pglaves
#13338
I figured you got enough freezing weather that the DOT would salt the bridges.
Maybe it does not happen enough to be a issue.
You're right about exposed steel being left bare on some structures now.
Back in the '70s and '80s there was a lot of use of "Corten" (sp?) steel. It was polished and then left to oxidize (rust) naturally. It would turn reddish orange but not get crusty. It was used as a "design feature" and was a bit of a fad. Minnesota used it for support columns and beams at some new Interstate rest areas.
https://en.wikipedia.org/wiki/Weathering_steel