平面KK型矩形钢管节点静力试验研究

Study on static test of planar KK⁃type rectangular hollow section steel joints

依托某主题广场月牙形艺廊单层网壳钢屋架结构,选取其最不利受力节点,设计了中心插板节点和毂节点两种KK型矩形钢管节点,分别对其足尺模型进行静载试验,测试分析模型节点区域的应变及应力分布规律,对比分析支管端部的位移变化。结果表明:1)设计荷载水平下,两个节点均满足受力要求;毂节点和中心插板节点的最大试验荷载约为等效设计荷载的2.85倍和3.25倍,节点安全储备较高;2)在最大试验荷载作用下,两个节点支管根部与中心构件相贯焊缝附近部分均不同程度地屈服,毂节点圆筒内加劲肋焊缝局部出现开裂;3)相同荷载作用下,中心插板节点相应位置应力应变水平相对较低,故中心插板节点的承载强度较高;4)由试验荷载-位移曲线分析得出毂节点的各肢平均位移比中心插板节点约大13.3%,表明中心插板节点弹性刚度较大。

Based on the single-layer reticulated shell steel roof of a theme square crescent gallery,a typical joint with the most unfavorable stress were selected,and two KK-type RHS(rectangular hollow section)steel joints,i.e.,the center plate joint and the hub joint were designed.The two full-scale models were conducted static load and tested.The strain and stress distribution law in the joints area of the models were measured and analyzed,and the deformations at the end of the branch tubes were also measured and comparatively analyzed.The results show that:1)Under the design load level,both joints meet the strength deign requirement;and the maximum test loads of the hub joint and the center plate joint are respectively about 285 and 325 times of the equivalent design load.The two joints have high safety redundancy.2)Under the action of the maximum test load,the root of both nodal branches exhibited varying degrees of yielding in the vicinity of the coherent weld with the center member.The weld of one stiffener in the cylinder of the hub joint is partially cracked.3)Under the action of the same load,the measured stresses and strains of the center plate joint is relatively lower than those of the hub joint,so the bearing strength of the center plate joint is relatively higher.4)According to the measured load-deformation curve,the average displacement of each tube of the hub joint is about 133%larger than that of the central plate joint,which indicates that the central plate joint has higher elastic stiffness.