结构的弹塑性位移比及R-μ-T关系的分析
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摘要
在估计已知强度或延性的现有结构在不同地震动强度下的最大地震弹塑性反应时,弹塑性位移比谱和等延性强度谱是十分准确有效的.通过对342条地震记录进行单自由度体系的弹塑性时程分析,研究了三个特征周期设计分组在不同延性系数下的弹塑性位移比谱特性以及等延性强度谱的特性,通过非线性回归分析建立了等延性位移比谱和等延性强度谱,给出了回归计算公式.研究表明:(1)弹塑性位移比谱在周期为0~1.0 s时谱值随周期的增加急剧下降,下降区间的终点与地震分组有关,之后谱曲线转入平缓,且延性系数对平缓段的曲线影响较小;(2)延性系数μ>1时,等延性强度谱在周期区间为0~1.0 s时谱值随周期的增加急剧增长,上升区间的终点与地震分组有关,之后谱曲线增长较为平缓,等延性强度谱随延性系数增加而增加;(3)等延性位移比谱和等延性强度谱的回归计算公式能反映延性位移比和折减系数的统计规律,可应用于实际工程.
In the evaluation of existing structures with known lateral strength or ductility,the elastoplastic displacement ratios spectrum and equivalent constant strength spectrum are particularly accurate and useful to estimate maximum lateral elastoplastic displacement demands on existing structures.Based on the investigations of nonlinear time-history for single degree of freedom(SDOF) system of 324 earthquake ground motion records,the characteristics of the elastoplastic displacement ratios spectrum with various ductility coefficient and the characteristics of the constant-ductility strength spectrum in different design characteristic periods were detailedly studied.By means of nonlinear regression analysis,the simplified calculation formula of inelastic displacement ratios spectrum is fitted out under different ductility coefficient.Result shows that:(1) the plasticity displacement ratio spectrum decreases dramatically with the period when interval is in 0-1.0 seconds,the terminal of the decline period related to the design characteristic periods,after which the spectrum become gently and the effect of the ductility coefficient become less.(2) when μ>1,the constant-ductility strength spectrum increases with the period when interval is in 0-1.0 seconds,the top of the increase period related to the design characteristic periods,after which the spectrum become gently and the constant-ductility strength spectrum increases with ductility coefficient.(3) Regression formula of the constant-displacement ratios spectrum and the constant-ductility strength spectrum are able to reflect the statistical law of the ductility displacement ratio and reduction coefficient.They are capable to be applied in practical engineering.
In the evaluation of existing structures with known lateral strength or ductility,the elastoplastic displacement ratios spectrum and equivalent constant strength spectrum are particularly accurate and useful to estimate maximum lateral elastoplastic displacement demands on existing structures.Based on the investigations of nonlinear time-history for single degree of freedom(SDOF) system of 324 earthquake ground motion records,the characteristics of the elastoplastic displacement ratios spectrum with various ductility coefficient and the characteristics of the constant-ductility strength spectrum in different design characteristic periods were detailedly studied.By means of nonlinear regression analysis,the simplified calculation formula of inelastic displacement ratios spectrum is fitted out under different ductility coefficient.Result shows that:(1) the plasticity displacement ratio spectrum decreases dramatically with the period when interval is in 0-1.0 seconds,the terminal of the decline period related to the design characteristic periods,after which the spectrum become gently and the effect of the ductility coefficient become less.(2) when μ>1,the constant-ductility strength spectrum increases with the period when interval is in 0-1.0 seconds,the top of the increase period related to the design characteristic periods,after which the spectrum become gently and the constant-ductility strength spectrum increases with ductility coefficient.(3) Regression formula of the constant-displacement ratios spectrum and the constant-ductility strength spectrum are able to reflect the statistical law of the ductility displacement ratio and reduction coefficient.They are capable to be applied in practical engineering.
引文
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[7]卓卫东,范立础.结构抗震设计中的强度折减系数研究[J].地震工程与工程振动,2001,21(1):84-88.ZHUO Wei-dong,FAN Li-chu.Study on Strength Reduction Factors Used for Seismic Design of Structures[J].Earthquake Engineer-ing and Engineering Vibration,2001,24(1):84-88.
[8]翟长海,公茂盛,张茂花,等.工程结构等延性地震抗力谱研究[J].地震工程与工程振动,2004,24(1):22-29.ZHAI Chang-hai,GONG Mao-sheng,ZHANG Mao-hua,et al.On Seismic Resistance Spectra of Constant Ductility of Structures[J].Earthquake Engineering and Engineering Vibration,2004,24(1):22-29.
[9]吕西林,周定松.考虑场地类别与设计分组的延性需求谱和弹塑性位移反应谱[J].地震工程与工程振动,2004,24(1):39-48.LV Xi-lin,ZHOU Ding-song.Ductility Demand Spectra and Inelastic Displacement Spectra Considering Soil Conditions and DesignCharacteristic Periods[J].Earthquake Engineering and Engineering Vibration,2004,24(1):39-48.
[10]白绍良,李刚强,李英民,等.从R-μ-T关系研究成果看我国钢筋混凝土结构的抗震措施[J].地震工程与工程振动,2006,26(5):144-151.BAI Shao-liang,LI Gang-qiang,LI Ying-min,et al.Seismic Measures for RC Structures in View of R--μT Relation[J].EarthquakeEngineering and Engineering Vibration,2006,26(5):144-151.
[11]马英展,刘文锋,付兴潘.结构弹塑性折减系数法的研究[J].青岛理工大学学报,2008,29(2):27-31.MA Ying-zhan,LIU Wen-feng,FU Xing-pan.A Study of Reduction Factor Methods for Elastoplastic Analysis of Structures[J].Journal of Qingdao Technological University,2008,29(2):27-31.
[12]马英展,刘文锋,李怡.结构弹塑性等效线性化方法的研究[J].四川建筑科学研究,2008,34(3):153-157.MA Ying-zhan,LIU Wen-feng,LI Yi.Study of Equivalent Linearization Methods for Inelastic Analysis of Structures[J].SichuanBuilding Science,2008,34(3):153-157.
[13]徐福江,钱稼茹.常延性系数弹塑性位移谱及其应用[J].工程力学,2007,24(6):15-20.XU Fu-jiang,QIAN Jia-ru.Constant Ductility Inelastic Displacement Spectrum and Its Application[J].Engineering Mechanics,2007,24(6):15-20.
[2]Newmark N M,Hall W J.Earthquake Spectra and Design[M].Oakland:Earthquake Engineering Research Institute,1982.
[3]Krawinkler H,Nassar A A.Seismic Design Based on Ductility and Cumulative Damage Demands and Capacities[C]//Fajfar,Krawin-kler.Nonlinear Seismic Analysis and Design of Reinforced Concrete Buildings.New York:Elsevier Applied Science,1992:23-40.
[4]Miranda E,Bertero V V.Evaluation of Strength Reduction Factor for Earthquake-Resistance Design[J].Earthquake Spectra,1994,10(2):357-379.
[5]Vidic T,Fajfar P,Fischinger M.Consistent Inelastic Design Spectra:Strength and Displacement[J].Earthquake Engineering and Struc-tural Dynamics,1994,23(3):507-521.
[6]Borzi B,Elnashai A S.Refined Force Reduction Factors for Seismic Design[J].Journal of Engineering Structures,2000,22(5):1244-1260.
[7]卓卫东,范立础.结构抗震设计中的强度折减系数研究[J].地震工程与工程振动,2001,21(1):84-88.ZHUO Wei-dong,FAN Li-chu.Study on Strength Reduction Factors Used for Seismic Design of Structures[J].Earthquake Engineer-ing and Engineering Vibration,2001,24(1):84-88.
[8]翟长海,公茂盛,张茂花,等.工程结构等延性地震抗力谱研究[J].地震工程与工程振动,2004,24(1):22-29.ZHAI Chang-hai,GONG Mao-sheng,ZHANG Mao-hua,et al.On Seismic Resistance Spectra of Constant Ductility of Structures[J].Earthquake Engineering and Engineering Vibration,2004,24(1):22-29.
[9]吕西林,周定松.考虑场地类别与设计分组的延性需求谱和弹塑性位移反应谱[J].地震工程与工程振动,2004,24(1):39-48.LV Xi-lin,ZHOU Ding-song.Ductility Demand Spectra and Inelastic Displacement Spectra Considering Soil Conditions and DesignCharacteristic Periods[J].Earthquake Engineering and Engineering Vibration,2004,24(1):39-48.
[10]白绍良,李刚强,李英民,等.从R-μ-T关系研究成果看我国钢筋混凝土结构的抗震措施[J].地震工程与工程振动,2006,26(5):144-151.BAI Shao-liang,LI Gang-qiang,LI Ying-min,et al.Seismic Measures for RC Structures in View of R--μT Relation[J].EarthquakeEngineering and Engineering Vibration,2006,26(5):144-151.
[11]马英展,刘文锋,付兴潘.结构弹塑性折减系数法的研究[J].青岛理工大学学报,2008,29(2):27-31.MA Ying-zhan,LIU Wen-feng,FU Xing-pan.A Study of Reduction Factor Methods for Elastoplastic Analysis of Structures[J].Journal of Qingdao Technological University,2008,29(2):27-31.
[12]马英展,刘文锋,李怡.结构弹塑性等效线性化方法的研究[J].四川建筑科学研究,2008,34(3):153-157.MA Ying-zhan,LIU Wen-feng,LI Yi.Study of Equivalent Linearization Methods for Inelastic Analysis of Structures[J].SichuanBuilding Science,2008,34(3):153-157.
[13]徐福江,钱稼茹.常延性系数弹塑性位移谱及其应用[J].工程力学,2007,24(6):15-20.XU Fu-jiang,QIAN Jia-ru.Constant Ductility Inelastic Displacement Spectrum and Its Application[J].Engineering Mechanics,2007,24(6):15-20.
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