大跨曲线桥多点激励下的地震响应分析
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摘要
用相位谱表征地震动频率的非平稳特性,用相干函数表征地震动空间变化的不相干效应,采用随频率变化的等效相速度代替随意给定的视波速表征地震动的行波效应,生成了具有强度和频率非平稳特性的多点地震动。将这种考虑时间和空间变化的地震动在水平方向作用于5跨高墩连续刚构曲线桥桥墩基础处,计算了墩顶位移及墩底内力,分析了大跨曲线桥多点输入中不相干效应和行波效应对结构响应的影响。结果表明考虑地震动空间变化特性的墩顶位移峰值多数显著大于一致激励。相干性显著增大了激励方向墩底的动内力,但对拟静力位移差动产生的内力有时增大有时减小,两者叠加后的总内力峰值多数大于一致激励。
When calculating the multi-point ground motions with non-stationary intensity and frequency,a phase spectrum is introduced to consider the non-stationary properties of the frequency contents,a coherence function is selected to consider the incoherence effect,and an equivalent phase velocity varying with the frequency of earthquake wave,rather than an arbitrary apparent velocity,is adopted to consider the traveling wave effect.The synthetic non-stationary ground motions can consider the temporal and spatial variation,which are used as inputting data for a curved continuous rigid-framed bridge with five spans and high piers in horizontal directions.The pier-top displacements and the pier-bottom internal forces of the bridge are calculated.The incoherence effect and the traveling wave effect are discussed.The results are concluded that when the spatial variation of the seismic ground motion is considered,the displacements of the majority piers are larger than that of uniform excitation,and also indicated that in the excitation direction the dynamic internal forces of the piers are increased apparently while the quasi-static forces caused by differential ground motions may be increased or decreased,and when the quasi-static response is superimposed with the dynamic one,the total internal forces of majority piers are larger than that of uniform excitation.
When calculating the multi-point ground motions with non-stationary intensity and frequency,a phase spectrum is introduced to consider the non-stationary properties of the frequency contents,a coherence function is selected to consider the incoherence effect,and an equivalent phase velocity varying with the frequency of earthquake wave,rather than an arbitrary apparent velocity,is adopted to consider the traveling wave effect.The synthetic non-stationary ground motions can consider the temporal and spatial variation,which are used as inputting data for a curved continuous rigid-framed bridge with five spans and high piers in horizontal directions.The pier-top displacements and the pier-bottom internal forces of the bridge are calculated.The incoherence effect and the traveling wave effect are discussed.The results are concluded that when the spatial variation of the seismic ground motion is considered,the displacements of the majority piers are larger than that of uniform excitation,and also indicated that in the excitation direction the dynamic internal forces of the piers are increased apparently while the quasi-static forces caused by differential ground motions may be increased or decreased,and when the quasi-static response is superimposed with the dynamic one,the total internal forces of majority piers are larger than that of uniform excitation.
引文
[1]袁万城,王玉贵,杨玉民,等.曲线梁桥空间地震反应分析[C]//第十二届全国桥梁学术会议论文集,广州,1996:585-590.Yuan Wancheng,Wang Yugui,Yang Yumin,et al.Seismic response analysis of curved girder bridges[C]//The 12th Proceeding of the NationalConference on Bridge Engineering,Guangzhou,1996:585-590.
[2]王丽.大跨度立交桥抗震设计理论与方法[D].北京:北京工业大学,2005.Wang Li.Seismic design theory and method of long span bridges[D].Beijing:Beijing University of Technology,2005.
[3]Harichandran R S.Estimation the spatial variation of earthquake ground motion from dense array recording[J].Structural Safety,1991,10:219-233.
[4]金星,廖振鹏.地震动相位特性的研究[J].地震工程与工程振动,1993,13(1):7-13.Jin Xing,Liao Zhenpeng.Study on phase properties of strong ground motions[J].Journal of Earthquake Engineering and Engineering Vibration,1993,13(1):7-13.
[5]Clough R W,Penzien J(著).结构动力学[M].王光远,等(译).北京:科学出版社,1983.Clough R W,Penzien J.Structural Dynamics[M].Wang Guangyuan(Translator).Beijing:Science Press,1983.
[6]Ohsaki Y.On the significance of phase content in earthquake ground motions[J].Earthquake Engineering&Structural Dynamics,1979,7(5):427-439.
[7]Thrainsson H,Kiremidjian A S.Simulation of digital earthquake accelerograms using the inverse discrete fourier transform[J].Earthquake Engi-neering and Structural Dynamics,2002,31:2023-2048.
[8]屈铁军,王前信.空间相关的多点地震动合成(Ⅰ)基本公式[J].地震工程与工程振动,1998,18(1):8-15.Qu Tiejun,Wang Qianxin.Simulation of spatial correlative time histories of multi-point grourd motion.Part 1:fundamental formulas[J].Journal ofEarthquake Engineering and Engineering Vibration,1998,18(1):8-15.
[2]王丽.大跨度立交桥抗震设计理论与方法[D].北京:北京工业大学,2005.Wang Li.Seismic design theory and method of long span bridges[D].Beijing:Beijing University of Technology,2005.
[3]Harichandran R S.Estimation the spatial variation of earthquake ground motion from dense array recording[J].Structural Safety,1991,10:219-233.
[4]金星,廖振鹏.地震动相位特性的研究[J].地震工程与工程振动,1993,13(1):7-13.Jin Xing,Liao Zhenpeng.Study on phase properties of strong ground motions[J].Journal of Earthquake Engineering and Engineering Vibration,1993,13(1):7-13.
[5]Clough R W,Penzien J(著).结构动力学[M].王光远,等(译).北京:科学出版社,1983.Clough R W,Penzien J.Structural Dynamics[M].Wang Guangyuan(Translator).Beijing:Science Press,1983.
[6]Ohsaki Y.On the significance of phase content in earthquake ground motions[J].Earthquake Engineering&Structural Dynamics,1979,7(5):427-439.
[7]Thrainsson H,Kiremidjian A S.Simulation of digital earthquake accelerograms using the inverse discrete fourier transform[J].Earthquake Engi-neering and Structural Dynamics,2002,31:2023-2048.
[8]屈铁军,王前信.空间相关的多点地震动合成(Ⅰ)基本公式[J].地震工程与工程振动,1998,18(1):8-15.Qu Tiejun,Wang Qianxin.Simulation of spatial correlative time histories of multi-point grourd motion.Part 1:fundamental formulas[J].Journal ofEarthquake Engineering and Engineering Vibration,1998,18(1):8-15.
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