大跨度多塔斜拉桥随机地震响应分析
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摘要
以嘉绍跨江大桥为工程背景,采用ANSYS有限元软件建模对随机地震动作用下大跨度多塔斜拉桥的结构动力响应进行了数值分析。结果显示,三维一致激励下各跨主梁位移响应规律基本一致,但各塔塔底内力差别较大;各塔塔底内力受该塔塔梁约束条件影响较大;同时各塔间塔梁约束方式对塔底内力存在相互影响。此外分析了行波效应对动力响应的影响,表明不同波速对结构地震响应影响较大,且随视波速变化结构响应存在一定的规律性。
This paper establishes a structural model of the Jiashao river-spanning bridge using the ANSYS finite element software,in which the tower and the beam are simulated by beam44.In addition,link8 is used to simulate the cables in the model.Through the solving of the dynamic equation,the results of the model show the dynamic response of the Jiashao bridge.This paper analyzes these responses to study the principles of structural dynamic response of a large-span multitower cable-stayed bridge under a stochastic seismic effect.The results show that,on the whole,the displacement of a beam at each span under three-dimensional uniform excitation has the same response.The horizontal and vertical RMSresponse of a beam's displacement gradually increases from the base of a tower toward the center of the beam,but the value in each span varies to certain extent.The longitudinal bending moment of the tower,where the height is lower than the place of constraint of the tower-girder,increases linearly with reduction in the height of the tower,but the bending moment of the remainder of the tower decreases with increase in the height of the tower.With respect to the different longitudinal constraints of the tower-girder in the models,the displacement of the main beam in the middle span and the internal forces in the base of the towers show clear differences among the models.Analysis shows that the internal forces in the base of the towers are deeply affected by the constraint conditions of the tower-girder,and that there is interaction between the constraint conditions of the tower-girder and the internal forces in the base of the towers.When each tower is under a longitudinal constraint,the RMSof the vertical displacement of a beam reaches its maximum value.The displacement is intermediate when each tower has vertical dampers(parts of towers have vertical constraints)and the minimum values of displacement are obtained when each tower has only vertical dampers.If a longitudinal tower-girder constraint is set in a tower,the internal forces in the bases of the towers are significantly enhanced as compared to when dampers are used.In addition,in this study,the traveling wave effect on the dynamic response of a large-span multi-tower cable-stayed bridge was analyzed.The results show that the RMSvalue curves of the longitudinal displacement of a beam are similar under different seismic wave velocities.The minimum value is obtained at the location where the longitudinal tower-girder constraint is set,and the displacement gradually increases toward the center span.When the seismic wave velocity is in a lower range of values,the relationship between the velocity and the longitudinal displacement of the main beam is not very obvious,but when the velocity is in a larger range of values,the longitudinal displacement of the main beam increases with increase in velocity.Furthermore,the RMS values of the base of a tower's moment and shear show the same variation as the displacement of a beam under different velocities.In general,this study indicates that the traveling wave effect has the greatest impact on the response,and that there is a certain relationship between structural response and a traveling wave.
This paper establishes a structural model of the Jiashao river-spanning bridge using the ANSYS finite element software,in which the tower and the beam are simulated by beam44.In addition,link8 is used to simulate the cables in the model.Through the solving of the dynamic equation,the results of the model show the dynamic response of the Jiashao bridge.This paper analyzes these responses to study the principles of structural dynamic response of a large-span multitower cable-stayed bridge under a stochastic seismic effect.The results show that,on the whole,the displacement of a beam at each span under three-dimensional uniform excitation has the same response.The horizontal and vertical RMSresponse of a beam's displacement gradually increases from the base of a tower toward the center of the beam,but the value in each span varies to certain extent.The longitudinal bending moment of the tower,where the height is lower than the place of constraint of the tower-girder,increases linearly with reduction in the height of the tower,but the bending moment of the remainder of the tower decreases with increase in the height of the tower.With respect to the different longitudinal constraints of the tower-girder in the models,the displacement of the main beam in the middle span and the internal forces in the base of the towers show clear differences among the models.Analysis shows that the internal forces in the base of the towers are deeply affected by the constraint conditions of the tower-girder,and that there is interaction between the constraint conditions of the tower-girder and the internal forces in the base of the towers.When each tower is under a longitudinal constraint,the RMSof the vertical displacement of a beam reaches its maximum value.The displacement is intermediate when each tower has vertical dampers(parts of towers have vertical constraints)and the minimum values of displacement are obtained when each tower has only vertical dampers.If a longitudinal tower-girder constraint is set in a tower,the internal forces in the bases of the towers are significantly enhanced as compared to when dampers are used.In addition,in this study,the traveling wave effect on the dynamic response of a large-span multi-tower cable-stayed bridge was analyzed.The results show that the RMSvalue curves of the longitudinal displacement of a beam are similar under different seismic wave velocities.The minimum value is obtained at the location where the longitudinal tower-girder constraint is set,and the displacement gradually increases toward the center span.When the seismic wave velocity is in a lower range of values,the relationship between the velocity and the longitudinal displacement of the main beam is not very obvious,but when the velocity is in a larger range of values,the longitudinal displacement of the main beam increases with increase in velocity.Furthermore,the RMS values of the base of a tower's moment and shear show the same variation as the displacement of a beam under different velocities.In general,this study indicates that the traveling wave effect has the greatest impact on the response,and that there is a certain relationship between structural response and a traveling wave.
引文
[1]胡聿贤.地震工程学[M].北京:地震出版社,2006.HU Yu-xian.Earthquake Engineering[M].Beijing:Seismological Press,2006.(in Chinese)
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[3]徐利平.超大跨径斜拉桥的结构体系分析[J].同济大学学报:自然科学版,2003,31(4):400-403.XU Li-ping.Structural System Analysis for Super-long Span Cable-stayed Bridges[J].Journal of Tongji University:Natural Science,2003,31(4):400-403.(in Chinese)
[4]王鼎,李杰.工程场地地震动随机场的物理模型[J].中国科学:技术科学,2012,42(7):798-807.WANG Ding,LI Jie.A Random Physical Model of Seismic Ground Motion Field on Local Engineering Site[J].Sci China:Tech Sci,2012,42(7):798-807.(in Chinese)
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[6]贾宏宇,郑史雄.直接求解多维多点地震动方程的虚拟激励法[J].工程力学,2013,30(3):341-346.JIA Hong-yu,ZHENG Shi-xiong.Pseudo Excitation Method of Direct Solving Ground Motion Equation of Multi-dimensional and Multi-support Excitation[J].Engineering Mechanics,2013,30(3):341-346.(in Chinese)
[7]中交公路规划设计院有限公司.嘉兴至绍兴跨江公路通道嘉绍大桥施工图设计[R].2010.CCCC Highway Consultants CO Ltd.Construction Drawing Design of Highway Across the River from Jiaoxing to Shaoxing-Jiaoshao Bridge[R].2010.(in Chinese)
[8]中华人民共和国交通运输部.公路桥梁抗震设计细则(JTG/T D65-01-2007)[S].北京:人民交通出版社,2008.Ministry of Transport of the People’s Republic of China.Guidelines for Seismic Design of Highway Bridges(JTG/T D65-01-2007)[S].Beijing:China Communication Press,2008.(in Chinese)
[9]李英民,刘立平,赖明.工程地震动随机功率谱模型的分析和改进[J].工程力学,2008,25(3):43-48.LI Ying-ming,LIU Li-ping,LAI Ming.Analysis and Improvement of Power Random Spectra of Strong Ground Motions for Engineering Purpose[J].Engineering Mechanics,2008,25(3):43-48.(in Chinese)
[10]李立峰,刘本永,张晨熙,等.中等跨径斜拉桥塔梁弹性约束装置的减震效应研究[J].地震工程与工程振动,2012,33(1):146-152.LI Li-feng,LIU Ben-yong,ZHANG Chen-xi,et al.Research on the Seismic Performance of Mid-span Cable-stayed Bridges with Elastic Constrains Between Tower and Beam[J].Journal of Earthquake Engineering and Engineering Vibration,2013,33(1):146-152.(in Chinese)
[11]武芳文,薛成凤,赵雷.超大跨度斜拉桥考虑行波效应的地震动随机响应研究[J].地震学报,2010,32(2):193-202.WU Fang-wen,Xue Cheng-feng,ZHAO Lei.Stochastic Seismic Response of Super-long Span Cable-stayed Bridge Under Excitation of Traveling Waves[J].Acta Seismologica Sinica,2002,32(2):193-202.(in Chinese)
[12]喻明秋,祝兵,张斗龙.基于Newmark-β显式直接积分法的三塔斜拉桥非线性地震响应分析[J].西北地震学报,2012,34(3):245-263.YU Ming-qiu,ZHU Bing,ZHANG Dou-long.Nonlinear Earthquake Response Analysis on Three-tower Cable-stayed Bridge Based on Newmark-βExplicit Scheme Direct Integration Method[J].Northwestern Seismological Journal,2013,35(2):226-231.(in Chinese)
[13]张永亮,孙建飞,徐家林.高速铁路大跨连续梁桥地震反应分析及抗震校核[J].地震工程学报,2012,34(3):245-263.ZHANG Yong-liang,SUN Jian-fei,XU Jia-lin.Analysis of Seismic Response and Seismic Checking in a Long-span Continuous Beam Bridge on a High-speed Railway[J].China Earthquake Engeering Journal,2012,34(3):245-263.(in Chinese)
[2]俞琦,陈语,王家林.桥梁抗震分析方法[J].重庆交通学院学报,2006(25):32-34.YU Qi,CHEN Yu,WANG Jia-lin.Seismic Analysis Methods of Bridges[J].Journal of Chongqing Jiaotong University,2006(25):32-34.(in Chinese)
[3]徐利平.超大跨径斜拉桥的结构体系分析[J].同济大学学报:自然科学版,2003,31(4):400-403.XU Li-ping.Structural System Analysis for Super-long Span Cable-stayed Bridges[J].Journal of Tongji University:Natural Science,2003,31(4):400-403.(in Chinese)
[4]王鼎,李杰.工程场地地震动随机场的物理模型[J].中国科学:技术科学,2012,42(7):798-807.WANG Ding,LI Jie.A Random Physical Model of Seismic Ground Motion Field on Local Engineering Site[J].Sci China:Tech Sci,2012,42(7):798-807.(in Chinese)
[5]曹资,薛素铎.空间结构抗震理论与设计[M].北京:科学出版社,2006.CAO Zi,XUE Su-duo.Seismic Analysis and Design of Spatial Structures[M].Beijing:Science Press,2006.(in Chinese)
[6]贾宏宇,郑史雄.直接求解多维多点地震动方程的虚拟激励法[J].工程力学,2013,30(3):341-346.JIA Hong-yu,ZHENG Shi-xiong.Pseudo Excitation Method of Direct Solving Ground Motion Equation of Multi-dimensional and Multi-support Excitation[J].Engineering Mechanics,2013,30(3):341-346.(in Chinese)
[7]中交公路规划设计院有限公司.嘉兴至绍兴跨江公路通道嘉绍大桥施工图设计[R].2010.CCCC Highway Consultants CO Ltd.Construction Drawing Design of Highway Across the River from Jiaoxing to Shaoxing-Jiaoshao Bridge[R].2010.(in Chinese)
[8]中华人民共和国交通运输部.公路桥梁抗震设计细则(JTG/T D65-01-2007)[S].北京:人民交通出版社,2008.Ministry of Transport of the People’s Republic of China.Guidelines for Seismic Design of Highway Bridges(JTG/T D65-01-2007)[S].Beijing:China Communication Press,2008.(in Chinese)
[9]李英民,刘立平,赖明.工程地震动随机功率谱模型的分析和改进[J].工程力学,2008,25(3):43-48.LI Ying-ming,LIU Li-ping,LAI Ming.Analysis and Improvement of Power Random Spectra of Strong Ground Motions for Engineering Purpose[J].Engineering Mechanics,2008,25(3):43-48.(in Chinese)
[10]李立峰,刘本永,张晨熙,等.中等跨径斜拉桥塔梁弹性约束装置的减震效应研究[J].地震工程与工程振动,2012,33(1):146-152.LI Li-feng,LIU Ben-yong,ZHANG Chen-xi,et al.Research on the Seismic Performance of Mid-span Cable-stayed Bridges with Elastic Constrains Between Tower and Beam[J].Journal of Earthquake Engineering and Engineering Vibration,2013,33(1):146-152.(in Chinese)
[11]武芳文,薛成凤,赵雷.超大跨度斜拉桥考虑行波效应的地震动随机响应研究[J].地震学报,2010,32(2):193-202.WU Fang-wen,Xue Cheng-feng,ZHAO Lei.Stochastic Seismic Response of Super-long Span Cable-stayed Bridge Under Excitation of Traveling Waves[J].Acta Seismologica Sinica,2002,32(2):193-202.(in Chinese)
[12]喻明秋,祝兵,张斗龙.基于Newmark-β显式直接积分法的三塔斜拉桥非线性地震响应分析[J].西北地震学报,2012,34(3):245-263.YU Ming-qiu,ZHU Bing,ZHANG Dou-long.Nonlinear Earthquake Response Analysis on Three-tower Cable-stayed Bridge Based on Newmark-βExplicit Scheme Direct Integration Method[J].Northwestern Seismological Journal,2013,35(2):226-231.(in Chinese)
[13]张永亮,孙建飞,徐家林.高速铁路大跨连续梁桥地震反应分析及抗震校核[J].地震工程学报,2012,34(3):245-263.ZHANG Yong-liang,SUN Jian-fei,XU Jia-lin.Analysis of Seismic Response and Seismic Checking in a Long-span Continuous Beam Bridge on a High-speed Railway[J].China Earthquake Engeering Journal,2012,34(3):245-263.(in Chinese)
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