ABSTRACT
Fatigue tests were carried out on welded thin cold-formed T-joints made up of circular hollow section (CHS) chords and braces under cyclic in-plane bending. The experimentally determined stress concentration factors (SCFs) from these joints are found to be smaller than the SCFs from existing parametric equations. This is due to the fact that oversized welds which are a characteristic of thin-walled (t < 4 mm) joints move the hot spot locations away from the regions of higher stress. The ratios of end of test fatigue life (N4) to through thickness fatigue life (N3), determined during the fatigue tests, are found to be comparable to ratios from previous research on both thin and thicker walled joints. The resultant fatigue test S-N data from the thin-walled joints is compared to the design S-N curves from current fatigue design guidelines as well as to S-N data from welded thin-walled tubular T-joints made up of square hollow section (SHS) chords and braces.
