中文摘要：

为了解主管内填混凝土对矩形钢管桁架受力性能的影响，在试验研究的基础上，进行了主管内填混凝土对矩形钢管桁架结构节点、杆件承载力和刚度的影响分析，并探讨了其失效机理。结果显示：主管内填混凝土改变了节点的失效模式，但节点仍然是桁架结构的薄弱部位；主管内填混凝土能够明显提高受压节点的承载力和刚度，但受拉节点的承载力和刚度提高程度不明显；主管内填混凝土能够很好地协助受压主管受力，并提高受压主管刚度，而受拉主管的承载力和刚度提高程度不明显；对受压支管承载力有一定影响，而对受拉支管影响很小。探讨了目前规程关于受压节点的破坏模式和承载力计算，以及主管内填混凝土后的矩形钢管桁架结构变形的计算，提出了考虑节点变形影响的实用计算方法，为主管内填混凝土矩形钢管桁架结构的应用提供参考。

英文摘要：

In order to reveal the effect of concrete-filled chord tubes on the behavior and failure mechanism of rectangular hollow section （RHS） steel tubular trusses, based on the experimental results, the effect of concrete-filled chord members on connections and members, as well as the failure modes, bearing capacity and structural stiffness is analyzed in this paper. The results show that the connections are still the weak points after chord members are filled with concrete, although their failure mode are very different ; the bearing capacity and stiffness of the joints subjected to compression load are increased significantly, but there is no obvious increase for those of the tension joints; the concrete-filled compression chord tube can increase the bearing capacity and stiffness significantly,while the effect of the tension chord tube is not obvious; the concrete-filled chord tubes have some influence on the bearing capacity of compressive branches, but no influence on tension branchs. Finally, based on the results, the failure modes of the compressive joint and the formulas to calculate its bearing capacity provided by current building code are discussed. Meanwhile, two methods, the amplified factor method and the stiffness discounting method, which calculate the structural displacement when considering the effect of joint deformation are presented, and are helpful for the engineers to design RHS steel tubular trusses.