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以国家电网公司应用Q420高强钢首批输电线路试点工程（500kV汉江大跨越直线塔主材采用Q420钢管）为背景,对3种类型的K型相贯节点进行了足尺试验研究.试验表明,在主管轴力较高时,节点的破坏以主管的局部塑性变形破坏为主,节点的破坏很大程度是由节点域主管的变形来表现的;K3型节点加劲板的设置,能有效地将两支管上的力均匀传给主管,从而改善节点支管与主管相贯线区域的受力性能,这就是K3型节点的实测承载力较K2型节点提高了25%的原因.借用中国钢结构设计规范中的计算方法进行了比较和推析,发现对K型高强钢节点简单地套用现有的简化公式和计算公式不可取.“,”The high-strength steel pipe Q420 has been experimented through pilot projects by the state Grid Company of China when applied to the large-span Hanjiang river-crossing towers for 500 kV transmission lines with the high-strength steel pipe Q420 as main members.Full scale tests on six K-shaped nodes specimens are carried out for three types.The test results indicate that under high axial force,local plastic deformation of the chord may become the main failure mode of K-joints.It is shown that the deformation of chord in region responds a lot to the failure.Installation of stiffened plate in K3-joints can transferr the load from branch to chord effectively,so as to improve the mechanical performance of structure in joint region.It is reason that the ulimate capacity of K3-joint is higner than that of K2-joint by 25%.Moreover,these results are compared with that calculated according to the Chinese National Code for Design of Steel Structures GB50017-2003,it is found out that the existing formula cannot be applied mechanically to K-type high strength steel node.