巨型钢管混凝土柱分配梁构造下竖向荷载传递机理研究（I）：试验研究

在前期试验研究的基础上，对设置分配梁构造的超大截面矩形钢管混凝土柱进行轴压1∶5缩尺模型试验 研究。为考察分配梁构造对竖向荷载的传递机制，试验中竖向荷载仅通过加载梁施加于钢管壁，混凝土不直接承 担荷载。通过对试件破坏模式、分配梁破坏模式、管壁应变分布、试件承载性能及钢-混凝土共同工作性能进行 分析，结果表明：所有试件表现出良好的延性，根据试验竖向荷载-位移曲线得出试件达到峰值荷载前具有较长 的屈服平台段；混凝土承担的荷载取决于分配梁截面面积及截面刚度，并随分配梁截面面积的减小而降低；分配 梁破坏模式为在梁端产生剪切屈服区域并产生较大塑性变形，部分试件分配梁下翼缘及腹板处形成了贯通撕裂裂 缝；分配梁试验屈服承载力略大于梁全截面抗剪承载力，试验极限承载力接近梁全截面抗拉承载力。

Compression load transfer mechanism of distributive beam detailings in large-section CFT columns (I): experiment study

In order to investigate the load transfer mechanism of a new detailing, named distributive beam, in large rectangular section concrete-filled steel tubular columns, a series of 1∶5 scaled models were tested. The vertical load was applied on the steel tube directly in the test, so the core concrete was not directly loaded. The failure modes of specimens, the failure modes of distributive beam, the strain distribution of steel tube and the load-bearing capacity of specimens were analyzed. The cooperating performance of test specimens with distributive beam detailings was evaluated at last. The test results show that the specimens exhibit good ductility performance with an obvious yield platform before the ultimate load according to the experimental axial load-deformation relationships. The load shouldered by the concrete decreases with the decrease of the cross-section area of distributive beam. The failure of distributive beam occurs at beam end, where obvious plastic deformation is shown, and tear failure of the web and the bottom flange of distributive beam can be observed in some specimens. According to the analysis results, the yield capacity of distributive beam is larger than the full cross-section shear strength of the beam, while the ultimate capacity is close to the full cross-section tensile strength of the beam.