Abstract：Abstract：Research purposes： High speed railway large span simple supported girder bridges in high seismic intensity area have remarkable characteristics with big mass, large span and difficult seismic design. Aniti-seismic needs could be satisfied by strengthening pier and pile concrete reinforcement under frequent occurred earthquake, but it is still a problem under rarely occurred earthquake to ensure the safety of the structure. The paper carries out research on 48 m simple supported box girder bridge in high seismic intensity area with 0.3g of Baoji-Lanzhou passenger dedicated line, and takes shock absorber as seismic isolation on the pier. Research conclusions： (1) Adopting idea of "bearing function separation", shock absorber is a simple and advanced device which separates the bearing transmitting horizontal forces from vertical supporting completely, vertical forces and rotation are still realized by bearing, and horizontal forces and displacement are realized by shock absorber. (2) The damping efficiency of shock absorber varies with different pier height along bridge direction, when pier height≤12 m, the damping efficiency could be as high as 54% under frequent occurred earthquake, when pier height is 20 m, the damping efficiency is 29%, and the transverse damping efficiency is 43%~55%. (3) The earthquake forces applying shock absorber under rarely occurred earthquake could be reduced to a level which is equal to frequent occurred earthquake level; with the increase of pier height, rarely occurred earthquake forces that using shock absorb will be a little bigger than frequent earthquake forces without shock absorber. (4) The research result can provide references on large span bridge seismic isolation design and construction in high seismic intensity area in the future.
2017, Vol. 34 
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