受多重约束的钢管内混凝土受力性能试验研究

利用已破坏的带有芯钢管的钢管混凝土节点试件,截取尚未破坏的节点区域,对其芯钢管内混凝土施加轴心压力。研究钢管内混凝土在多重约束下的受力性能和极限承载力,分析节点各组成部分对核心混凝土的多重约束作用。试验研究表明,受到多重约束的管内混凝土强度和变形能力有很大提高,若以极限承载力除以混凝土受荷面积,可得到约束混凝土强度为250 MPa左右。通过荷载-位移曲线的分析和约束混凝土受力机理的探讨,证明除约束混凝土外,通过混凝土与钢管的摩擦力及混凝土与钢管的粘结力传给钢管的竖向承载力,对试件的极限承载力也有贡献。

EXPERIMENT STUDY ON THE MECHANICAL PROPERTIES OF THE MULTI-CONSTRAINT CONCRETE IN THE STEEL TUBE

The joints of concrete filled steel tube with core steel tube were studied by loading the axial load in the core concrete.The joints were intercepted from the remanent joints specimens.The mechanical properties and the ultimate bearing capacity of the core concrete in multiply confined condition were studied and the constraint action of the joint components to core concrete was analyzed.The test results show that the strength and the deformation capacity of the core concrete are improved greatly.If the ultimate bearing capacity is divided by the area of loading,the compression strength of core concrete can be up to 250 MPa.According to the analyses of the loading-displacement curves and the bearing mechanisms to confined concrete,it proved that the force of friction between the concrete and the steel tube,the vertical force of the steel tube besides the confined concrete,have contribution to the ultimate bearing capacity.