I still haven't hard from Chris (Schulace123).
As for bridge use, I drive it ALL the time. Nicky (UnderwaterGirl) lives just on the other side of it from work - about six blocks. John (one of my interns) lives about 4 blocks on the other side of it. It is the main North/South entry into downtown Minneapolis.
New theory is that the construction crew srcewed up. They had too many supports out to replace, and too much weight from heavy equipment on it at the time. If you look at the main break point, you'll see it was right where they are working and a massive amount of heavy machinery sitting in a pile.