考虑低周疲劳寿命的改进Park-Ang地震损伤模型
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摘要
随着基于性态抗震设计理论的发展 ,Park Ang双参数地震损伤模型在建立性态目标量化准则方面受到重视。本文的研究目的是结合钢筋混凝土构件低周疲劳试验结果 ,对该模型作进一步发展和完善。基于低周反复荷载作用下钢筋混凝土构件疲劳寿命方程 ,结合国内外发表的试验结果分析了构件极限滞回耗能与位移延性系数的关系 ,近似为指数衰减关系。通过引入另外的与加载路径有关的能量项加权因子 βi,由定义的临界延性系数 μ0 和能量等效系数YE 计算 ,提出了Park Ang双参数地震损伤模型新的改进形式。改进的地震损伤模型规格化最大位移与规格化滞回耗能是非线性组合 ,可以近似考虑加载路径对损伤影响。试验和数值分析表明改进损伤模型可以有效地降低组合参数 β不确定性对损伤指数计算结果的影响 ,而新引入参数的不确定性对其计算结果几乎没有影响。分析了滞回耗能在构件地震累积损伤中所占的比重及其与加载路径的关系。建议了改进Park Ang双参数地震损伤模型可修复破坏和倒塌破坏损伤指数临界值可分别取为 0 4和 0 8。
Particular attention is paid to the cumulative seismic damage model proposed by Park and Ang with the development of performance based seismic design recently,because it can be employed to numerically compute different structural damages during an earthquake and to define the performance design objectives.This study is aimed at improving this model with the consideration of low-cycle fatigue theory.The low-cycle fatigue life equation is introduced and correlation between the normalized deformation and the normalized limit of energy absorption for RC members under cyclic loading is investigated by means of regression analysis of the published test results.It is found there exists,approximately,an exponential decay relationship between them.By multiplying another energy weighted coefficient,which is related to the loading path and can be calculated by the critical ductility factor and the equivalent energy factor,the modified Park-Ang seismic damage model is obtained.Seismic structural damage is expressed as a nonlinear combination of the damage caused by excessive deformation and that contributed by cumulative fatigue damage.The effects of loading path on damage can be taken into account in this model.Test and numerical simulation results show that the damage computed by the modified Park-Ang damage model is not more sensitive to the non-negative parameter β than that by the Park-Ang damage model.Another two parameters introduced in the modified model also have little influence.The contribution of dissipated energy to cumulative damage and the relationship between the dissipated energy and the loading path are discussed.Seismic damage indices of D=0.4 and D=0.8 are suggested as the threshold values for repairable damage and collapse damage respectively.
Particular attention is paid to the cumulative seismic damage model proposed by Park and Ang with the development of performance based seismic design recently,because it can be employed to numerically compute different structural damages during an earthquake and to define the performance design objectives.This study is aimed at improving this model with the consideration of low-cycle fatigue theory.The low-cycle fatigue life equation is introduced and correlation between the normalized deformation and the normalized limit of energy absorption for RC members under cyclic loading is investigated by means of regression analysis of the published test results.It is found there exists,approximately,an exponential decay relationship between them.By multiplying another energy weighted coefficient,which is related to the loading path and can be calculated by the critical ductility factor and the equivalent energy factor,the modified Park-Ang seismic damage model is obtained.Seismic structural damage is expressed as a nonlinear combination of the damage caused by excessive deformation and that contributed by cumulative fatigue damage.The effects of loading path on damage can be taken into account in this model.Test and numerical simulation results show that the damage computed by the modified Park-Ang damage model is not more sensitive to the non-negative parameter β than that by the Park-Ang damage model.Another two parameters introduced in the modified model also have little influence.The contribution of dissipated energy to cumulative damage and the relationship between the dissipated energy and the loading path are discussed.Seismic damage indices of D=0.4 and D=0.8 are suggested as the threshold values for repairable damage and collapse damage respectively.
引文
[1] R .DBertero,V .V .Bertero.Performance basedSeismicEngineering:theNeedforReliableConceptualComprehensiveApproach[J].EarthquakeEng.StruDyn.2002,31:627～652
[2] DawnE .Lehman,JackP .Moehle.SeismicPerformanceofWellConfinedConcreteBridgeColumns[R ].UniversityofCalifornia,Berkeley,PEERReport:98-01
[3] Y .J .Park,H .S .Ang.MechanisticSeismicDamageModelforReinforcedConerete[J].JoumalofStructureEngi neering,ASCE .1985,111(4):722～739
[4] M .S .Williams,R .G .Sexsmith.SeismicDamageIndicesforConcreteStructures:AState ofArtRevietw[J].Earth quakeSpectra,1995,11(3):320～349
[5] 何政.钢筋混凝土结构非线性分析及地震损伤性能设计与控制[D].哈尔滨:哈尔滨工业大学,2000(10)
[6] 刘伯权,白绍良,徐云中,等.钢筋混凝土柱低周疲劳性能的试验研究[J].地震工程与工程振动,1998,18(4):82～89
[7] S .K .K .Kunnath.CumulativeSeismicDamageofRein forcedConcreteBridegePiers[R].UniversityatBuffalo,StateUniversityofNewYork,NCEERReport:97-0006
[8] Y .H .Chai,K .M .Romstad.CorrelationbetweeStain basedLowCircleFatigueandEnergy basedLinearDamageModels[J].EarthquakeSpectra,1997,13(2):191～208
[9] Y .J .Park,H .S .Ang.SeismicDamageAnalysisofRe inforcedConcreteBuildings[J].JournalofStructureEngi neering,ASCE ,1985,111(4):740～757
[10] 王东升.钢筋混凝土梁式桥地震破损研究[D].哈尔滨:中国地震局工程力学研究所,2002(9)
[2] DawnE .Lehman,JackP .Moehle.SeismicPerformanceofWellConfinedConcreteBridgeColumns[R ].UniversityofCalifornia,Berkeley,PEERReport:98-01
[3] Y .J .Park,H .S .Ang.MechanisticSeismicDamageModelforReinforcedConerete[J].JoumalofStructureEngi neering,ASCE .1985,111(4):722～739
[4] M .S .Williams,R .G .Sexsmith.SeismicDamageIndicesforConcreteStructures:AState ofArtRevietw[J].Earth quakeSpectra,1995,11(3):320～349
[5] 何政.钢筋混凝土结构非线性分析及地震损伤性能设计与控制[D].哈尔滨:哈尔滨工业大学,2000(10)
[6] 刘伯权,白绍良,徐云中,等.钢筋混凝土柱低周疲劳性能的试验研究[J].地震工程与工程振动,1998,18(4):82～89
[7] S .K .K .Kunnath.CumulativeSeismicDamageofRein forcedConcreteBridegePiers[R].UniversityatBuffalo,StateUniversityofNewYork,NCEERReport:97-0006
[8] Y .H .Chai,K .M .Romstad.CorrelationbetweeStain basedLowCircleFatigueandEnergy basedLinearDamageModels[J].EarthquakeSpectra,1997,13(2):191～208
[9] Y .J .Park,H .S .Ang.SeismicDamageAnalysisofRe inforcedConcreteBuildings[J].JournalofStructureEngi neering,ASCE ,1985,111(4):740～757
[10] 王东升.钢筋混凝土梁式桥地震破损研究[D].哈尔滨:中国地震局工程力学研究所,2002(9)
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