Fatigue and residual strength of concrete-filled tubular X-joints with full capacity welds

• DOI: 10.1016/j.jcsr.2014.04.021
• Publication Date: 2014-05-03T23:45:39Z
• Authors: Xudong Qian; Kittikun Jitpairod; Peter Marshall; Somsak Swaddiwudh...; Zhiyong Ou; Yang Zhang; Mochamad Raditya ...
• Keywords: Concrete-filled sections; Fatigue crack initiation; Full capacity welds; Fatigue crack propagation; S-N curve; 02 engineering and technology; Tubular joint; 551; 0201 civil engineering

Abstract This paper presents the experimental findings on the fatigue performance and residual strength of the circular hollow section X-joints with a concrete-filled chord. The welding profile along the brace-to-chord intersection employs a recently proposed set of welding details, namely the full capacity tubular joint welds. The experimental investigation focuses on: 1) the stress concentration comparison corresponding to different stages of the specimen preparation, 2) the fatigue crack initiation life and propagation life; and 3) the comparison of the measured fatigue life with respect to the design S-N curves. The experimental measurement reveals that the fatigue crack propagation life contributes to a significant portion of the total fatigue life for both the hollow section tubular joints and the concrete-filled tubular joints. The total fatigue life of the test specimens complies with the life estimation based on the existing design S-N curves, originally developed for tubular joints fabricated using the complete joint penetration welds. The residual strength of the fatigue-cracked tubular joints follows approximately a linear relationship with respect to the percentage of the crack area along the brace-to-chord intersection.