures in this dissertation,the response analysis spectrum and dynamic time-history analysis are carried out,and the vibration mitigation control is also studied.The research conclusions are as follows:(1)The development of composite beam cable-stayed bridge and its research status in all over the world are discussed,two kinds of finite element model whose are piled and unpiled were established by using three-dimensional finite element modeling software,and their dynamic characteristics were analysised,it is found that the natural vibration period of piled modeling is larger than one of unpiled modeling.(2)Analysised dynamic response of the selected key nodes and sections of structure under the impact of earthquake according to two methods which are dynamic response and time-history analysis,and the consequences of theirs were compared.The conclusions reveal that we should use these two methods to calculate the earthquake response of bridge.(3)The impact of traveling wave to seismic response of structure under the longitudinal and vertical earthquake is researched,it can be seen that traveling wave can increase the dynamic response of the selected key nodes and sections of sttucture.(4)The different impacts of parameter values in viscous dampers to dynamic response of hybrid beam cable-stayed bridge were studied,and the optimal parameters for bridge were selected.As the conclusion of research,the best damper parameter is C=4000,α=0.3.