（河北工业大学土木与交通学院， 天津 300401）

［摘要］为了研究轴压重复荷载作用下箍筋约束混凝土L形柱的性能，进行了5根箍筋约束混凝土L形短柱的轴心重复受压试验和1根箍筋约束混凝土L形短柱的单调轴心受压试验，研究了L形柱的破坏特征、滞回曲线、骨架曲线、应变发展和延性，并建立了延性系数计算公式。试验结果表明，轴压重复荷载作用下L形柱的破坏特征与单调荷载作用下相似，随着配箍特征值增大，破坏类型由斜向破坏转变为纵向压碎破坏，峰值荷载及相应位移增大，骨架曲线下降段越平缓，延性越好。延性系数计算结果与试验结果吻合良好。采用有限元软件ANSYS分析了轴压重复荷载作用下箍筋对L形柱核心混凝土的约束作用，约束机理与单调荷载作用下相似。建立了约束混凝土抗压强度、峰值应变与配箍特征值、箍筋有效约束系数的关系表达式，计算结果与试验结果吻合良好；并在此基础上建立了L形短柱轴压承载力计算公式，与试验结果比较，计算结果偏于安全，可用于轴压重复荷载作用下箍筋约束混凝土L形短柱的轴心受压承载力的分析。

［关键词］L形柱； 轴压重复荷载； 配箍特征值； 延性； 约束混凝土

中图分类号：TU375-3文献标识码：A文章编号：1002-848X(2019)06-0079-07

Research on the performance of L-shaped concrete columns confined by stirrups under axial repeated loads

Wang Xiaowei， Wei Shihua

（School of Civil Engineering and Transportation, Hebei University of Technology, Tianjin 300401, China）

Abstract:To study the performance of L-shaped concrete columns confined by stirrups under axial repeated loads, axial repeated loads tests of 5 L-shaped concrete short columns confined by stirrups and  axial monotonic load test of one specimen  were carried out. The failure characteristics, hysteresis curve, skeleton curve, strain development, ductility of L-shaped columns were studied and the formulas of ductility coefficient was established. The test results show that the failure characteristics of L-shaped columns under axial repeated loads are similar to those under axial loads. With the increase of stirrup characteristic value, the failure type changes from oblique failure to longitudinal crushing failure; the peak load and corresponding displacement of L-shaped columns increase; the descending segment of skeleton curves turns to be more flat and ductility becomes better. The calculated results of ductility coefficient are in good agreement with the experimental results. The restraint effect of stirrup on core concrete of L-shaped column was analyzed by using finite element software ANSYS, and the restraint mechanism is similar with axial load. The relation expressions between the compressive strength, peak strain and stirrup characteristic value, stirrup effective constraint coefficient were established; the calculated results are in good agreement with the experimental results. On this basis, the calculation formula of axial compression bearing capacity of L-shaped concrete short columns was established. The calculated results are relatively safe compared with the experimental results, and it can be used to analyze the axial compression bearing capacity of L-shaped concrete  short columns confined by stirrups under axial repeated loads.

Keywords:L-shaped column; axial repeated load; stirrup characteristic value; ductility; confined concrete