The Research On The Behavior Of T-Stub Semi-Rigid Connections

People always treat beam-to-column connections as fully rigid or pinned ones to simplify the calculation of the steel frames in traditional designs. In fact, most of beam-to-column connections will be either pinned or fully rigid ones. They belong to semi-rigid ones. Extensive studies show that the behaviors of semi-rigid connections would make great effects on the behaviors of steel frames such as the internal forces, the horizontal deflection and the ultimate load-bearing capacity, which could not be neglected to design the steel frames.In this paper, the ultimate load-bearing capacities of the T-stub connections that are regarded as semi-rigid ones applied in factual projects are calculated. Compared with the ultimate load-bearing capacity of its components, the minimum is what we need. In this way, six different specimens' models of the connections are calculated. Meanwhile, the calculation method of its moment-rotation relationship is presented. Based on this method, the moment-rotation relationship of those models are calculated and imitated with the three-parameter power model. The results show that T-stub connections are semi-rigid ones and its behaviors are affected by several factors of its components. In the same time, the effects of components on its behaviors are studied by means of the nonlinear finite element method. The results show that the thickness of flange of the column and the T-stub and the vertical interval of bolts greatly influence the behaviors of the connections, while, the thickness of the column and the T-stub's web and the horizontal interval of bolts have little influence on its behaviors. The theoretical analysis about plane steel frames with semi-rigid connections also is done based on the characteristics of semi-rigid connections. In this way, the stiffness matrix of the frames is inferred, and the formula of the fixed moment calculation about beam element with semi-rigid connections is presented. In order to simplify the calculation, hand calculation methods of the internal forces and the horizontal deflection about the frames are proposed. Numerical results show that the presented method is reliable and is helpful to engineers in structural design. Finally, some suggestions about the design of T-stub connections are proposed.