Analysis Of Mechanical Properties Of High Strength Cold-Formed Thin-wall Steel Truss Beam Floor System

Cold-formed thin-wall steel construction house is a kind of house structural system of low carbon, environmental protection, energy conservation, whose construction members can be produced with standardization, canalization and factorization, it is one of the structural systems that instead of traditional structures. Research of this residential system has important significance in sustainable development of our national economy and improving people’s living conditions.In this paper, smart low-rise light steel residential system of Wuhan Met Frame Construction Technology CO.LTD was taken as the research background and the high-strength cold-formed thin wall steel truss beam floor system was taken as the research object. The material yield strength of the high strength cold-formed thin-wall steel is550MPa.h Three aspects was discussed about mechanical performance of the high strength cold-formed steel truss beam floor system which constituted by high strength cold-formed steel truss beam and surface layer material.(1) The buckling mode and the ultimate bearing capacity under uniformly distributed loads have been analyzed by the finite element software ABAQUS, researched the effects of truss beam and failure modes caused by the factors including the chord wall thickness, beam height, initial imperfections. The results indicated that the ultra-thin-wall and open sections of the member is the main reason of local buckling and distortional buckling in truss beam; the geometric initial imperfections have little effect to the ultimate bearing capacity and failure mode; the beam wall thickness increases have little effects to the ultimate bearing capacity of the beam, but it can reduce the truss chord open deformation effective; The increase height of the truss beam can significantly improve the ultimate bearing capacity, but would cause the brittle failure;(2) Considering the needs of project, the mechanical performance of the floor system caused by truss beam specimens, truss beam spacing, OSB plate thickness. The results indicated that the change of truss beam specimens and distance have obvious affects to the overall effects truss beam influence, while due to specification limits the OSB plate thickness has small influence to the whole floor;(3) The relationship and the difference between single truss beam and whole floor system in stability, ultimate strength and failure modes are comparatively analyzed, the results show that the capacity improvement multiples of truss beam floor system is greater than number increasing of single truss beam, and the mid-span displacement of the floor system is limited well, OSB slab showed good performance in limiting the deformation of the outer sheets of the truss beam and reducing the stress level of upper chord, which reflected the overall effect of the floor system. And whether a single truss beam or floor system, larger stress level displayed in its end diagonal web member, and the end diagonal web members can be replaced with closed-section members or increase the wall thickness of the member in order to improve its mechanical performance.