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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。
Based on the previous experimental studies, a 1: 5 scale model test of large-section rectangular CFST columns with distribution beam structure was carried out. In order to investigate the transmission mechanism of the distribution beam structure to the vertical load, in the test, the vertical load is applied to the steel pipe wall only through the loading beam, and the concrete does not directly bear the load. The failure mode of the test piece, failure mode of the distribution beam, strain distribution of the pipe wall, bearing capacity of the test piece and common work performance of the steel-concrete are analyzed. The results show that all the test pieces show good ductility. According to the vertical load- The curve shows that there is a long yielding platform before the peak load of the specimen. The load of the concrete depends on the sectional area and the section stiffness of the distribution beam and decreases with the decrease of the sectional area of the distribution beam. The yielding shear yielding area at the end and the plastic deformation are larger, and the tear propagation cracks are formed in the flanges and webs of some specimens; the yield strength of the distribution beam is slightly larger than the shear capacity of the full beam, Bearing capacity close to the full cross-section tensile load capacity.