Fatigue performance of tubular X-joints with PJP+ welds: I — Experimental study

This study examines the fatigue performance of tubular joints fabricated using a new type of enhanced partial joint penetration weld details under constant-amplitude brace in-plane bending actions. The experimental program includes four cyclic tests on two large-scale X-joints, each with a different surface treatment near the weld toe. The experimental results confirm the satisfactory fatigue performance of the tubular X-joints welded using enhanced partial joint penetration welds in comparison with the S-N curves developed for tubular joints with complete joint penetration welds, and demonstrate the significant improvement on the fatigue life rendered by the weld surface grinding and toe grinding. Root fatigue cracking occurs only in specimens with post-weld toe-grinding treatment which enhances the fatigue life for toe cracking.