Issue 30

W. Changfeng et alii, Frattura ed Integrità Strutturale, 30 (2014) 486-494; DOI: 10.3221/IGF-ESIS.30.59 486 Effect of nonlinearity of restrainer and supports on the elasto-plastic seismic response of continuous girder bridge Wang Changfeng School of Civil Engineering, Yantai University, Yantai, China Wangchang-f@126.com Zhu Long, Chen Xingchong School of Civil Engineering, Lanzhou Jiaotong University, Lanzhou, China 932570069@qq.com , chenxingchong@263.net A BSTRACT . During an earthquake, the nonlinearity of the bridge structure mainly occurs at the supports, bridge piers and restrainers. When entering nonlinear stage, members of the bridge structure affect the elasto-plastic seismic response of the whole structure to a certain extent; for multi-span continuous bridges, longitudinal restrainers can be installed on the movable piers to optimise the distribution of seismic force and enable the movable piers to bear a certain amount of seismic effect. In order to evaluate the effect of nonlinearity of restrainer and supports on the elasto-plastic seismic response of continuous girder bridge, analytical models of continuous girder bridge structure considering the nonlinearity of movable supports, restrainers and bridge piers were built and the nonlinear time history analysis was conducted to evaluate the effect of nonlinearity of restraining devices and supports on the elasto-plastic seismic response of continuous girder bridge. Relevant structural measures and recommendation were made to reduce the seismic response of the fixed piers of the continuous girder bridge. K EYWORDS . Restraining devices; Supports; Elasto-plastic seismic response; Continuous girder bridge. I NTRODUCTION he investigations of previous seismic hazards showed that the damage of the bridge piers were not significant if failure occurred at the support, which suggests that the response of supports and bridge pier is interrelated; meanwhile, caging devices play a certain role in distributing the seismic force to each piers and abutments. Under earthquake action, the girder, supports, piers, substructure and connecting members (restraining blocks and girder- connection devices) act as an integrated structure. As a certain portion of energy will be dissipated by movable supports during earthquake and a part of the inertia force of the superstructure will be passed to movable piers, especially when the movable supports fail and lose the sliding capacity, in which case the seismic force passed from the failed support to the movable pier would be magnified [1], the seismic response of the whole bridge structure will change. When studying the elasto-plastic seismic response of bridge structures, the effect of the nonlinearity of each component in the bridge structure on elasto-plastic seismic response of bridge structures should be considered [2]. T