基于改进Ibarra-Medina-Krawinkler材料模型的RC圆柱恢复力模型参数识别

IDENTIFICATION OF THE HYSTERETIC MODEL PARAMETERS FOR REINFORCED CONCRETE CIRCULAR COLUMNS BASED ON THE MODIFIED IBARRA-MEDINA-KRAWINKLER MATERIAL MODEL

该文基于美国太平洋地震工程研究中心结构性能数据库中的76根弯曲破坏及弯剪破坏的钢筋混凝土(Reinforced concrete,RC)圆柱试验数据,以峰值指向型改进Ibarra-Medina-Krawinkler(I-M-K)材料模型作为恢复力模型,采用OpenSEES有限元平台对所选择的RC圆柱试验数据进行数值模拟,识别得到了每一RC圆柱的恢复力模型参数。选取RC圆柱的15个基本设计参数为基本变量,采用多元线性回归和分步拟合,获得了RC圆柱恢复力模型参数的经验预测公式(值)。通过对试验验证组中3根RC圆柱的滞回试验数据进行模拟,对该文提出的RC圆柱恢复力模型参数的经验预测公式(值)的合理性进行了验证。结果表明:该文获得的经验预测公式(值)可以较为准确地预测RC圆柱的恢复力模型参数,可以较合理地反映RC圆柱在循环加载过程中的强度及刚度的退化特征。

The hysteretic model parameters of reinforced concrete circular columns are identified in this paper.The test data of 76 flexural or flexural-shear failure RC circular columns from the Structural Performance Database by the Pacific Earthquake Engineering Research Center was collected as the database.A peak-oriented type of material modelled by the modified Ibarra-Medina-Krawinkler(I-M-K)material model was used as the basic hysteretic model of RC circular columns.The OpenSEES finite element platform was adopted to simulate each of the considered test data,and the corresponding hysteretic model parameters were identified.A total of 15 design parameters of RC circular columns were considered as the basic variables.Through multiple linear regression and stepwise regression analyses,the empirical relationships were developed to predict the hysteretic model parameters,which were validated by simulating three RC circular column specimens that were not included in the test database.The results show that the presented empirical equations(or values)can reasonably predict the hysteretic model parameters.The presented empirical equations(or values)also well reflected the characteristics of the strength and stiffness degradation of RC circular columns under cyclic loadings.