Research On Ultimate Bearing Capacity And Seismic Performance Of Large-size Box Type K-node

Steel structure buildings are the green environmental protection buildings and its seismic behavior were relatively superior, in practice project we often need to strengthen the steel tubular joints which its ultimate bearing capacity does not meet the requirements, for large size steel tubular joints are especially like this. Currently, the research on big size steel tubular joints is not sufficient compared with smaller size steel tubular joints. As for reinforced joints,such as big size box K-joint reinforced with rib stiffener researched by this paper, there is no ultimate bearing capacity formula in the current steel structure design code. There are many ways to strengthen the tube wall of joints such as with an outer pipe reinforced ? plate reinforced?flitch plate reinforced?rib stiffener reinforced, a nonlinear comparative analysis on big size box K-joint reinforced with above four reinforce method by large finite element software ABAQUS, the results showed that rib stiffener can improve the ultimate capacity of joints in the maximal degree.Based on verify the accuracy of Finite Element Model by test data, parametric analysis on big size box K-joint reinforced by rib stiffener were studied. The ultimate bearing capacity calculation formulas of big size box K-joint reinforced by rib stiffener under axial force ? in-plane oppose bending moment ? in-plane oppose bending moment are returned, the formulas are expression by two forms, to put forward some reference for engineering design. A comparative analysis of seismic behavior of big size box K-joints reinforced by four reinforce methods is studied by ABAQUS software. The results showed that rib stiffener reinforced method is better than other three methods in some aspects such as hysteretic curve?ductility coefficient?energy dissipation coefficient and other indexes.A further studied on the comparative analysis of seismic performance big size box K-joint reinforced by rib stiffener: the different width of rib stiffener?the different thickness of rib stiffener?the different number of rib stiffener?the different ratio of section width of main pipe and branch pipe ??the different angle between main pipe and branch pipe ??the different clearance between two branch pipe g, to research influence of various parameters on the seismic behavior. In short, the rib stiffener can not only greatly increase the ultimate bearing capacity of large size box-K-joints, but can greatly improve its seismic performance.