At face value, the corrosion makes no sense whatsoever. This is central California, there is no way an un-grouted steel cable can develop such a serious corr

At face value, the corrosion makes no sense whatsoever. This is central California, there is no way an un-grouted steel cable can develop such a serious corrosion issue and in such a short time. If it was some place with acid rains, exposed to the sea, etc, that would take tens of years, AND it would have needed traffic on the bridge, possibly above the theoretical allowance. Disclaimer: I have been site manager in the construction of several pre- and post- tensioned reinforced concrete bridges, I have dealt with this stuff for years, but of course I know nothing of the specific project and/or exact type of cables used in it.