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为分析方钢管加强节点的轴压承载能力和破坏模式,对支管与主管宽度比β=0.4和β=0.8的两组覆板加强节点、竖向插板加强节点进行轴向静力加载试验。分析了节点破坏模式、荷载-位移曲线、主管变形及应变,以及加强节点的受压承载机理。结果表明:在支管轴向压力作用下,未加强及加强节点的变形能力都较好,试件在破坏前有充分的塑性发展;覆板及插板加强节点的受压承载能力较对应的未加强试件有显著提高,当β=0.4时加强节点的破坏模式与未加强节点一致,当β=0.8时存在节点过度加强问题,引起支管先于节点破坏;相同β下,覆板加强节点的受压承载力高于竖向插板加强节点;在主管表面屈服破坏控制的情况下,覆板加强节点的承载机理为覆板与主管上翼缘共同屈服,竖向插板加强节点的承载机理为插板扩大了主管上、下翼缘的屈服范围。
In order to analyze the axial compressive load capacity and failure mode of the square steel tube joints, axial static loading tests were carried out on two sets of sheathing reinforcement nodes and vertical slab stiffeners with branch width ratio of β = 0.4 and β = 0.8. The failure mode, load-displacement curve, deformation and strain of the main pipe and the bearing mechanism of the node are analyzed. The results show that under the axial pressure of the branch pipe, the deformability of the unbonded and strengthened joints is good, and the specimens have adequate plasticity before failure. Whenβ = 0.4, the failure modes of the strengthened joints are the same as those of the un-strengthened joints. When β = 0.8, there exists the problem of excessive strengthening of the joints, which leads to the damage of the branch pipe before the joint. At the same β, Under the condition of superficial yield failure control of main pipe, the bearing mechanism of the strengthened joints of the superstructure is that the superstructure plate and the upper pipe flange yield together, and the vertical flapper strengthens the bearing mechanism of the joints Expand for the flapper in charge of the upper and lower flange yield range.