高速铁路大跨连续梁桥地震反应分析及抗震校核
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摘要
针对高速铁路大跨连续梁桥的结构特点,结合三水准的抗震设防目标,给出了各水准下桥梁的抗震验算指标。采用反应谱法及弹塑性时程反应分析法对一实桥进行了地震反应分析及抗震性能评价。结果表明固定墩控制该桥的抗震设计。在多遇地震作用下固定墩处于弹性状态;在罕遇地震作用下固定墩纵向进入塑性,但位移延性系数小于规范容许值,结构具有较高的延性储备。该桥的抗震能力满足三水准抗震设防目标。
Considering that earthquakes occur frequently in China,four vertical and four horizontal high-speed railway networks are planned,and 23 provincial capital cities and two-thirds of the cities with populations of more than a million are located in regions of high seismic intensity,seismic design is the controlling factor in the design of high-speed railway bridges.The differences between a high-speed railway bridge and a highway or common railway bridge lie in the following aspects: First,pier,bearing system,and displacement restrictions are required to strictly ensure that high-speed trains remain on the rails.Second,bridges make up a large proportion of the high-speed railway,and most of these bridges are viaducts and long.Third,the high-speed railway will have a major impact,being traffic intensive,high speed,high cost,and so on.Fourth,gravity piers(or hollow piers) are generally used in the substructures of such bridges,and these piers often have large section size and low reinforcement ratio.The long-span continuous bridge is the most widely used bridge type in Chinese high-speed railway construction,and the structural form of "multiple spans as one unit" is often used in this bridge type,with only one fixed pier per unit.Under earthquake force,the inertial force of the superstructure is mainly exerted on the fixed pier,so the fixed pier must meet the requirements of strength and ductility.For this reason,most fixed piers of long-span continuous bridges are reinforced concrete gravity piers.Under frequent earthquake action,piers are required to be elastic,and strength failure criterion can be used to check piers.Under rare earthquake action,because a pier would be in a plastic state,the deformation failure criteria would be used.The seismic checking index for each level is combined with the three-level seismic fortification goal based on the structural characteristics of a long-span continuous beam high-speed rail bridge.A seismic response analysis was performed on an actual bridge by use of a response spectrum method,and elasto-plastic history response analysis and seismic performance evaluation were also conducted.The results showed that the seismic design of the bridge was controlled by the fixed pier.The fixed pier is in an elastic state under low-level earthquake conditions.Under high-level earthquake conditions,however,it enters a plastic state in the longitudinal direction,but the displacement ductility factor is less than the allowable value so it has sufficient ductility capability in reserve.Therefore,the seismic capacity of the bridge meets the three-level seismic fortification goal.
Considering that earthquakes occur frequently in China,four vertical and four horizontal high-speed railway networks are planned,and 23 provincial capital cities and two-thirds of the cities with populations of more than a million are located in regions of high seismic intensity,seismic design is the controlling factor in the design of high-speed railway bridges.The differences between a high-speed railway bridge and a highway or common railway bridge lie in the following aspects: First,pier,bearing system,and displacement restrictions are required to strictly ensure that high-speed trains remain on the rails.Second,bridges make up a large proportion of the high-speed railway,and most of these bridges are viaducts and long.Third,the high-speed railway will have a major impact,being traffic intensive,high speed,high cost,and so on.Fourth,gravity piers(or hollow piers) are generally used in the substructures of such bridges,and these piers often have large section size and low reinforcement ratio.The long-span continuous bridge is the most widely used bridge type in Chinese high-speed railway construction,and the structural form of "multiple spans as one unit" is often used in this bridge type,with only one fixed pier per unit.Under earthquake force,the inertial force of the superstructure is mainly exerted on the fixed pier,so the fixed pier must meet the requirements of strength and ductility.For this reason,most fixed piers of long-span continuous bridges are reinforced concrete gravity piers.Under frequent earthquake action,piers are required to be elastic,and strength failure criterion can be used to check piers.Under rare earthquake action,because a pier would be in a plastic state,the deformation failure criteria would be used.The seismic checking index for each level is combined with the three-level seismic fortification goal based on the structural characteristics of a long-span continuous beam high-speed rail bridge.A seismic response analysis was performed on an actual bridge by use of a response spectrum method,and elasto-plastic history response analysis and seismic performance evaluation were also conducted.The results showed that the seismic design of the bridge was controlled by the fixed pier.The fixed pier is in an elastic state under low-level earthquake conditions.Under high-level earthquake conditions,however,it enters a plastic state in the longitudinal direction,but the displacement ductility factor is less than the allowable value so it has sufficient ductility capability in reserve.Therefore,the seismic capacity of the bridge meets the three-level seismic fortification goal.
引文
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[2]戴晓春,袁明,何庭国.高速铁路长联大跨连续梁桥地震响应分析[J].桥梁建设,2006,(2):144-146.DAI Xiao-chun,YUAN Ming,HE Ting-guo.Seismic Re-sponse Analysis of Long Span and Long Unit Continuous Gird-er Bridges on High Speed Railways[J].Bridge Construction,2006,(2):144-146.
[3]禚一,王菲.罕遇地震城际铁路连续梁桥延性抗震设计[J].铁道工程学报,2012,(4):66-72.ZHUO Yi,WANG Fei.Seismic Ductility Design for IntercityRailway Continuous Bridge Under Rare Earthquake[J].Jour-nal of Railway Engineering Society,2012,(4):66-72.
[4]邓小伟.基于两水平设防的连续梁桥抗震性能分析[J].石家庄铁道大学学报,2012,25(4):39-42.DENG Xiao-wei.Seismic Performance Analysis of ContinuousGirder Bridge Based on Two-level Design Approach[J].Jour-nal of Shijiazhuang Tiedao University,2012,25(4):39-42.
[5]苏虹,胡世德.连续梁桥的抗震性能分析[J].结构工程师,2002,(2):36-40.SU Hong,HU Shi-de.Seismic Analysis of the ContinuousBeam Bridge[J].Structural Engineers,2002,(2):36-40.
[6]张永亮,陈兴冲.轨道约束对简支梁桥弹塑性地震反应的影响[J].西北地震学报,2012,34(2):121-125.ZHANG Yong-liang,CHEN Xing-chong.Influnce of Rail Re-straints on Elasto-plastic Seismic Response of Simply Suppor-ted Girder Bridge[J].Northwestern Seismological Journal,2012,34(2):121-125.
[7]吴小峰,孙启国,狄杰建,等.抗震分析反应谱法和时程分析法数值仿真比较[J].西北地震学报,2011,33(3):275-278.WU Xiao-feng,Sun Qi-guo,Di Jie-jian,et al.A NumericalSimulation Comparison between Response Spectrum Analysisand Time History Analysis[J].Northwestern SeismologicalJournal,2011,33(3):275-278.
[8]R Park,et al.Bridge Manual of Transit New Zealand(secondedition 2003)[S].2005.
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