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为分析钢管混凝土桁式拱结构的受力性能和破坏形态,进行了钢管混凝土桁式拱模型的试验研究。结果表明:钢管混凝土桁式拱结构节间直腹杆受到较大的竖向力,产生塑性变形,且随着竖向力的增大,直腹杆塑性变形节间增多,塑性变形区域沿拱轴向发展,内力重分布;在达到极限荷载前,桁式拱表现出了较好的整体性,没有出现节点破坏;达到极限荷载时,跨中至四分点附近截面处的节间直腹杆端部屈曲;继续加载后斜腹杆出现端部剪切破坏,最后弦管出现压弯失稳破坏;试验全过程中,桁式拱结构各弦管均未出现开裂现象,也未出现焊接节点或相贯区域破坏。同时,在试验研究的基础上,分析比较了钢管混凝土桁式拱结构、桁梁以及格构柱的受力特性和破坏形态,结果表明,钢管混凝土桁式拱结构的破坏模式与格构柱和桁梁存在较大的不同,桁式拱节间直腹杆受到较大的竖向力,因此,建议实际工程中应对钢管混凝土桁式拱腹杆的受力进行计算与校验。
In order to analyze the mechanical behavior and failure mode of CFST truss arch structure, the experimental study of CFST truss arch model was carried out. The results show that the straight webs of CFST truss arch structures are subjected to large vertical force and plastic deformation. With the increase of vertical force, the plastic deformation internals of straight webs increase, and the plastic deformation area along the arch Axial development and internal force redistribution; Before reaching the ultimate load, the truss arch showed a better integrity without node failure. When the ultimate load was reached, the internodes between the middle and the quarter points were straight The buckling of the end of the rod was continued, the shear failure of the end of the web was observed after the loading continued, and the buckling instability of the chord was finally occurred. In the whole process of the test, no cracking occurred in the chords of the trussed arch structure and no welding occurred Nodes or areas of intersection damage. At the same time, based on the experimental study, the mechanical behaviors and failure modes of CFST truss arch, truss girder and lattice column are analyzed and compared. The results show that the failure mode of CFST truss arch structure is similar to that of the lattice column and There is a big difference between the truss girders, and the straight webs between the truss arch sections are subject to a large vertical force. Therefore, it is suggested that the calculation and verification of the force of the CFST truss webs in the actual project should be carried out.