Fatigue of Two Year Weathered A588 Stiffeners and Attachments

An experimental program examined the effect of A588 steel specimens with transverse stiffeners and attachments. It was found that two years of continuous weathering, prior to stress cycling to failure, reduced the fatigue life of the specimens with stiffeners and attachments by 19 and 6 percent, respectively, as compared to the non-weathered control specimens. Two years of alternating between 6-month weathering and one-quarter-life stress cycling had no significant effect on the fatigue life. The present data, in conjunction with earlier results, suggest a larger weathering-induced loss in fatigue life the more fatigue strength the specimen had in a non-weathered state. Since weathering prior to cycling affects only the crack initiation phase, whereas unpainted A588 bridges are continuously exposed to the environment, it is prudent to regard the fatigue strength of the weathered specimens as an upper bound on the fatigue strength such details would exhibit on actual structures.