Effect of Thickness and Joint Type on Fatigue Performance of Welded Thin-Walled Tube-Tube T-Joints

This paper summarizes the proposed fatigue design curves for three different thin-walled T-joints following the testing of 99 specimens in the as welded condition. The specimens are made up of cold-formed high-strength thin-walled (t<4mm) circular hollow sections (CHS) and square hollow sections (SHS). Fatigue tests were carried out under constant amplitude stress range on thin CHS-CHS, CHS-SHS and SHS-SHS T-joints, for the load "in-plane bending in the brace". Fatigue failure occurred in chord members of thicknesses 3mm, 3mm and 3.2mm for SHS-SHS, CHS-SHS and CHS-CHS T-joints respectively. Different options are recommended for the design of the T-joints based on the deterministic method and least-squares method of statistical analysis.