Design of Single-Sided Fillet Welds Under Transverse Loading

Abstract

In North American steel design codes, a “directional strength enhancement” (or “sinθ”) factor is used to increase the predicted strength of fillet welds subjected to tension-induced shear. CSA and AISC code committees have expressed concerns about this factor being potentially unsafe for single-sided fillet welds; however, only cautionary, but vague, statements to address this issue exist in codes. An experimental program was therefore developed at Dalhousie University to test 40 single-sided fillet welds in cruciform connections subjected to branch axial tension. Using ultimate loads, a first-order reliability analysis was performed to determine the inherent safety index (β) of North American fillet weld design procedures. The results show that current provisions meet/exceed the target safety index (i.e. β = 4.0) specified by North American codes (e.g. CSA S16 and AISC 360) provided that: (i) the “sinθ” factor is not used and (ii) tension at the weld root is avoided.