约束混凝土方形截面柱轴压承载力计算方法

The GB 50010-2010 'Code for design of concrete structures' specifies that when considering the constraint effect of stirrup, the spacing of stirrup should not be greater than 80 mm and 1/5 of the core diameter. The ACI 318-14 'Building code requirements for structural concrete and commentary' specifies that the clear spacing should not be greater than 75 mm and less than 25 mm when considering the constraint effect of stirrup. The above-mentioned provisions will cause construction difficulties due to closely spaced stirrups. On the other hand, there is a lack of reasonable consideration for constraint effect when stirrup spacing is relatively large. Based on the collected test results of full-scale confined concrete columns, the axial bearing capacity of confined concrete columns was analyzed. The research indicates that the calculated values and experimental values of bearing capacity of confined concrete columns agree well, based on the coefficient of cross-sectional shape and longitudinal reinforcement distribution and that of cross-sectional shape and stirrup spacing which are introduced to describe the influence of stirrup spacing and longitudinal reinforcement spacing in Model Code 2010. It can broaden the provisions of the maximum stirrup spacing of confined concrete in GB 50010-2010 and ACI 318-14.