High-speed Railway Bridge Mitigation And Isolation Studies

Lead-rubber bearing(LRB) has excellences such as simple structure, easily machining and installing, convenience and economy, which has excellent effect of seismic isolation on the high-speed railway bridge. It can provide hysteretic damping, vertical stiffness and horizontal flexibility, which can reduce the vibration frequency of beam, prolong the natural period and increase the damping of structure to achieve the seismic isolation. The superior performance of LRB is very important to vigorous development of high-speed railway construction in earthquake zones in China's future.This paper conducts a study on mechanical properties and seismic isolation theory of LRB with high-speed railway bridge, the main work is presented as follows:1. A series of analyses for mechanical properties and mechanical models of LRB were taken. Hysteretic model was simplified to ideal double linear model; the computing formulas were taken by American's AASHTO Code which can calculate the design parameters of LRB.2. Isolation period which is suitable to high-speed railway simplely-supported bridges was determined, method and the principle of design of LRB was proposed. Based on Beijing-Shanghai high-speed railway pre-stressed concrete simplely-supported bridge which locates in II site, corresponding section and mechanics parameters were calculated at the different spans, pier heights and earthquake intensity,which can provide reference for the design of LRB.3. According to the cross-section and mechanics parameters of LRB which were proposed, by time-history method, the dynamic responses of high-speed railway simple-supported bridge located inⅡsite were calculated at 5 different working condition,which proves the validity of arguments by the design method of LRB in this paper.