To study the seismic mitigation effects of the separated shock absorbers and sliding bearings applied to the high-speed railway bridges,the design principles and mechanical model for the absorbers and bearings were provided with reference to the characteristics of the bridges.Based on the design principles and mechanical model,a high-speed railway prestressed concrete (PC) simply-supported girder bridge of five spans of 32 m was taken as an example and the analysis of the mitigation effects of the absorbers and bearings was conducted.The finite element software ANSYS was used to set up the spatial model for the whole bridge of the simply-supported girder bridge and in consideration of the influences of the friction coefficients of the bearings,seismic intensity and train traveling speeds,the dynamic responses of the bridge with the absorbers and bearings were analyzed and were compared to those of the bridges with the normal bearings.The results of the analysis indicate that the applying of the separated shock absorbers and sliding bearings to the PC simply-supported girder bridge can achieve good seismic mitigation effects.The influences of the friction coefficients of the bearings on the pier footing bending moment and pier top displacement of the bridge with the absorbers and bearings are not great,but on the displacement of the girder are great.With the increase of the seismic intensity,the displacement of the absorbers and bearings accordingly increases and the seismic mitigation effects of the absorbers and bearings become still better.With the increase of the train traveling speeds,the transverse displacement of the girder of the bridge decreases and the mitigation effects on the pier footing bending moment are quite stable.%为研究分离式减震榫—活动支座应用于高速铁路桥梁的减震效果,结合该类桥梁的特点给出分离式减震榫—活动支座的设计原则以及力学模型,在此基础上以一座五跨32 m的高速铁路预应力混凝土简支梁桥为背景进行分析.采用有限元软件ANSYS建立全桥空间模型,考虑活动支座摩擦系数、地震强度以及车速的影响,分析应用分离式减震榫的桥梁的动力响应,并与普通支座桥梁进行对比.结果表明:将分离式减震榫应用于高速铁路简支梁桥具有较好的减震效果;活动支座摩擦系数对应用减震榫—活动支座的桥梁的墩底弯矩及墩顶位移的影响不大,对梁体位移影响较大;随着地震强度的增加,减震榫—活动支座的位移相应增加,减震榫减震效果越好;随着列车速度的增加,应用减震榫—活动支座的桥梁的梁体横向位移减小,减震榫对墩底弯矩的减震效果十分稳定.
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