Research On The Seismic Vulnerability Analysis Of Laminated Rubber Bearing

Compared with the far-field ground motion,the near-fault ground motion has more obvious velocity pulse of speed and has strong vertical ground motion,which causes more serious damage to the bridge structure.In order to reasonably evaluate the seismic damage of the laminated rubber bearings under the action of near-fault and farfield ground motions,this paper has analyzed the seismic vulnerability of the laminated rubber bearings of common highway simply supported bridges in China.Firstly,15 near-fault ground motions with obvious velocity pulses and 15 far-field vibrations were selected from the Taiwan Chi-Chi earthquake.Considering the uncertainty of the concrete strength of the pier and the strength of the steel bars,the Latin hypercube sampling method was used to establish 15 Seismic-structural analysis samples of nearfault ground motions and 15 groups of far-field vibrations.Secondly,based on the OpenSEEs seismic analysis software,the nonlinear seismic response analysis model of the structure is established according to the seismic-structural analysis samples,and the incremental dynamic analysis of the seismic-structural samples is carried out under the three working conditions of far-field vibration,near-fault long-period velocity pulse and near-fault long-period velocity pulse and vertical ground motion.Then,the bearing displacement ductility ratio and slip amount are taken as the structural damage index,and the traditional reliability probability analysis method is used to obtain the bearing vulnerability curve based on displacement ductility ratio and slip amount.Finally,the seismic vulnerability curves of bearings under different working conditions and different damage indexes are compared.The results show that the probability of bearing reaching a certain damage state under the action of near-fault long-period velocity pulse ground motion is significantly higher than that of far-field motion,and the vertical ground motion obviously increases the seismic response of bearing.The results of vulnerability curves based on bearing displacement ductility ratio and bearing slip are quite different,which should be paid attention to when they are used.