Plastic mechanism analysis of t-joints in RHS subject to combined bending and concentrated force

Joints can occur in tubular structures where the main member is subjected to a bending moment rather than an axial force, particularly for rigid jointed frames. A model of the strength of T-joints in Rectangular Hollow Sections (RHS) with β < 1.0 subject to combined bending and concentrated force is developed based on experimental observations of joint tests performed by the authors. The action in the chord (moment) rather than the chord normal stress is used in the development of the interaction curves. The reduction of the plastic moment capacity of inclined yield lines under axial force is considered in the study. This reduction is based on a new model for inclined yield lines under axial force recently developed by the authors. The predicted interaction curve for the case where β = 0.5 is compared with test results of the authors. A design formula is derived based on the plastic mechanism analysis for T-joints with β < 1.0 under combined bending and concentrated force.