FATIGUE-STRENGTH OF WEATHERED ROLLED BEAM MADE OF A588 STEEL

This study investigates the fatigue behavior of corroded rolled beams made of A588 steel. The beams were weathered under two conditions: One set was boldly exposed to the environment; the other was exposed under a metal deck that simulated the shelter provided by highway bridge decks and lightly sprayed with a salt solution during the winter months. Bold exposure for 62 months and stress cycling in a moist freshwater environment decreased the fatigue strength from category A to B. Sheltered exposure for 67 months and stress cycling in a moist saltwater environment decreased the fatigue strength from category A to E. The one-category reduction in fatigue strength, from A to B, adopted in the latest specifications from the American Association of State Highway and Transportation Officials may be adequate for ideally and boldly exposed weathering-steel base metal, but it does not represent the loss in fatigue strength that can be expected of weathering-steel base metal exposed to the variety of conditions typically found in service.