The Seismic Response Analysis And Seismic Study Of Cable-Stayed Bridge

Bridge is a hup for transportation system projects, an important part of the lifeline, It is important to ensure the safety of bridges in the earthquake and the normal use. In particularly,in the urban and regional earthquake disaster prevention and post-earthquake reconstruction work.JiLin LanQi Songhuajiang River bridge is a Cable-Stayed Bridge with parallel low relaxation galvanized PES7 steel cable. Two Towers and double cable planes,but the spacing of the two cable is 1.1m.The connection of pylon and tower is consolidation. The system of girder is supported.The span arrangement of the bridge is 102.5+240+102.5(meter), Because the structure is complex, and the location and role is special,so it's necessary to study seismic response and isolation of the bridge.First of all, The theoretical development of seismic profiles of long-span bridges is overviewed, and the analysis for seismic response spectrum and time history methods is presentated and discussed. the size of its earthquake response is preliminary understanded,to establish finite element model,as an engineering exampled, JiLin LanQi Songhuajiang River bridge—a single cable plane cable-stayed bridge. By dynamic analysis, to get its vibration characteristics.Second,by using response spectrum and the earthquake in the regular time-history analysis under El, to calculate the seismic response under longitudinal, transverse and vertical respectively, and the combined effect of the three largest earthquake in the direction of the total response.Then, the ductility concept and theoretical basis is introduced, the plastic design method is proposed, and the elastic-plastic dynamic model is established. The ductility seismic response under E2 earthquake is analysised,which is compared with the flexibility of the structure under rare earthquake. and the curvature ductility and displacement ductility of LanQi Songhuajiang River bridge tower are calculated. It is that LanQi Songhuajiang River bridge is not occurring brittle failure under E2 earthquake. But,as the end of beam's displacement is large,so it is necessary to set isotation to Songhuajiang River bridge.The last, to set isotation to Songhuajiang River bridge by using hydraulic damper, the displacement of the end of beam and the top of the tower is well cotrolled. And can significantly reduce bending moment of the bottom of the tower,which plays a very good role on absorption and protection of the effect of bridge structure. It is meeting the practical requirements of the project.