The Analysis Of The Wide Single-cable-plane Extradossed Cable-stayed Bridge’s Seismic Response And The Research Of Bridge Collision

The extradossed cable-stayed bridge is a kind of bridge structure which is newly developed in recent years, the structure includes firmness and flexibility,it has both characteristics of cable-stayed bridge and continuous beam bridge. For this bridge type (especially wide single-cable-plane extradossed cable-stayed bridge) the seismic research is still in its infancy. As earthquakes happen frequently all around, especially the year of2013Ya’an earthquake has brought us a painful lesson, so the analysis of extradossed cable-stayed bridge seismic response and the research of bridge collision is very necessary. In this paper, using SiFang bridge which located in the Suijiang County,Yunnan Province as engineering background to establish a full-bridge model with SAP2000to do the following research:(1)This paper introduces the simulation method of various components of the bridge in SAP2000, including the simulation of the main beam, cable, Sarasota, piers and boundary conditions.According to the analysis of the SiFang bridge model,we draw a conclusion of the dynamic characteristics of the main bridge and approach spans.And a simple analysis of the dynamic characteristics of SiFang main Bridge is done.(2)The analysis of SiFang main bridge and approach spans about earthquake spectrum response is done.The analysis of SiFang Main Bridge spectrum response under E1earthquake along the bridge, in transverse direction, in the vertical direction and in the three-way combination shows that every components of the SiFang main bridge is in elastic stage under E1earthquake. The analysis of approach spans spectrum response under E1and E2earthquake shows that the approach spans under E1earthquake, can achieve the goals of without damage or without repair",and can continue to be used, and has an adequate amount of surplus.Under E2earthquake, the bridge is safe and reliable,"will not collapse", it can also achieve the target.(3)The analysis of the SiFang main bridge under E2earthquake about time history response showe that under E2earthquake the pier column, pile foundation, cable, main tower of the SiFang main bridge can meet the seismic demand but the bridge standoffs does not meet the requirements, it is recommended to replace the proper types of seismic bridge standoffs.(4) Establish the full-bridge finite element model for bridge collision to analysis the factors that affect bridge collision based on nonlinear time history response, here comes the following conclusions:expansion joint gap, collision spring stiffness and the nonlinear stiffness of bridge standoffs are the factors affecting the bridge collision, and engineering measures are proposed to mitigate the collision of bridge including the establishment of a reasonable expansion joint gap and installation of energy-consuming devices.