Seismic Response Analysis of Cable-Stayed Bridges

Abstract

For floating system cable-stayed bridge, the longitudinal displacement of stiffening girder and moments of towers are very large when strong earthquake happens. Too large displacement of stiffening girder leads to collision between girders of the main bridge and the approaches. Using spatial finite element model and time history analysis method, the seismic responses of cable-stayed bridge are studied considering the elasto-plastic effects. The results show that the displacement of stiffening girder is very large when no seismic reduction measures are adopted. The viscous dampers installed between the stiffening girder and towers can efficiently reduce seismic responses of the cable-stayed bridge. Especially, the displacement of stiffening girder can be controlled well to meet the design requirement. Using the optimum parameters of damper, the height of pier under tower and intermediate supports in side span on seismic responses are studied in detail. The longitudinal displacement of stiffening girder increases with the pier height increasing. The intermediate supports in side span are benefit for seismic reduction.