I recently got an excellent email from a friend in Minnesota. He had some useful comments and good pictures regarding the I-35 W bridge collapse in Minneapolis. With his permission, I am including his text below. (If you interested, I have offered my own comments here before.)

With the 13 or so bodies and the many vehicles recovered, with demolition under way, and with the kiddies coming back to the U, they finally re-opened the 10th/19th Avenue Bridge (which connects parts of the campustown areas) on Friday the 31st, and I went there today (the one-month anniversary of this tragedy) to see what there was still to see - which was plenty. I took about 100 photos, most of which look about alike. I narrowed it down to these, and again shrank them for Internet on-screen.

They have about a 7-foot fence on the overlook bridge, and trying to take pictures through it doesn't work that well, so I had to resort to reaching up over the fence. Height comes in handy at times. :) When you're taking pictures you don't always have time to observe what's going on in fine detail, and then you see it later. In this case, they were filling one barge with stuff they were dredging up, and another barge came through the lock of the "Lower St. Anthony Spillway", and finally both of them took off, maybe for lunch somewhere downriver. Notice that the lock-and-dam were not directly under the bridge. Somehow I have a hunch that is not a coincidence.

Upstream is roughly west-northwest, so the pictures are generally with south or southwest on the left, and north or northeast on the right. Looking upstream you can see the Stone Arch Bridge, which was built in the 19th Century, and you can just barely see St. Anthony Falls between its arches. Past that you can see the 3rd/Central Avenue bridge. In a couple of photos you can see the 10th/19th Avenue bridge, which had lots of people walking and picture-taking, and lots of slow-moving traffic. They have barricaded a pedestrian area to allow people to walk and gawk on the bridge without worrying about the cars.

There seems to be debate about where the trouble began, on the north or the south portion of the span. As you can see, the south end was more twisted and torn than the north half. The security camera video (Note: My friend is referring to the video I linked in my article.) seems to show the visible part of the collapse occurring in almost the middle of the steel arch of the bridge, but it's hard for a layman to judge from that video where the break originated. It's clear that the south side is in relatively worse shape than the north side, i.e. the north side of it broke more "cleanly". Note that all the other bridges along here have multiple arches (except for Hennepin Avenue, which is a suspension bridge, out of range in one of the photos unless you know exactly where to look). The single-arch aspect of the I-35W bridge may have been its undoing, some way or another. However, there is also concern about a design flaw in the way the girders were connected together.

It will be interesting to see what the experts come up with. Current estimates are that they might have the replacement built before they finish the investigation of the previous one. Somehow that is not a warm-fuzzy thought.

After I wrote to my friend asking if I could put his comments on this site, he replied as follows:

Just say "a friend from Minnesota"; no names, please. :)

That's what happens in the news, typically. There's a big flurry of media activity (Shepherd Smith and Greta Van Susteren of FoxNews were here!), the politicians show up and wring their hands (Bush, Coleman and Klobuchar were here!), and then it's off to the next disaster, leaving the "little people" to do the actual work. And there is plenty left to be done. Once they got the bodies and cars out of the way (and feel free to edit my writing to be a little less blunt), the next step apparently was to clear the shipping lane for the barges that use the lock-and-dam system, and then to start removing the concrete from the collapsed roadway. I expect they want the steel saved in order to try to figure out what went wrong. Then they have to get crackin' on building a replacement. They're hoping to have it done by the end of 2008. I would like for them to take their time and do it right, rather than being deadline-driven.

---