Theoretical Analysis of T-Joints in Hollow Structural Sections

Abstract

<p>A research program is presented to analyse the behaviour of the T-joints between square (or rectangular) HSS in the elastic range. An attempt was made to obtain the joint rigidity in both cases of loading, applied moment and branch member axial loads.</p> <p>Two different joint types were analysed, unreinforced T-joint as well as the haunch reinforcement type. In each case, the chord top flange was considered as a thin pIate loaded on the perimeter of a rigid inclusion.</p> <p>A theoretical model was established for the chord member to describe the continuity between the top flange plate with the chord webs, and to permit the introduction of elastically restrained edges for deflection as well as rotation.</p> <p>The finite difference method was used together with a variety of edge boundary conditions to study the effect of the width ratio λ, the haunch size parameter λ₁ and the width-thickness ratio b/t.</p> <p>The joint stiffness values (axial and bending) were obtained theoretically for 80 different joint sizes with 5 different edge conditions for the chord plate. A comparison with the available experimental and other theoretical results is also presented.</p> <p>The main contribution in the study was the theoretical analysis presented for the haunch type connection, which has not been done previously.</p> <p>An elastic stress analysis was also conducted to define limits for the working loads that may be applied to the joints without incurring yielding in the chord member.</p> <p>The theoretical study confirms the results of tests that the unequal width unreinforced connection is generally too weak to be viable practically. However, the haunch connection, while not as "aesthetically attractive as the unreinforced type, has adequate strength and stiffness for most applications.</p>