窄基输电塔分离式K型节点的受力性能试验研究

EXPERIMENTAL STUDY ON THE MECHANICAL BEHAVIOR OF DETACHED TUBULAR K-JOINTS OF NARROW FOUNDATION TRANSMISSION TOWERS

各国现行钢结构规范中,均未涉及小夹角(小于30°)K型钢管-节点板连接整体式和分离式节点的极限承载力计算方法。该研究通过对整体式和分离式25°K型钢管节点的承载力试验,探讨了该类节点的承载力-变形曲线和破坏模式,并对承载力、主管应变与节点板分离距离的关系进行了分析。研究表明,当节点板分离距离较小时,节点破坏模式为主管撕裂型剪切破坏,当节点板分离距离较大时,主管发生大变形压屈破坏;其次,节点板的分离导致承载力骤减,分离距离越大承载力越小。因此,虽然常规小夹角K型管-板节点存在节点板过长的问题,但是整体式节点板起到了良好的应力分散与传递作用。

In the current steel design code,the ultimate strength calculation methods of K-type steel tube-plate one-piece joints or detached joints with small angles(less than 30 degrees)are not involved.In this study,the load-deflection relations and failure modes of K-type steel tube plate one-piece joints and detached joints with small angles of 25 degrees were studied.The relations among the strength,the strain of the main steel tube and the dimensions of two gusset plates were analyzed.The results show that the main steel tube was teared and damaged in shear when the dimensions of the two gusset plates were small,while large deformation and compressive buckling of the main tube occurred when the dimensions of the two gusset plates were large.The separation of the gusset plate resulted in a sudden drop of the strength.The greater are the dimensions of the two gusset plates,the smaller is the strength.Therefore,the one-piece gusset plate has good stress dispersion and transmission although there is a problem that the gusset plate is too long in the conventional small-angle K-joints.