不同受力状态下N型圆钢管完全搭接节点力学性能研究

Research on the mechanical behavior of totally overlapped tubular N-joints under different load case

对正反对称Pratt桁架中出现的直腹杆受压及直腹杆受拉N型圆钢管完全搭接节点的静力性能进行了单调加载的试验研究.实施了1个直腹杆受压和1个直腹杆受拉N型圆钢管完全搭接节点试验.试验研究结果表明:直腹杆受压的破坏模式为直腹杆平面外倾斜及斜腹杆管壁表面塑性,直腹杆受拉的破坏模式为弦杆管壁与斜腹杆管壁表面塑性及母材开裂;欧3规范较中国规范精度更高,且直腹杆受压时中国规范偏于不安全;直腹杆受拉情况下节点承载力性能优于直腹杆受压情况下,极限承载力提高近42%.

The static behavior of totally overlapped tubular N-joints with vertical brace under compression in sym-metrical Pratt truss and vertical brace under stretch in anti-symmetrical Pratt truss were studied. One vertical brace under compression and one vertical brace under stretch were tested under monotonic loading. Results of these tests showed that the failure of model vertical brace under compression was the combined failure of the vertical brace incline and slant brace face plastification, and the failure of model vertical brace under stretch was the combined failure of the chord and slant brace face plastification and base material crack. The calculation showed that the result obtained from Euroeode 3 is more accurate than the China code which turns out unsafe in vertical brace under compression;the ultimate capacity of joints in vertical brace under stretch which is higher than vertical brace under compression raised by 42%.