Four years ago today the Minneapolis 35W bridge collapsed.

http://kstp.com/article/stories/S2223310.shtml?cat=1

A typo during the original construction resulted in the gusset plates which connected all girders being half an inch thick rather than one and a half inch thick.  Before, during and after the construction no one caught the error.

Just after the collapse a news story casually mentioned that the steel gusset plates had worn down to three-quarters of an inch.  I was thinking that stationary steel plates do not "wear down".   Rust and paint may make them thicker.

Had someone with the engineering knowledge started from scratch and looked at the bridge design they might have said "What the f____" when they saw the half inch gusset plates.  If this was discovered structural reinforcement would have been easy.  Thbe only other US example of this I can think of the is the New York City Citi-Corp headquarters.  (It has the distinct "Lean To" roof..  An architectural student studied the building and concluded that it could collapse in a hurricane force wind.  After rechecking the calculations the student presented the finding to the architect.  The architect, concluded the students calculations and conclusions were correct.
The architect first contemplated suicide but then took on a fix which was done at night and weekends  in secret to not panic neighbors and employees.   Basically it meant  bolting and welding gusset plates to the existing girders.  It worked and now the CitiCorp NY building is one of the strongest in NYC. Had someone discovered the same flaw in the Minneapolis 35W bridge a Citicorp type fix would be possible.

Thirteen people died in  the collapse.  Fine decent people who really were "victims".  I used the bridge frequent so I figure my probabily was around one million to one to be on the bridge during the collapse.