T形钢管混凝土短柱轴压试验

进行了6根普通构造T形钢管混凝土轴压短柱的试验研究，以考察无加劲措施T形钢管混凝土柱的变形特征、破坏模式和承载能力.试验的主要参数有管壁宽厚比、截面高宽比.试验结果表明，由于 T形钢管混凝土柱的核心混凝土延缓了钢管的局部屈曲，尽管该组合构件承载力不能得到有效提高，但延性却得到相当改善；阳角钢管对混凝土提供了较强的约束，而由于钢板与混凝土的分离，阴角钢管几乎不能约束混凝土；T形钢管混凝土柱的破坏形态主要为钢管鼓曲及此部位及阴角区域混凝土压碎破坏；管壁宽厚比越小, 初始鼓曲发生越晚, 钢管对混凝土的约束效应越强，承载力越高、延性越好.最后采用现有规范或规程的计算公式对试件轴压承载力进行了计算，并对不同计算方法的适用性进行了探讨.
Tests were conducted on six concrete filled Tshaped steel tube (CFTST) stubs to investigate the characters of the deformation, failure modes and the bearing capacity of this kind of composite columns. The parameters taken into consideration in the test included the depth to thickness ratio of steel plates, the cross sectional depth to width ratio of the specimens. Experiment indicated that the bearing capacities of CFLST columns were not improved effectively, but the ductility were increased considerably, due to the fact that the local buckling mode of steel tubes were altered by the core concrete. It was also observed that the outward corners of steel tubes gave the greater confinement to concrete, and the inner corners almost failed to confine the core concrete due to the separation between the steel plate and the core concrete; hence CFTST stub columns failed in the local buckling of the wider steel plate and the crushing of concrete in the region of local buckling and inner corner. Test results showed that the decrease of the depth to thickness ratio of the flange plates of the steel tubes could postpone the occurrence of the initial local bucking in the wider steel plate, strengthen the confinement effects of steel tubes on concrete, and enhance the bearing capacity and ductility of the CFTST columns. Finally, the applicability of the methods in current specifications or codes, national and abroad, for calculating the bearing capacity of specimens was discussed