Tests of X- and K-joints in SHS stainless steel tubes

This paper describes a test program on welded stainless steel X- and K-join ts fabricated from square hollow section (SHS) brace members and chords. Th e X-joints were tested in compression and tension using different ratios of brace width to chord width. The K-joints were tested by varying the ratio of brace width to chord width, the angle between chord and brace members, a nd the preload applied to the chord. A total of 23 tests were performed. De sign rules are proposed for X- and K-joints by adopting the rules of the Co mite International pour le Developpement et l'Etude de la Construction Tubu laire (CIDECT) recommendations for carbon steel tubular structures and repl acing the yield stress in these recommendations by a proof stress. It is sh own that the 0.2% proof stress, as determined from the finished tube, can b e used to determine the ultimate strength using the CIDECT design rules and that the serviceability limit state corresponding to joint deformations of 1% of the chord width will not be reached if the CIDECT strength rules are adopted. It is also shown that the CIDECT strength rules produce unconserv ative design strengths when using the 0.5% proof stress in cases of high co mpressive forces in the chord. However, the serviceability limit state will generally not be reached if the 0.5% proof stress is used.