近断层高烈度地震区铁路简支梁桥减隔震方案研究

Study on Seismic Reduction and Isolation Scheme of Railway Simply Supported Beam Bridge in Near Fault High Intensity Earthquake Area

近断层地震往往给工程结构造成较大的破坏,现行《铁路工程抗震设计规范》对近断层、减隔震问题尚未考虑。以某近断层高烈度地震区铁路简支梁桥为研究对象,梳理了国内外相关规范对近断层桥梁抗震的要求,提出相应的减隔震设计原则、设防标准。采用MIDAS软件建立桥梁有限元模型,运用非线性时程分析方法,考虑近场地震特性,进行了基于双曲面球形减隔震、黏滞阻尼器减震以及新型回形钢阻尼减隔震支座的减隔震效果研究。研究结果表明,传统的铁路桥梁减隔震措施难以满足近断层桥梁抗震要求,回形钢阻尼减隔震支座具有位移大、阻尼力可调、养护维修少、安装方便等特点,对近断层高烈度地震区简支梁的减隔震设计适应性好。

Near-fault earthquakes often cause great damage to engineering structures.The current Code for Seismic Design of Railway Engineering has not yet considered the issues of near-fault and seismic isolation.In this paper,a railway simply supported beam bridge in a near-fault high-intensity earthquake area is taken as the research object.The seismic requirements of near-fault bridges in relevant codes at home and abroad are reviewed,and corresponding seismic isolation design principles and fortification standards are put forward.The finite element model of the bridge is established with MIDAS software,and the nonlinear time-history analysis method is used to study the seismic isolation effect based on hyperbolic spherical seismic isolation,viscous damper absorbing and new type of steel damping isolation bearing.The research results show that the traditional seismic isolation measures of railway bridges can hardly meet the seismic requirements of near-fault bridges.The circular steel damping isolation bearing has the characteristics of large displacement,adjustable damping force,less maintenance and convenient installation.It has good adaptability to the seismic isolation design of simple-supported beams in near-fault high-intensity seismic areas.