用外加劲肋加固T型圆钢管节点的试验研究

Experimental study on strength of CHS T-joints strengthened by external stiffeners

T型圆钢管节点主管轴向刚度较大,径向刚度较小,当通过支管向主管传递轴向力时,往往因为主管节点处径向承载力不够而发生较大变形甚至破坏,造成对支管强度的浪费。本文提出用外加劲肋加固T型节点,材料和施工成本较低。通过3组不同支管主管外径比的T型圆钢管节点承载力对比试验的研究,结果表明:由于外加劲肋的支撑,加固后的节点塑性区域扩大,节点极限承载力和变形能力提高,但极限承载力和变形能力的增幅随支管与主管外径比的增大而降低。工程中应根据不同支管与主管外径比,合理选择加劲肋尺寸。

The circular hollow section( CHS) T-joint has high chord axial stiffness,but low chord radial stiffness. When the axial load is transferred from the brace to the chord,large deformation and even joint failure may occur due to the deficiency of the chord radial bearing capacity at the joint intersection,resulting in the waste of brace bearing capacity.In this work,a strengthening method of using external stiffeners for CHS T-joints is proposed with low demand in material and construction costs. Comparative experiments on three sets of T-joints with different brace /chord diameter ratios are carried out. The results show that due to the support of external stiffeners,the plastic zones of strengthened joints expand,and the joint strengths and deformation capacities are enhanced,but the growth of joint strength and deformation capacity decreases with the brace /chord diameter ratio. In engineering practice,the size of stiffener should be appropriately determined according to the brace /chord diameter ratio.