Seismic Responses Analysis Of Long-span Hybrid Girder Single Tower Cable-stayed Bridge And Study On The Seismic Measure

Hybrid girder cable-stayed bridge has unique structural feature, moreover it is the one of the developmental direction of long-span cable-stayed bridge in the future. The long-span cable-stayed bridge is usually a pivotal project for transportation. Once it is damaged in the earthquake, it will result in huge economic losses. Therefore anti-seismic analyzing the structures of long-span cable-stayed bridges and taking reasonable measures to prevent effectively earthquake have great social and economic significance. In this paper, I based the analysis of seismic response and anti-seismic measures of hybrid girder cable-stayed bridge on Guangzhou DongSha Bridge.At first ,this paper based on finite element theory, applied the finite element program Midas/civil to build the DongSha Bridge space dynamic calculation model, analyzed the dynamic characteristics, compared the bridges with the same span and the same parameters of without Auxiliary piers and came to a conclusion that the vibration frequency of the single tower hybrid girder cable-stayed bridge with auxiliary piers is higher than the same type of without auxiliary piers single tower hybrid girder cable-stayed bridge,and vibrational mode of the side direction bending and the vertical bending appear relatively late,and the structural stability better.Secondly, long-span cable-stayed bridge was made the seismic response spectrum analysis and the dynamic response time histories analysis, dentally analyzed the response feature of the bridge in different seismic input, and both methods were compared, reached the results which is greatly different from the two analysis,particularly in the more lateral of the transverse input. so we should pay attention when designing.Then, based on the above characteristics of the earthquake analysis and proposed the seismic isolation program to transverse viscous dampers are set between the piers and the girder. With finite element program Midas/civil, and analyzed the damped energy-dissipated earthquake-reduction of Guangzhou DongSha bridge.It's concluded that the use of viscous dampers can drastically reduce transverse displacements,velocities and accelerations on the deck of the long-span cable-stayed bridge. It's also concluded that forces in piers can be coordinated and forces induced in piers,the tower and the girder are reduced,too.Finally,In this paper,the main design parameters are described.The effect of damping coefficient and celocity exponents on the seismic response of the structure,maximum displacements and forces in the devices and earthquake– redu ction effectiveness of viscous dampers are studied.Conclusions obtained can be referenced when having the earthquake-reduction design of long-span cable-stayed bridge.At last,based on the results obtained,some suggestions about the design of viscous dampers in the long-span cable-stayed bridge are presented.There laws can be used as the basis of seismic design of the GuangZhou DongSha Bridge and is useful for directing seismic response analysis of such kind bridge.