脉冲地震动缩放水平对结构非线性位移反应影响的分析
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摘要
研究缩放速度脉冲型地震动强度水平引起的单自由度(SDOF)体系非线性位移反应的偏差。采用30条速度脉冲地震记录,通过SDOF的体系动力时程分析,分析了速度脉冲型地震动分别缩放到不同目标谱加速度(Sa)、峰值加速度(PGA)、峰值速度(PGV)、峰值位移(PGD)水平时,SDOF体系非线性位移反应偏差随系统自振周期和强度折减系数变化的规律;通过对散点数据的对数线性回归确定了位移反应偏差的变化趋势,并比较了不同地面运动强度表征参数下位移偏差的稳定性。分析结果表明:位移偏差对地震动缩放系数、系统的基阶自振周期和系统的强度有一定的依赖性,合理选用缩放系数和地面运动强度表征参数能有效减小估算结构地震位移响应的偏差。
Nonlinear displacement biases in response of a single-degree-of-freedom(SDOF) systems were studied,they were induced by scaled pulse-like ground motion velocity records.Based on response time-history analysis of a SDOF system subjected to 30 pulse-like ground motions,the variation laws of the nonlinear displacement biases versus the structural vibration period(T) and the strength reduction factor(R) with scaling the earthquake records to the levels of target spectral acceleration(Sa),peak ground acceleration(PGA),peak ground velocity(PGV),and peak ground displacement(PGD) were studied.The variation trends of the displacement biases were determined with log-linear regression of scattered points,and the stability of the biases under the condition of scaling different ground motion intensities was comparatively analyzed.The results demonstrated that the amount of the displacement biases greatly depends on the scaling factor,the first modal period of the vibration,and the overall strength of the structure;reasonably selecting the scaling factor and the ground motion intensity presenting parameter of the pulse-like ground motion velocity records can reduce the displacement bias in structural seismic responses.
Nonlinear displacement biases in response of a single-degree-of-freedom(SDOF) systems were studied,they were induced by scaled pulse-like ground motion velocity records.Based on response time-history analysis of a SDOF system subjected to 30 pulse-like ground motions,the variation laws of the nonlinear displacement biases versus the structural vibration period(T) and the strength reduction factor(R) with scaling the earthquake records to the levels of target spectral acceleration(Sa),peak ground acceleration(PGA),peak ground velocity(PGV),and peak ground displacement(PGD) were studied.The variation trends of the displacement biases were determined with log-linear regression of scattered points,and the stability of the biases under the condition of scaling different ground motion intensities was comparatively analyzed.The results demonstrated that the amount of the displacement biases greatly depends on the scaling factor,the first modal period of the vibration,and the overall strength of the structure;reasonably selecting the scaling factor and the ground motion intensity presenting parameter of the pulse-like ground motion velocity records can reduce the displacement bias in structural seismic responses.
引文
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[3]Baker J W,Cornell C A.Vector-valued ground motionintensity measures for probabilistic seismic demand analysis[R].John A.Blume Earthquake Engineering Center,Stanford,CA,Report,2005,150,321.
[4]Luco N,Bazzurro P.Effects of earthquake record scaling onnonlinear structural response[R].PEER Lifelines Program,Report on PEER-LL Program Task 1G00,Addendum,2005,64.
[5]Luco N,Bazzurro P.Does amplitude scaling of ground motionrecords result in biased nonlinear structural drift responses-[J].Earthquake Engineering and Structural Dynamics,2007,36(13):1813-1835.
[6]Bazzurro P,Luco N.Do scaled and spectrum-matched near-source records produce biased nonlinear structural responses-[A].The 8thU.S.National Conf.on EarthquakeEngineering[C].San Francisco,2006.
[7]Baker J W.Measuring bias in structural response caused byground motion[A].The 8thPacific Conf.on EarthquakeEngineering[C].Vancouver,Paper,2007,056.
[8]Hancock J,Bommer J J,Stafford P J.Numbers of scaled andmatched accelerograms required for inelastic dynamic analyses[J].Earthquake Engineering and Structural Dynamics,2008,37(14):1585-1607.
[9]Krawinkler H,Medina R,Alavi B.Seismic drift and ductilitydemands and their dependence on ground motions[J].Engineering Structures,2003,25(5):637-653.
[10]Akkar S,Yazgan U,Gulkan P.Drift estimates in framebuilding subjected to near-fault ground motions[J].Journalof Structural Engineering,2005,121(7):1014-1024.
[11]Baker J W.Quantitative classification of near-fault groundmotions using wavelet analysis[J].Bulletin of theSeismological Society of America,2007,97(5):1486-1501.
[12]http://stanford.edu/～bakerjw/pulse-classification.html,2009.08.20.
[13]周靖,陈凯亮,罗高杰.速度脉冲型地震地面运动强度表征参数评估[J].振动与冲击,2010,29(7):153-158.
[2]Iervolino I,Cornell C A.Record selection for nonlinearseismic analysis of structures[J].Earthquake Spectra,2005,21(3):685-713.
[3]Baker J W,Cornell C A.Vector-valued ground motionintensity measures for probabilistic seismic demand analysis[R].John A.Blume Earthquake Engineering Center,Stanford,CA,Report,2005,150,321.
[4]Luco N,Bazzurro P.Effects of earthquake record scaling onnonlinear structural response[R].PEER Lifelines Program,Report on PEER-LL Program Task 1G00,Addendum,2005,64.
[5]Luco N,Bazzurro P.Does amplitude scaling of ground motionrecords result in biased nonlinear structural drift responses-[J].Earthquake Engineering and Structural Dynamics,2007,36(13):1813-1835.
[6]Bazzurro P,Luco N.Do scaled and spectrum-matched near-source records produce biased nonlinear structural responses-[A].The 8thU.S.National Conf.on EarthquakeEngineering[C].San Francisco,2006.
[7]Baker J W.Measuring bias in structural response caused byground motion[A].The 8thPacific Conf.on EarthquakeEngineering[C].Vancouver,Paper,2007,056.
[8]Hancock J,Bommer J J,Stafford P J.Numbers of scaled andmatched accelerograms required for inelastic dynamic analyses[J].Earthquake Engineering and Structural Dynamics,2008,37(14):1585-1607.
[9]Krawinkler H,Medina R,Alavi B.Seismic drift and ductilitydemands and their dependence on ground motions[J].Engineering Structures,2003,25(5):637-653.
[10]Akkar S,Yazgan U,Gulkan P.Drift estimates in framebuilding subjected to near-fault ground motions[J].Journalof Structural Engineering,2005,121(7):1014-1024.
[11]Baker J W.Quantitative classification of near-fault groundmotions using wavelet analysis[J].Bulletin of theSeismological Society of America,2007,97(5):1486-1501.
[12]http://stanford.edu/～bakerjw/pulse-classification.html,2009.08.20.
[13]周靖,陈凯亮,罗高杰.速度脉冲型地震地面运动强度表征参数评估[J].振动与冲击,2010,29(7):153-158.
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