Study On The Mechanical Properties Of The Steel Staggered-truss System Under The Cyclic Loading

Steel staggered-truss system is used in the Multi-high Building such as hotel and residence. At present, domestic and international scholars carried out a series of theoretical analysis on such a system, and it has been applied abroad widely. But a lot of research is mainly concentrated in the integrality performance, while little research is on the structure component such as braces. Embarking from the holistic resistant behavior of the steel staggered-truss system, this paper thoroughly researched the mechanical behavior of the braces in steel staggered-truss system. It has the extremely important practical significance regarding the instruction design work and the widely appliance of the steel staggered-truss system.This paper applies material nonlinear and geometry nonlinear finite element method(FEM)to thoroughly analyze the bearing capacity, stiffness, stress distribution, energy dissipation and braces' force of the steel staggered-truss system in the monotonic loading and cyclic loading. The main conclusions were got:(1)In the monotonic loading, the both ends of the braces which connected the gusset plates are firstly into the plastic region and further developed to be a plastic hinge. The stress of the ends of the braces is much lager than the central region's, and the ends of the braces have the obvious stress concentration.(2)In the cyclic loading, the staggered truss system's hysteresis curve is fusiform, full and stability with good energy dissipation.(3)The week location is the central section without web members of the middle frame in the staggered-truss system, and the obvious stress concentration is became at the both ends of the braces, so the braces' strength and stability should be checked.(4)Hybrid staggered-truss system is different from the ordinary truss. Its braces are not simple axial force components, the strength and stability of the vertical braces should be checked as flexure and compression members, while the strength of the diagonal braces should be checked as the eccentric component.(5)Shortening the distance of the central section which has no web members in the hybrid steel staggered-truss system can improve the load-carrying capacity of the structure.The load-bearing performance of the gussets of the steel staggered-truss constructions is analyzed exactly in this paper. The work and the result are very useful for revising design specifications and guiding design of engineering. This paper will play a basic role in the further study on steel staggered-truss constructions.