角钢约束混凝土中长柱轴压力学性能试验及承载力计算

为了研究角钢约束混凝土中长柱在轴压荷载作用下的力学性能,以长细比、缀板间距、混凝土强度等级为变化参数,完成了8个试件的静力加载试验。通过试验观察了试件的破坏形态,获取了其极限承载力、刚度、位移延性和耗能系数等力学性能指标;分析了各变化参数对力学性能指标的影响,利用统一强度理论、极限理论和叠加理论对试件的承载力进行计算。研究结果表明:长细比越小越容易发生柱端破坏,长细比加大后易发生柱中破坏;减小缀板间距,试件的极限承载力和变形能力均得到提高。随着混凝土强度等级的提高,试件的极限承载能力和初始弹性刚度得以提高,但位移延性和耗能能力有所降低。采用统一强度理论的计算值略大于试验值,采用极限分析理论和叠加理论的计算值均小于试验值。

Mechanical Performance Experiment and Bearing Capacity Calculation of Middle Long Columns Made of Angle Steel Restrained Concrete and Subjected to Axial Compression

In order to study the mechanical properties of middle long column made of angle steel restrained concrete and subjected to axial compression, taking slenderness ratio, batten plate spacing and concrete strength as experimental parameters, static loading experiment for 8 middle long column specimens was carried out. Through experiment, the failure mode of specimen was observed, its main mechanical indices, such as ultimate bearing capacity, stiffness, displacement ductility and energy dissipation coefficient were obtained. The influence of above parameters on mechanical property indices of specimen was analyzed. The bearing capacity of specimen was calculated and analyzed based on unified strength theory, limit theory and superposition theory respectively. Results show that columns with small slenderness ratio are prone to be damaged on its end, and columns with larger slenderness ratio are prone to be damaged at column middle; the smaller the batten plate spacing is, the greater the ultimate bearing capacity and deformation capacity are; with the concrete strength increase, the ultimate bearing capacity and initial elastic stiffness increase but both displacement ductility and energy dissipation capacity decrease. The calculated values from unified strength theory are slightly larger than experimental results, while the calculated values from both limit theory and superposition theory are smaller than experimental results.