Buckling resistance of angle bracing members with one‐leg bolted end connections

Steel angle members are widely used for the construction of lattice towers, mainly because of easy assembly on site and compact transport. Bracing members, especially, are connected directly or through gusset plates to the adjacent members with one or more bolts on one leg only. This type of connection provides some rotational restraint at the ends of the bracing, but also induces eccentricities. This paper presents the European normative framework covering the design against buckling of angle bracing members in lattice towers and identifies the differences between the different design rules available in existing normative documents. These differences are quantified through worked examples and the normative design procedures are evaluated against experimental results from the literature. The influence on the buckling resistance of various parameters, such as the support conditions and the steel grade, covering members made of both conventional mild steel as well as high strength (S460) steel, is also studied and quantified. Finally, useful conclusions are drawn about the accuracy of the available design rules.