ABSTRACT
Abstract A model of the strength of T-joints in Rectangular Hollow Sections (RHS) with f3 < 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 developed by the authors. The predicted interaction curve for the case where f3 = 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 f3 < 1.0 under combined bending and concentrated force. Keywords: Design, Failure, Load Combinations, Models, Tubes
The load capacity of an RHS connection is reduced by chord end loads (Wardenier (1982)). The effect of the axial compressive forces in the chord on the strength of T and K joints in RHS has been reported by CIDECT (1986). The effect of the bending moment in the chord on the strength of T-joints in RHS has been studied experimentally by Zhao and Hancqck (1991a). It was found by Zhao and Hancock (1991a) that for f3 = 1.0, the effect of the bending moment is so small that it needs not be taken into account. This is in agreement with the rules described in IIW (1989), Eurocode 3 (1992) and Packer et al (1992). It was also found by Zhao and Hancock (1991a) that for f3 = 0.5, the effect of the bending moment becomes significant when the-bending moment exceeds half of the fully plastic moment capacity of the section. The theoretical analysis for T-joints in RHS with f3 < 1.0 under concentrated force alone has been studied by Zhao and Hancock (1991b). The purpose of this paper is to study theoretically the interaction behaviour for T-joints in RHS with f3 < 1.0 under combined bending and concentrated force using plastic mechanism analyses.
