Aware of that one. The trail bridge at Pilarcitos Creek on the California Coastal Trail in Half Moon Bay was made of unpainted Cor-Ten steel. That will not last in the coastal zone, where it never dries out. The bridge collapsed when park staff drove a tractor across it.[1] No injuries, but the heavily used trail was out for most of two years.

The new bridge is made of marine-grade aluminum.

[1] http://www.hmbreview.com/news/groundbreaking-for-coastal-tra...