N型圆钢管相贯节点力学性能的试验研究

Experimental study of the static behavior of tubular N-joints

对承受支管轴力和主管轴力的N型圆钢管相贯节点、垫板加强节点、主管填充混凝土节点、主管填充混凝土和垫板加强节点试件进行了试验研究。综合比较了4种节点在破坏模式、受压支管荷载-主管管壁变形关系、主管管壁等效应力分布和极限承载力等方面的差异。试验结果表明,不同加强措施导致不同的节点破坏模式。填充混凝土能显著提高节点极限承载力,而加垫板提高幅度不大,但当主管径向刚度已经很大时,对主管加垫板可能反而降低节点的极限承载力。运用有限元方法对试验节点进行了非线性分析,得到了各试验节点的破坏模式、极限承载力、荷载-变形过程并与试验结果进行了比较。结果显示,二者吻合较好。

An experimental study was carried out on a tubular filled tubular N-joint, and a N-joint reinforced by concrete and N-joint, a plate reinforced tubular N-joint, a concrete plate under the axial compression of brace and chord. Test results, including the failure modes, the relationship between load in the compressive brace and deformation in the tubular wall of chord, the equivalent stress distribution in tubular wall of the chord and the ultimate capacity, were compared between the four joints, which indicates that different reinforcement methods can lead to different failure modes, the ultimate capacity of the joints can be remarkably enhanced by filling concrete in chord and can be only enhanced to a certain extent by welding a reinforce plate on the tubular wall of the chord, while welding a reinforcement plate on the tubular wall of the chord may weaken the ultimate capacity of the joint when the radial stiffness of the chord is sufficient. Nonlinear finite element analysis of the experimental joints was conducted. The failure mode, the ultimate capacity, and the full loading-displacement path were obtained and compared with the experimental results, and there was a good agreement between the experimental and the numerical results.