Structural analysis of diamond bird-beak joints subjected to compressive and tensile forces

• Diamond bird-beak (DBB) joints are structurally analysed.
• An experimentally validated numerical tool is used as a simulation tool.
• The DBB joints are both analysed when subjected to compressive and to tensile forces.
• A proposal aimed at predicting the ultimate load capacity of DBB joints is given.

Diamond bird beak RHS X-joints are deemed as being a type of welded X-joint between steel rectangular hollow sections in which both the chord and brace are rotated 45° around their longitudinal axes. This type of joints provides aesthetic appeal that encourages its usage in the increasing demand of trussed, tubular constructions worldwide. This paper presents a structural assessment of such joints when the members are subjected to compressive and to tensile forces. The study is performed with a nonlinear, finite-element based model from which a vast parametric study is developed. The results obtained for members subjected to compression are in good agreement with experimental results found in the literature as well as with other numerical studies with similar structural conditions. For members subjected to compressive forces but to different structural conditions from other models, the results show some discrepancies and a design proposal is presented. On the other hand, for members subjected to tensile forces, no prior studies were found in the literature. A design proposal aimed at predicting the ultimate load capacity of such members is given at the end of the paper.

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