动水对斜拉桥结构动力响应影响研究
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摘要
深水大跨径斜拉桥在地震荷载作用下,桥梁水下部分与周围水体之间相互作用必然导致斜拉桥受到水体运动产生的动水力的作用。在已有Morison动水理论的基础上提出了一种适用于深水大跨径斜拉桥动力时程反应分析的动水力简便计算方法,并应用于南京长江第三大桥,分析了动水对斜拉桥结构的动力特性和地震反应的影响。研究发现:水与斜拉桥下部结构相互作用会使斜拉桥自振频率有所减小,其中第一阶自振频率相对无水时减小了8.24%;地震作用下动水对斜拉桥结构各个构件地震动力反应都有显著的影响,使主梁弯矩最多增大了7.73%,最不利桩位底部弯矩增大了14.22%。在深水斜拉桥结构进行抗震设计中,动水对斜拉桥动力响应的影响不容忽略。
When deep-water long span cable-stayed bridges are under seismic loads,the interaction between underwater structures and the surrounding water will inevitably lead to hydrodynamic forces on the bridges.Based on the Morison hydrodynamics theory,a simplified method for calculation of hydraulic force was proposed,adapting to time-history response analysis of cable-stayed bridges.Taken the Nanjing Yangtze River No.3 Bridge as a prototype,the hydrodynamic effects were analyzed.The main results include: 1) The natural vibration frequency of the cable-stayed bridge was decreased due to the interaction between water and substructure in deep water.2) The predominant frequency was reduced by 8.24% relative to no water condition.3) In earthquake,the effect of hydrodynamic force on the dynamic response of the elements in the cable-stayed bridge structure was significant,with the moment of the main beam being increased by 7.73% and the bottom moment of the most unfavorable pile being increased by 14.22%.4) In the seismic design of deep-water cable-stayed bridges,the effect of hydrodynamic force should not be ignored.
When deep-water long span cable-stayed bridges are under seismic loads,the interaction between underwater structures and the surrounding water will inevitably lead to hydrodynamic forces on the bridges.Based on the Morison hydrodynamics theory,a simplified method for calculation of hydraulic force was proposed,adapting to time-history response analysis of cable-stayed bridges.Taken the Nanjing Yangtze River No.3 Bridge as a prototype,the hydrodynamic effects were analyzed.The main results include: 1) The natural vibration frequency of the cable-stayed bridge was decreased due to the interaction between water and substructure in deep water.2) The predominant frequency was reduced by 8.24% relative to no water condition.3) In earthquake,the effect of hydrodynamic force on the dynamic response of the elements in the cable-stayed bridge structure was significant,with the moment of the main beam being increased by 7.73% and the bottom moment of the most unfavorable pile being increased by 14.22%.4) In the seismic design of deep-water cable-stayed bridges,the effect of hydrodynamic force should not be ignored.
引文
[1]JTG/T B02-01—2008公路桥梁抗震设计细则[S].北京:人民交通出版社,2008(JTG/T B02-01—2008Guidelines for seismic design of highway bridges[S].Beijing:China Communication Press,2008(in Chinese))
[2]Westergaard H M.Water pressure on dams during earth-quakes[C]//Transactions of the American Society of CivilEngineers,1998:418-433
[3]Hoshikuma J.Evaluation method of hydrodynamic pressureconsidering structural ductility seismic[C]//Proceedings ofthe 4th Bridge Seismic Design Considering StructuralDuctility Seismic.Tokyo,2000
[4]毕家驹,宁风.大直径多圆柱体近海结构上的二阶辐射水动力[J].水动力学研究与进展,1993,8(3):296-301(Bi Jiaju,Ning Feng.Second-order radiationforces on large multi-cylindrical offshore structures[J].Journal of Hydrodynamics,1993,8(3):296-301(inChinese))
[5]房营光,孙钧.平台-群桩-水流-土体系统的地震反应分析[J].土木工程学报,1998,31(5):56-64(FangYingguang,Sun Jun.Earthquake response analysis ofplatform pile group water-soil system[J].China CivilEngineering Journal,1998,31(5):56-64(in Chinese))
[6]赖伟,郑铁华,雷勇.Morison方程中动水阻力项对桥梁桩柱地震反应的影响[J].四川建筑科学研究,2007,33(4):163-168(Lai Wei,Zheng Tiehua,LeiYong.The effect of hydrodynamic drag force in Morisonequation on the seismic response of piles[J].SichuanBuilding Science,2007,33(4):163-168(in Chinese))
[7]Goto H,Toki K.Vibration characteristics and a seismicdesign of submerged bridge piers[C]//Proceedings of the3rd World Conference on Earthquake Engineer.NewZealand,1965
[8]日本道路协会.道路桥示方书[S].东京:丸善出版社,1995
[9]Uniform building code[S].Whittier,CA:InternationalConference of Building Officials,1997
[2]Westergaard H M.Water pressure on dams during earth-quakes[C]//Transactions of the American Society of CivilEngineers,1998:418-433
[3]Hoshikuma J.Evaluation method of hydrodynamic pressureconsidering structural ductility seismic[C]//Proceedings ofthe 4th Bridge Seismic Design Considering StructuralDuctility Seismic.Tokyo,2000
[4]毕家驹,宁风.大直径多圆柱体近海结构上的二阶辐射水动力[J].水动力学研究与进展,1993,8(3):296-301(Bi Jiaju,Ning Feng.Second-order radiationforces on large multi-cylindrical offshore structures[J].Journal of Hydrodynamics,1993,8(3):296-301(inChinese))
[5]房营光,孙钧.平台-群桩-水流-土体系统的地震反应分析[J].土木工程学报,1998,31(5):56-64(FangYingguang,Sun Jun.Earthquake response analysis ofplatform pile group water-soil system[J].China CivilEngineering Journal,1998,31(5):56-64(in Chinese))
[6]赖伟,郑铁华,雷勇.Morison方程中动水阻力项对桥梁桩柱地震反应的影响[J].四川建筑科学研究,2007,33(4):163-168(Lai Wei,Zheng Tiehua,LeiYong.The effect of hydrodynamic drag force in Morisonequation on the seismic response of piles[J].SichuanBuilding Science,2007,33(4):163-168(in Chinese))
[7]Goto H,Toki K.Vibration characteristics and a seismicdesign of submerged bridge piers[C]//Proceedings of the3rd World Conference on Earthquake Engineer.NewZealand,1965
[8]日本道路协会.道路桥示方书[S].东京:丸善出版社,1995
[9]Uniform building code[S].Whittier,CA:InternationalConference of Building Officials,1997
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