1.1 General This International Standard gives recommendations for the design and analysis of unstiffened, welded, nodal joints in braced structures composed of hollow sections of circular or square shape (with or without rectangular chord) under fatigue loading. This International Standard applies to structures: fulfilling quality requirements for hollow sections (see AnnexA); complying with recommended weld details (see AnnexB); employing permitted steel grades (see 1.2); having hollow section joints (see 1.3); having either square or rectangular hollow sections with a thickness between 4mm and 16mm, or circular hollow sections with a thickness between 4mm and 50mm; having as stress range the range of “hot-spot” stress; having identical brace (branch) members. 1.2 Materials This International Standard applies to both hot-finished and cold-formed steel structural hollow sections, complying with the applicable national manufacturing specification, that fulfil specified quality requirements (see AnnexA). 1.3Types of joints This International Standard applies to joints consisting of circular hollow sections (CHS) or rectangular hollow sections (RHS) as used in uniplanar or multiplanar trusses or girders, such as T-, Y-, X-, K-, XX-, and KK-joints (see Figure1 and Figure2).