锈蚀钢筋混凝土柱等效塑性铰长度计算方法

Calculation method of equivalent plastic hinge length of corroded reinforced concrete columns

为了评估锈蚀钢筋混凝土(RC)柱变形能力及承载能力,提出了考虑弯曲效应及纵筋滑移效应的锈蚀RC柱等效塑性铰长度计算方法。首先,分析锈蚀RC柱的锈蚀损伤形态及破坏过程,定义了锈损混凝土本构关系,并考虑钢筋锈蚀对黏结强度与黏结应力分布的影响,建立了锈蚀钢筋混凝土黏结滑移模型;其次,结合截面P-M-φ分析得到了弯曲变形分量与纵筋滑移分量所对应塑性转角计算方法,采用曲率积分原理建立了锈蚀RC柱等效塑性铰长度计算公式;最后,将基于该公式所得等效塑性铰长度L_(p)计算值与柱顶荷载-位移计算曲线分别同试验结果进行对比。研究结果表明:L_(p)计算值与试验值相对误差较小,柱顶荷载-位移计算曲线与试验结果吻合较好,表明所建立锈蚀RC柱等效塑性铰长度计算方法准确度较高,可用于评估锈蚀RC柱承载力及变形性能。

In order to evaluate the deformation capacity and bearing capacity of corroded reinforced concrete(RC)columns,a calculation method for the equivalent plastic hinge length of corroded RC columns considering bending effect and sliding effect of longitudinal bars was proposed.Firstly,the corrosion pattern and failure phenomena of the corroded RC columns were analyzed to define the constitutive relationship of concrete.Considering the influence of steel corrosion on the bond strength and bond stress distribution,the corrosion bond-slip model was established.Secondly,the calculation method of plastic rotation angle corresponding to bending deformation component and longitudinal bars slip component was obtained by combining the P−M−φanalysis.The formula for calculating the equivalent plastic hinge length of corroded RC columns was obtained by adopting the principle of curvature integral.Finally,the calculated value of equivalent plastic hinge length and load−displacement calculation curve with the test results were compared.The results show that the relative error between the calculated L_(p) value and the test value is small.The load−displacement calculation curve agrees well with the test results,indicating the calculation method of equivalent plastic hinge length has high accuracy and can be used to evaluate the bearing capacity and deformation performance of corroded RC columns.