Effect of Rail Restraints on Seismic Responses of Cushioning Railway Bridges
Effect of Rail Restraints on Seismic Responses of Cushioning Railway Bridges
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发表时间：
2012
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通讯作者：
Chen Lie
中科院分区：
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作者：
Chen Lie
轨道结构是限制铁路桥梁垫层耗能性能的一个可能因素。为了分析钢轨约束对设置垫层的铁路桥抗震性能的影响，以两座设置不同垫层的高速客运专线32m跨度简支梁桥为研究对象，采用非线性弹簧单元模拟路基纵向位移-抗力关系。建立了轨道-桥梁模型。研究结果表明：轨道结构对设置垫层的铁路桥的自振频率的影响不容忽视，其影响程度随路基抗力的变化而变化，即路基抗力系数越大，轨道结构的自振频率越高；轨道约束对桥墩底部最大地震剪力的影响较小，对主梁纵向地震位移和垫层变形的影响有增有减，在铁路桥梁抗震设计中应考虑轨道约束引起的不利因素，适当提高相邻梁间允许位移的要求。
The track structure is a possible factor limiting the energy dissipation function of cushion seats of a railway bridge in earthquake.In order to analyze the effects of rail restraints on seismic behavior of railway bridges equipped with cushion seats,two 32 m-span simply-supported beam bridges of dedicated high-speed passenger railway lines installed with different cushion seats were taken as the objects for study.The longitudinal displacement-resistance relationship of roadbeds were simulated with nonlinear spring elements.The rail-bridge model was established,which was under the coaction of rail and bridge in earthquake.Elastic-plastic seismic responses were analyzed.The research results show as follows:The influence of the track structures on the natural frequencies of vibration of railway bridges with cushion seats cannot be ignored,and the degree of influence changes with the roadbed resistance,i.e.,the higher the roadbed resistance coefficient,the higher the natural frequency of vibration of the track structure;the influence of track restraints on the maximum seismic shear forces at the bottom of piers is small,the influence on longitudinal seismic displacements of girders and on deformations of cushion seats may be subject to both increase and decrease;unfavourable factors caused be track restraints should be taken into consideration in seismic design of railway bridges,requirements for allowable displacements between adjacent girders should be intensified adequately.