钢管混凝土双肢中柱双层肩梁单向加载试验及肩梁承载力计算模型

UNIAXIAL LOADING TESTS AND THE CALCULATION MODEL OF THE BEARING CAPACITY FOR DOUBLE-LAYER SHOULDER BEAMS WITH DOUBLE-LIMB MIDDLE COLUMNS OF CONCRETE-FILLED STEEL TUBES

针对一种新型的钢管混凝土双肢中柱双层肩梁构造形式,通过对两个试件进行平面内单方向加载试验,研究试件的破坏过程、破坏模式、应变分布。结果表明:在水平力作用下,荷载大部分传至试件的下层肩梁,最终在下层肩梁受压区格腹板处发生剪切破坏,试件的延性非常好,试件水平承载力很大程度上取决于下层肩梁腹板截面;试件的上、下层肩梁腹板的承载力主要受切应变控制,焊缝附近的应变分布与理论所得应变分布不同;肩梁翼缘处存在应变集中现象。基于分析结果,提出钢管混凝土双肢中柱双层肩梁水平承载力计算模型及算式。

Targeted at a new type of double-layer shoulder beams with double-limb middle columns of concrete-filled steel tubes(CFST),the failure process,failure mode and strain distribution of two specimens were studied by in-plane uniaxial loading test.The results showed that under the action of horizontal forces,most of the load was transferred to the lower shoulder beam of specimens,and finally shear failure occured at the grid web in the compression zone of the lower shoulder beam.The ductility of specimens was excellent,and the horizontal bearing capacity of specimens largely depended on the section of the web for the lower shoulder beam;the shear strain was mainly controlled by the upper and lower webs of the shoulder beam for specimens,and the strain distribution near the weld joint was different from that obtained by theory.The strain concentration existed at the flange of the shoulder beam.Based on the analysis results,the calculation model and formula for the horizontal bearing capacity of the double-layer shoulder beam with double-limb middle columns of concrete-filled steel tubes were proposed.