钢筋混凝土Z形截面双向受剪柱抗震性能试验研究

为研究钢筋混凝土Z形截面双向受剪柱的抗震性能，对4个缩尺比为1/2的试件进行拟静力试验，分析不同水平加载方向（加载角α分别取0°、45°、90°、135°）对其抗震性能的影响，研究Z形截面柱的破坏形态，得到试件的荷载-位移滞回曲线、骨架曲线、承载力、位移延性系数、刚度退化和耗能能力等力学性能指标。研究结果表明：试件在水平反复荷载作用下的破坏形态为弯剪破坏、弯曲破坏、剪切黏结破坏和剪切斜压破坏，其中剪切破坏的试件延性较差；双向水平荷载作用方向对Z形截面柱受剪承载力的影响近似符合椭圆规律，在加载角为45°时，试件的耗能能力最强，当加载角为0°和135°时，试件的耗能能力相差不大。提出钢筋混凝土Z形截面柱双向受剪承载力的计算方法，按该方法对本次试验和已有试验共22个试件进行计算，计算结果与试验值吻合较好。

Experimental study on seismic behavior of Z-shaped reinforced concrete columns subjected to biaxial shearing

In order to study the seismic performance of Z-shaped reinforced concrete columns subjected to biaxial shearing, quasi-static tests were carried out on four 1/2 scale specimens. The effects of the horizontal loading directions (α= 0°, 45°, 90°, 135°) were studied. And the failure characteristics, mechanical behaviors of Z-shaped columns were researched. The loading-displacement hysteretic loops and skeleton curves, load bearing capacity, displacement ductility, rigidity degradation and energy dissipation capacity were analyzed. Test results indicate four types of failure patterns can be seen from the test specimens, including shear-bending failure, bending failure, shear-bond failure, shear compression failure, and the shear failure ductility is very poor. It shows that the influences of the lateral bevel loads on the shear strength of Z-shaped RC frame columns can be approximately described by ellipse law. The capacity of energy dissipation is maximized in the case of 45°loading angle, and the variation is small when the loading angles are 0°and 135°. A calculation method of Z-shaped reinforced concrete columns subjected to biaxial shear bearing capacity was proposed. According to the proposed method, totally 22 sets of test data from the tests presented in this paper and other previous tests were used for the calculation. The calculation results are in good agreement with test values. 