Corten steel is often used structurally, even in recent structures, because the idea is that the rust forms a protective layer. As long as water is not allowed

Corten steel is often used structurally, even in recent structures, because the idea is that the rust forms a protective layer. As long as water is not allowed to pool, it shouldn't rust through. Some pictures of Corten steel structures: https://www.corten.com/what-is-corten-steel.html https://www.corten.com/what-is-corten-steel.html I'm familiar with the structures shown in that link. The U.S. Steel Tower seemed to be holding up well when I worked there, although looking out some windows you could see slightly worrying depressions in the steel beams where water had pooled over the years, and the steel had rusted away a bit (leading to more pooling). The Delaware footbridge was constructed much more recently and still looks new - no signs of wear that I've noticed walking across it. If Corten steel is not durable enough for structural use, we're in trouble. It's used quite a bit, at least in the northeast.