Research On The Ultimate Strength And Bending Rigidity Of Minor Axis T-sub Semi-rigid Connections

In the traditional analysis and design of steel frame structure, it was generally carried out under the assumptions as follows. The connections of beam and column were often assumed as completely rigid or ideally hinged. In fact, the stiffness of actual connections confirmed by observations and experiments are mostly between the two extreme conditions, completely rigid and ideally hinged. Semi-rigid connections have a considerable impact on the internal force, displacement and ultimate bearing capacity of the structure. T-stub connections, as a typical semi-rigid joint, have various advantages such as convenient construction and high industrialization and good ductility.In this paper, it presents minor axis T-stub semi-rigid connections and analyzes the ultimate bearing capacity of various components, then makes a comparison on the ultimate bearing capacity between them and selects the minimum value as the ultimate bearing capacity of the node, at last a set of models are calculated using the derived formula. On this basis, the paper analyses the initial rotational stiffness of the node and derives the initial rotational stiffness formula, then compiles a form to calculate a set of models, and the result shows that this kind of nodes are relatively semi-rigid connections. At the same time, the paper uses nonlinear finite element program ANSYS to study the ultimate bearing capacity and connection stiffness with various parameters. The results are showed as follows. The mostly important factors on the ultimate bearing capacity and the rotational stiffness of the connections are the cross-section height of columns and beams. When the column web thickness is less than T-stub beam flange thickness, the column web will yields at first under normal circumstances. But when the column web thickness is larger than T-stub beam flange thickness, the T-stub beam flange will yields at first, and at this time the deformation of column web and column flange are both quite small. The node capacity and rotational stiffness increase with the length of T-stub increasing and reduces with the width of T-stub increasing. But the effects of the width of column flange, thickness of T-stub beam web and diameter of high-strength bolts on the moment capacity and rotational stiffness of the connections are little. Finally, this paper uses the results data obtained from finite element analysis, derives the shape parameters of moment-rotation curve after calculating, and simulates the three-parameter power function curve of moment-rotation relationship of the connections.