The Anti-Seismic Analysis Of The Railway Low Tower Cable-Stayed Bridge

Low-pylon cable-stayed bridge is a novel type of combination bridge between continuous beam bridge and cable-stayed bridge. This bridge type has been widely used by countries in the world because of its good force performance, beautiful shape, reasonable ratio of performance to price, flexible span arrangement and easy construction. In China, this bridge type has been frequently applied to highway construction, but rarely to railway construction. Therefore, it is a new attempt to apply low-pylon cable-stayed bridge to a super large railway bridge from Beijing to Shanghai.Analyses on seismic response of this super large railway bridge and shear performance of its pier and main tower were performed based on researches on seismic responses of long-span continuous beam bridges, cable-stayed bridge and highway low-pylon cable-stayed bridge. Based on the model of this bridge built by a general finite element software MIDAS/Civil, the following contents were studied:Dynamic characteristics of this bridge including vibration frequency and mode were gained through dynamic analyses on the model of the bridge. Then response spectrum analysis and elastic and elastic-plastic time-history response analysis of this model were performed under rare and frequent earthquake. Through comparing the results under rare earthquake with that under frequent earthquake, the internal force in the interface of seismic weak position of the model was chosen in order to perform intensity checking computations. Finally, shear calculations on pier and main tower of this bridge were performed according to different methods in three specifications, and then the results were compared with that calculated by the finite element software MIDAS/Civil.All the results indicated that the seismic design met the requirements in specification for seismic design of railway engineering. This study on seismic analysis of low-pylon cable-stayed bridge will be helpful to the widely use of low-pylon cable-stayed bridge in railway construction.