The Seismic Isolation Technology Of High-speed Railway Continuous Box Girder Bridge

Lead-rubber bearing(LRB) is an isolation device which can provide the vertical force, have the capacity of the restoring force and provide damping to burn off energy. It can prolong the natural period and increase the damping of structure to achieve the seismic isolation. It can meet the needs of large displacement in earthquake and has well stability after earthquake. It has powerful capability of dissipation energy and it’s damping ratio can be adjusted according to the design. Due to the covering of the rubber on the surface, it has the characteristics of better aging resistance. It’s superior performance can solve the problem of high-speed railway bridge’s construction in the earthquake.This paper conduct a study on application and research on that question of high-speed railway continuous beam bridge in earthquake zones which use LRB. The main work include three aspects as follows:1. By means of summarizing the mechanical properties and mechanical models of LRB and comparing the advantages and disadvantages, 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. Making improvements on the method of design which come from AASHTO, and taking two Beijing-Shanghai high-speed railway continuous box girder bridge ((48+80+48) m and (40+46+40) m) as an example, the parameters of LRB was designed. By the results of nonlinear time history analysis, rational isolation period was determined. Then, the paper provides some principles and recommendations of design of LRB.3. According to the design method come from this paper, this article discussed the problem of amplification effect of abutment pier in solation analysis of high-speed railway continuous beam bridge, and discussed the effect of isolation in different conditions which include different earthquake waves, different seismic intensity, different ratio of hardening and different plan of bearing arrangement.