Fatigue Behavior of Blast-treated Out-of-plane Gusset Fillet Welded Joints

Blast cleaning prior to coating has been applied in newly built steel structures for cleaning forged surface and increasing adhesive property of applied coating systems. However, the effect of surface preparations by blast cleaning treatment on fatigue behavior of welded joints is not considered in Fatigue Design Codes. In this paper, fatigue tests were carried out on four types of out-of-plane gusset fillet welded joints, as-welded gusset specimens and three types of blast-treated gusset specimens, and then the effect of the blast cleaning treatment on the fatigue behavior of the welded joints was studied. The radius of curvature at weld toe of the blast-treated specimens was larger than that of as-welded specimens. The fatigue test results showed that the fatigue life of the blast-treated specimens is longer than that of as-welded specimens in low stress ranges, even though there is no significant difference in fatigue life between the two types in high stress ranges. Over 167% increase in fatigue limit could be realized by using blast cleaning treatment.