多维地震下考虑桩-土相互作用的曲线桥地震响应分析
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摘要
为研究曲线桥梁在多维地震激励下考虑桩-土动力相互作用的地震响应特性,本文建立了空间桩-土脱离、摩阻和土体压缩非线性理论分析模型。为简化计算将该非线性弹簧模型进行线性化处理,结合有限元ANSYS分析平台建立了黄土场地的曲线桥仿真分析模型,对考虑桩-土相互作用的曲线桥进行了多维多工况数值分析,对比研究了曲线主梁跨中弯矩、墩底剪力和弯矩及桥墩顶位移的地震响应。结果表明:考虑桩-土相互作用的曲线桥梁主梁跨中内力与地震波输入方向密切相关,三维地震作用下主梁内力最大;各工况地震荷载作用下桥墩底部径向剪力响应比切向剪力响应大很多,而桥墩径向弯矩比切向弯矩略小;同一工况下不同桥墩顶切向位移响应大小相当,而径向位移差异较大。在进行非规则曲线桥梁抗震设计时,应充分考虑多维和单维地震激励输入工况。
To study the seismic response characteristics of curved bridges considering the pile-soil dynamic interaction under a multi-dimensional seismic excitation, a nonlinear theoretical analysis model of pile-soil interaction was established in this paper. To simplify the calculation process, the nonlinear spring model was linearized, and a simulation model of curved bridges on a loess site was established based on the finite element ANSYS analysis platform. A multi-dimensional and multi-condition numerical analysis of curved bridges, in the context of pile-soil interaction, was carried out. Analysis included the seismic response of the midspan bending moment of curved girder, the shear force and bending moment at the bottom of the pier, and the displacement at the top of the pier. The results showed that the midspan internal force of the main girder of the curved bridge, under given pile-soil interaction, was closely related to the direction of seismic wave input, and the internal force of the girder was the largest under three-dimensional seismic action. The radial shear force response at the bottom of the bridge pier was much larger than the tangential shear force response under the seismic load, while the radial bending moment of the bridge pier was slightly smaller than the tangential bending moment. Under the same loading condition, the top tangential displacement responses of different piers were the same, while the radial displacements were quite different. In the seismic design of irregular curved bridges, the input conditions of multi-dimensional and single-dimensional seismic excitation should be fully considered.
To study the seismic response characteristics of curved bridges considering the pile-soil dynamic interaction under a multi-dimensional seismic excitation, a nonlinear theoretical analysis model of pile-soil interaction was established in this paper. To simplify the calculation process, the nonlinear spring model was linearized, and a simulation model of curved bridges on a loess site was established based on the finite element ANSYS analysis platform. A multi-dimensional and multi-condition numerical analysis of curved bridges, in the context of pile-soil interaction, was carried out. Analysis included the seismic response of the midspan bending moment of curved girder, the shear force and bending moment at the bottom of the pier, and the displacement at the top of the pier. The results showed that the midspan internal force of the main girder of the curved bridge, under given pile-soil interaction, was closely related to the direction of seismic wave input, and the internal force of the girder was the largest under three-dimensional seismic action. The radial shear force response at the bottom of the bridge pier was much larger than the tangential shear force response under the seismic load, while the radial bending moment of the bridge pier was slightly smaller than the tangential bending moment. Under the same loading condition, the top tangential displacement responses of different piers were the same, while the radial displacements were quite different. In the seismic design of irregular curved bridges, the input conditions of multi-dimensional and single-dimensional seismic excitation should be fully considered.
引文
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[9] 赵琦.震陷时黄土地层中桩土相互作用特征研究[D].西安:西安建筑科技大学,2007.ZHAO Qi.Pile-soil Interaction Character Research under Subsidence in Loess Stratum[D].Xi’an:Xi’an University of Architecture and Technology,2007.
[10] 姜秀娟,赵国辉,刘健新.桩-土相互作用对弯桥的地震响应影响分析[J].中外公路,2007,27(6):108-110.JIANG Xiujuan,ZHAO Guohui,LIU Jianxin.Influence of Pile-soil Interaction on Seismic Response of Curved Bridge[J].Journal of China & Foreign Highway,2007,27(6):108-110.
[11] 单德山,李乔.铁路曲线梁桥抗震设计分析[J].重庆交通学院学报,2005(1):1-4,15.SHAN Deshan,LI Qiao.Seismic Design Analysis of Curved Beam Bridge on Railway[J].Journal of Chongqing Jiaotong University,2005(1):1-4,15.
[12] 曾敏.小半径曲线梁桥地震响应分析及减隔震研究[D].长沙:中南大学,2009.ZENG Min.Seismic Response Analysis and Seismic Mitigation of Curved Beam Bridge with Small Radius[D].Changsha:Central South University,2009.
[13] 全伟,李宏男.曲线桥多维地震时程分析主方向研究[J].振动与冲击,2008,27(8):20-25.QUAN Wei,LI Hongnan.Research on Critical Angle of Curved Bridge in Multi-Dimension Earthquake Time History Analysis[J].Journal of Vibration and Shock,2008,27(8):20-25.
[2] BHATTACHARYA S,ADHIKARI S,ALEXANDER N A.A Simplified Method for Unified Buckling and Free Vibration Analysis of Pile Supported Structures in Seismically Liquefiable Soils[J].Soil Dynamic and Earthquake Engineering,2009,29(8):1220-1235.
[3] 尚守平,卢华喜,王海东,等.大比例模型结构-桩-土动力相互作用试验研究与理论分析[J].工程力学,2006,23(增刊2):155-166.SHANG Shouping,LU Huaxi,WANG Haidong,et al.Test Investigation and Theoretical Analysis of Large-scale Model on Dynamic Soil-pile-structure Interaction[J].Engineering Mechanics,2006,23(Supp2):155-166.
[4] 楼梦麟,宗刚,牛伟星,等.土-桩-钢结构相互作用体系的振动台模型试验[J].地震工程与工程振动,2006,26(5):226-230.LOU Menglin,ZONG Gang,NIU Weixing,et al.Shaking Table Model Test of Soil-pile-steel Structure Interaction System[J].Earthquake Engineering and Engineering Vibration,2006,26(5):226-230.
[5] 康帅,楼梦麟,孔庆梅.土-结构相互作用问题中的放大效应研究[J].世界地震工程,2018,34(1):9-16.KANG Shuai,LOU Menglin,KONG Qingmei.Amplification Effect of Soil Structure Interaction Problem[J].World Earthquake Engineering,2018,34(1):9-16.
[6] 周爱红,袁颖,侯征,等.桩-土-结构体系随机地震响应的实用计算方法及参数分析[J].西北地震学报,2011,33(1):51-55.ZHOU Aihong,YUAN Ying,HOU Zheng,et al.Parametric Analysis and Practical Calculation Method for the Stochastic Seismic Response of Soil-Pile-Structure Interaction System[J].Northwestern Seismological Journal,2011,33(1):51-55.
[7] 凌贤长,王东升,王志强,等.液化场地桩-土-桥梁结构动力相互作用大型振动台模型试验研究[J].土木工程学报,2004,37(11):67-72.LING Xianchang,WANG Dongsheng,WANG Zhiqiang,et al.Large-scale Shaking Table Model Test of Interaction in Ground of Liquefaction[J].China Civil Engineering Journal,2004,37(11):67-72.
[8] BHATTACHARYA S,MADABHUSHI S P G,BOLTON M.Pile Instability During Earthquake Liquefaction[J].University of Cambridge,2003.
[9] 赵琦.震陷时黄土地层中桩土相互作用特征研究[D].西安:西安建筑科技大学,2007.ZHAO Qi.Pile-soil Interaction Character Research under Subsidence in Loess Stratum[D].Xi’an:Xi’an University of Architecture and Technology,2007.
[10] 姜秀娟,赵国辉,刘健新.桩-土相互作用对弯桥的地震响应影响分析[J].中外公路,2007,27(6):108-110.JIANG Xiujuan,ZHAO Guohui,LIU Jianxin.Influence of Pile-soil Interaction on Seismic Response of Curved Bridge[J].Journal of China & Foreign Highway,2007,27(6):108-110.
[11] 单德山,李乔.铁路曲线梁桥抗震设计分析[J].重庆交通学院学报,2005(1):1-4,15.SHAN Deshan,LI Qiao.Seismic Design Analysis of Curved Beam Bridge on Railway[J].Journal of Chongqing Jiaotong University,2005(1):1-4,15.
[12] 曾敏.小半径曲线梁桥地震响应分析及减隔震研究[D].长沙:中南大学,2009.ZENG Min.Seismic Response Analysis and Seismic Mitigation of Curved Beam Bridge with Small Radius[D].Changsha:Central South University,2009.
[13] 全伟,李宏男.曲线桥多维地震时程分析主方向研究[J].振动与冲击,2008,27(8):20-25.QUAN Wei,LI Hongnan.Research on Critical Angle of Curved Bridge in Multi-Dimension Earthquake Time History Analysis[J].Journal of Vibration and Shock,2008,27(8):20-25.