Oregon Bridge Uses Stainless

摘要

The state of Oregon in the northwestern United States is using S32205 stainless steel as an antidote to the corrosion problems that plague some of its older bridges along the Pacific coastline. A 12-million US dollars bridge now under construction over an estuary near Coos Bay will contain 363 tonnes of stainless steel rebar, believed to be the largest quantity of stainless steel used for any bridge in North America. The Oregon marine environment is hard on bridges reinforced by carbon steel rebar. Wind blows salty, moist air under the deck and T-beams, where it condenses and causes corrosion. The resulting cracking along the contact between the rebar and the concrete is exacerbated by tensile cracking caused by heavy traffic loads. Eventually, rust forms and the concrete begins to crumble, weakening further the bond between the metal and the concrete. Structural failure has been known to occur in as little as 17 years.