钢管混凝土斜交框筒节点试验研究

Experimental study on intersecting connections used in CFT diagrid frame tube

钢管混凝土斜交网格框筒的网格节点汇集了斜柱、环梁、径向梁等构件,其构造和应力分布较为复杂。为了改进该类节点的受力性能,针对工程实际,设计了核心区采用转换柱体与中央竖板相结合的节点构造形式,并以相贯的方式与斜柱连接。为研究此类节点的承载能力和破坏形态,验证节点构造的合理性,实现"强节点弱构件"的设计目标,进行了6个缩尺比为1∶5.5的柱倾斜45°的节点模型试验,在10 MN级自平衡钢结构加载架内,采用两个5 MN千斤顶对相贯节点的柱端施加轴向荷载。结果表明,节点设计符合"强节点弱构件"的设计要求,即使节点区混凝土浇筑不密实,节点的受力性能也能够达到设计要求,节点的设计方法可行,构造合理。

The intersecting connection of CFT diagrid frame tube connects members including inclined columns, ring beams and radial beams, etc. The construction and stress distribution are complicated. To improve the performance of such nodes, a new form of node is developed for such type of structure ： transferring cylinder with reinforcing central plate at core zone and connected to the inclined column by penetration welding junction. In order to verify the rationality of the connections and to investigate the performance, capacity, failure mechanism, and to assure that the capacity of connections can exceed that of structural members, six 1 ： 5.5 scaled models were tested using a self- balancing equipment with a 10 000 kN capacity loading frame. Two axial forces are applied at the end of inclined columns of diagrid nodes with 5 000 kN jacks. Test results indicate that node design conforms to the principle of ＇strong node weak component＇. Even if concrete at the node area is not poured densely, the node performance can also meet the design requirements, and the design method and construction detail are reliable.