矩形钢管混凝土大跨度带悬挑桁架的试验研究

矩形钢管混凝土桁架能充分发挥钢管混凝土的受力性能，是适用于大跨度结构的结构形式。本文通过对2个大尺寸的大跨带悬挑矩形钢管混凝土桁架和矩形钢管桁架模型对比试验，考察了该桁架结构的破坏形态、变形特点和承载性能。试验结果表明，填充混凝土的钢管混凝土桁架试件的刚度提高、变形减小，极限承载力也有所提高，填充混凝土可以有效防止受压钢管壁的局部屈曲，试件破坏受材料的强度控制；采用直接焊接节点连接的钢管桁架和钢管混凝土桁架中腹杆和弦杆在节点处的杆端弯距较大，其对节点承载力的影响不可忽略，在设计中应加以考虑。

Exerimental Investigation of Concrete Filled Rectangular Steel Tubular Truss with Longer-span Cantilever Truss

Concrete filled rectangular steel tubular (CFRST) truss can bring the excellent behavior of concrete filled steel tubular into fall play, so it is a good structure type to use in long-span structure. Through the comparing experiments of two large specimens of CFRST truss and the rectangular steel tubular (RST) truss, the behavior, such as the destroy mode, the deformation and the ultimate strength of CFRST truss with longer-span cantilever CFRST truss is investigated. The experimental results show that for the CFRST truss the stiffness and the ultimate strength are larger and the deflection is smaller comparing with the RST truss, and that for the CFRST truss the filled concrete can effectively prevent the local buckling of the compressive steel tube, and then the destroy mode of the truss is controlled by intensity. The moments of the chord member and the web member at the node where the members are connected by directly welding are quite large. The effect of the moment on the ultimate strength of the node of the truss can not be ignored, which should be considered in design.