设分配梁巨型钢管混凝土柱轴压承载性能试验研究

分3批次完成了设分配梁传力构造的巨型钢管混凝土柱轴压系列试件,对3批试件的破坏模态、极限承载力、分配梁应变分布规律等进行综合对比分析.结果表明,通过分配梁传递给核心混凝土的竖向荷载大小与分配梁的横截面面积成正比,且远大于通过钢-混凝土黏结作用所传递的荷载,表明采用分配梁传递竖向荷载是高效、可行的.3批试件的分配梁均在梁端部区域形成了剪切屈服段,且当梁端形成剪切塑性铰后,分配梁传递给核心混凝土的竖向荷载基本维持不变,达到极限荷载时,分配梁两端发生剪切破坏.将内环板与分配梁结合设置,显著提高了分配梁传递竖向荷载的能力及试件的轴压极限承载能力.因此,在巨型钢管混凝土柱内设置分配梁传力构造,可有效促进钢管与混凝土共同工作,保障巨型钢管混凝土柱具有优越的轴压承载性能.

Experimental Investigation on Behavior of Giant Concrete Filled Steel Tubular Columns with Distributive Beam Under AxialCompression

A series of speciemens, including three batches, of giant concrete filled steel tubular columns (called giant CFT columns hereinafter) with detailings of distributive beam under axial load were completed. The failure mode, the load carrying capacity of specimens and the strain distribution on distributive beam of specimens were comprehensively compared and analyzed based on experimental results. It can be observed from the test results that the load shared by core concrete is proportional to the cross section area of distributive beam and is considerably larger than the load transmitted by the nature bond between steel tube and core concrete. Thereout, the conclusion could be drawn that the distributive beam set in giant CFT columns could transfer vertical load effectively and reliably. Meanwhile, the load transferred by distributive beam remained constant after shear plastic hinges at both ends of distributive beam were developed, and obvious plastic deformation from shear yielding to failure at the area of distributive beam ends could be observed. Finally, it could also be concluded from the results that giant CFT columns with both distributive beams and inner diaphragms gained much higher load bearing capacity than those only with distributive beams by comparing the two kinds of specimens. Therefore, co working performance between core concrete and steel tube could be effectively improved by distributive beam set in giant CFT columns, so that excellent axial load bearing behavior of giant CFT columns could be ensured.