Study On The Mechanical Behavior Of The Gusset Plate In Staggered-truss Structure Systems Under 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 web members and gusset plates. Embarking from the holistic resistant behavior of the steel staggered-truss system, this paper thoroughly researched the mechanical behavior of the gusset plate in steel staggered-truss system, in order to improve the joint form in the new structure 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 mechanical behavior of the joint in steel staggered-truss system and exactly simulate the stressing state under various load-bearing conditions. This paper mainly research the mechanical behavior and the stress distribution under monotonic loading and cyclical-loading and research the effect of load form, load size, the free length through web member of the gusset plate, the distance of middle section to the mechanical behavior of the joint through the calculation and analysis of 19 species of 5 series of plates. The main conclusions are: The week location is the central section without web members of the middle frame in the staggered-truss system; In the hybrid staggered-truss system, the vertical web member is calculate as compression-bending member and the diagonal web member is calculate as member under an Eccentric Axial Force; The stress of the gusset plate under cyclical-loading is larger than under monotonic loading, and the gusset plate is very important to the seism-resist behavior of the whole system; Because the gusset plate of the hybrid steel staggered-truss system takes on stress concentration at the place where the web members are between little distance, and this phenomena will further develop if the distance is shortened, so the design can consider these methods such as increasing the angle between the web members, or increasing the distance of the web member and the chord; Increasing the free length of the gusset plate along the web members can improve the phenomena of the stress centralize, but it also be controlled by the thickness of plate in order to avoid the destroy without stability. 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.In conclusion, the FEM Model can well simulate the load-bearing behavior of the steel staggered-truss constructions. The load-bearing performance of the gussets 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.