Experiment Research And Analysis On Lightweight Steel Structure Of Integra Building System

Lightweght steel structures are higher strength and durability, superior aseismic performance lightweight for easy handing and lower costs, manufactured to exacting standards to produce pre cut lengths and angles, also able to withstand most environmental conditions that can qualify for lower fire insurance premiums. In recent 10 years these systems are developed rapidely in China. In this paper, the Integra building system (IBS) which is a web light gauge steel system is introduced. The bearing capacity, deflection, failure modes and dynamic performance of its member, shear wall and structure system are researched based on experiments for its codes of design and construction.The bearing capacity, failure modes, deformation, bend stiffness in plane and out plane of floor joist are tested by 13 floor joist specimens. The results suggest that a single foor joist is not suitable for bearing loads for its lower ultimate bearing capacity and stiffness out plane, the stabiliy bearing capacity can be improved with larger cross section of up-tube of joist floor. Compare with test results the finite element analysis (FEA) models of joist floor are rational. Parameters which have effect on bearing capacity and deflection of mid-span are investigated by FEA. Corss section of up-tube of floor joist has most effect on its ultimate bearing capacity. With larger cross section of up-tube, the ultimate bearing capacity and stiffness are higher. Upside-down clips in members can decrease ultimate bearing capacity. Large clips can improve ultimate bearing capacity, reduce deflection of mid-span and increase its bending stiffness.The ultimate bearing capacity and failure modes of studs and box columns are studied with 6 spcimens which bear axis press loads. The data suggest that its ultimate bearing capacity is lower, its can not use alone as structure member.9 connnection specimens (3 types) have been studied for the deformation, strain and ultimate bearing capacity under each level load. Based on the result, detail means for improving stiffness of connections are bring forward. The connections are modeled in finite element analysis software; the results of FEA are closed to data of experiment for specimens. Three type M-θcurves are given for IBS connections.Vertical bearing capacity, lateral bearing capacity, deformation and failure modes of IBS wall are researched through 5 specimen which bear veritical load and 10 ones which bear lateral load. Experiment result shows that bearing capacity of these walls without sheathing is lower. More horizontal and "X" bracing, more bearing capacity is, but more steel need. But veritical bearing capacity of IBS wall with seathing is higer, deformation is less. Intensity of steel is brought into sufficient play, and failure of wall with sheathing is strength one. Lateral load is beared mainly by diagonal tension straps; window and door opening in the wall have serious effect on its bearing capacity. The wall with seathing has suporier lateral performance and structure integrity, and its deformation is not more shear type under lateral loads.Parameters effect on veritical bearing capacity of IBS wall with sheathing and without seathing have been instigated by FEA, the most important factor effect on veritical bearing capacity of wall is sheathing, next is high, thickness of wall and number of horizontal bracing. Design method of veritical bearing capacity is brought forward. The result of FEA shows that lateral capacity of wall with bamboo glue panel is higher than one of wall with OSB panel and gypsum panel, and more thickness, number of sheathing, cross section of diagonal tension steel strap and less span between studs in wall, more lateral capacity the wall has.Based on study of mainly factors effect on shear strength and shear stiffness and its simplified formulas for general light gauge steel structure, these formulas for IBS wall are put forward.Shaking table test and dynamic analysis of a full size two-layer model is performed. Dynamic characteristic of the model and dynamic response under various wave excitations input are studied. Finite element method is used for dynamic analysis of this model, these results are close and can provide relative data and reference.