考虑基础提离与塑性的桥墩地震反应
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摘要
浅平基桥墩在承受强震作用时,其基础与地基之间会发生提离,地基土会进入塑性状态。精确模拟上述两个问题是非常困难的。本文分析中地基采用了能考虑基础提离及地基塑性的弹塑性Winkler地基模型,采用1940年El Centro(NS)地震记录作为输入,对三个不同高度的双柱式浅平基桥墩进行了非线性时程分析。研究结果表明,基础提离和地基塑性对双柱式桥墩的地震反应有很大影响。考虑地基非线性后,墩顶位移增大,剪力减小,对保护桥墩减小震害是有利的。
When the bridge piers with shallow foundation are subjected to intense earthquake excitations,the uplift of foundations will occur and the foundation soil will enter into plasticity.It is very difficult to use an accurate method to simulate the uplift and yield of supporting soil.An improved Winkler foundation model,which could be used to consider uplift and yield,was employed in the analysis.The 1940 El Centro(NS) earthquake record was input to a double-column bridge pier with shallow foundation,so that the nonlinear responses were obtained.The following conclusions can be drawn from the nonlinear analysis that the uplift and yield of supporting soil have important effect on the seismic responses of double-column bridge piers.Compared with the linear analysis,the displacement of the double-column piers increases and the internal force decreases.
When the bridge piers with shallow foundation are subjected to intense earthquake excitations,the uplift of foundations will occur and the foundation soil will enter into plasticity.It is very difficult to use an accurate method to simulate the uplift and yield of supporting soil.An improved Winkler foundation model,which could be used to consider uplift and yield,was employed in the analysis.The 1940 El Centro(NS) earthquake record was input to a double-column bridge pier with shallow foundation,so that the nonlinear responses were obtained.The following conclusions can be drawn from the nonlinear analysis that the uplift and yield of supporting soil have important effect on the seismic responses of double-column bridge piers.Compared with the linear analysis,the displacement of the double-column piers increases and the internal force decreases.
引文
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[7]李培振,吕西林.考虑土-结构相互作用的高层建筑抗震分析[J].地震工程与工程振动,2004,24(3):130-138.
[8]陈兴冲,朱②.弹塑性Winkler地基模型及其应用[J].工程力学,1997(增刊):355-359.
[9]陈兴冲,朱②.弹塑性Winkler地基上刚性浅平基桥墩水平力-位移关系的滞回特性分析[J].工程力学,1997(增刊):360-364.
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[11]陈兴冲,郑越.弹塑性Winkler地基上双柱式桥墩的地震反应[J].工程力学,2005,22(3):112-125.
[12]陈兴冲.重力式桥墩-地基的线性及非线性动力性态研究[D].北京:北方交通大学,1996.
[13]Siddharthan R,Ara A,Norris G M.Simple rigid plastic model for seismic tilting of rigid walls[J].Journal of Structural Engineering,ASCE,1989(118):469-487.
[14]朱伯龙,董振祥.钢筋混凝土非线性分析[M].上海:同济大学出版社,1985.
[15]朱②.桥墩抗震计算[M].北京:中国铁道出版社,1982.
[16]郑越.桥墩-地基系统的弹塑性地震反应分析[D].兰州:兰州交通大学,2003.
[2]Yim C-S,Chopra A K.Earthquake response of structures with partial uplift on Winkler foundation[J].Earthquake Engineering and StructuralDynamics,1984,12(2):263-281.
[3]Chopra AK,YimC-S.Simplified earthquake analysis of structures with foundation uplift[J].Journal of Structural Engineering,ASCE,1985,111(4):906-930.
[4]Wolf J P,Skrikerud P E.Seismic excitation with large overturning moments:Tensile capacity,projecting base mat or lifting-off?[J].NuclearEngineering and Design,1978,50(2):305-321.
[5]Izumi M,Sakamoto I,Chiba O,et al.Rocking vibration considering uplift and yielding of supporting soil[C]//Proc.4th Japanese EarthquakeEngineering Symposium,Tokyo,1975:727-734.
[6]王荣昌,俞载道,应稼年.地基土与多层剪切型结构的非线性动力分析[J].同济大学学报,1988,16(1):45-53.
[7]李培振,吕西林.考虑土-结构相互作用的高层建筑抗震分析[J].地震工程与工程振动,2004,24(3):130-138.
[8]陈兴冲,朱②.弹塑性Winkler地基模型及其应用[J].工程力学,1997(增刊):355-359.
[9]陈兴冲,朱②.弹塑性Winkler地基上刚性浅平基桥墩水平力-位移关系的滞回特性分析[J].工程力学,1997(增刊):360-364.
[10]陈兴冲,朱②.允许提离的弹塑性Winkler地基上桥墩的地震反应[J].工程力学,1999,16(5):101-107.
[11]陈兴冲,郑越.弹塑性Winkler地基上双柱式桥墩的地震反应[J].工程力学,2005,22(3):112-125.
[12]陈兴冲.重力式桥墩-地基的线性及非线性动力性态研究[D].北京:北方交通大学,1996.
[13]Siddharthan R,Ara A,Norris G M.Simple rigid plastic model for seismic tilting of rigid walls[J].Journal of Structural Engineering,ASCE,1989(118):469-487.
[14]朱伯龙,董振祥.钢筋混凝土非线性分析[M].上海:同济大学出版社,1985.
[15]朱②.桥墩抗震计算[M].北京:中国铁道出版社,1982.
[16]郑越.桥墩-地基系统的弹塑性地震反应分析[D].兰州:兰州交通大学,2003.
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