A research program is presented to analyze the behaviour of rectangular hollow section (RHS) T-joints in the elasto-plastic range of loading. An attempt was made to obtain the joint ultimate and working strengths. The study includes the determination of both rotational and punching shear stiffnesses of the RHS T-joint due to applied moment and branch member axial loads respectively.
Two different joint types were analyzed, the unreinforced T-joint and the haunch reinforcement type. In both cases, the chord top flange was considered as a thin plate loaded on the perimeter of the rigid inclusion, and supported by coupled springs along its longitudinal edges, thus simulating the action of the side walls and connecting bottom flanges. Transverse from the joint, were taken as simple supported.
The finite element formulation that is proposed incorporates rectangular plate and boundary elements with springs. The model is then used to study elastic connections. The joint stiffness values are shown to be in good agreement with the experimental results available in the literature.
Finally, a study of the RHS T-joint behaviour under both axial load and applied moment, in the elastic-plastic range of loading, is presented. The sensitivity of joints to different geometric parameters of width ratio, λ, haunch size, λ₁, and chord thickness, t, for the entire range of loading is included. A prediction of the ultimate and working loads and moments that can be resisted by RHS T-joints, is given.