[jim_trent]

I am a FHWA certified bridge inspector, with additional certification for Fracture Critical Steel Bridges, and have inspected bridges in the past, so I am getting a kick out of these posts.

I have posted about that in the past and have been criticized in this forum for “sucking on the government teat”, even though I actually work for a private engineering company doing inspections for government entities. Many here were critical of the Federal requirement to inspect bridges regularly. One person here went so far as to state that there should be a sign posted at the entrance to each bridge saying “Cross at your own risk”. I wonder what he is saying today.

It looks from the photos that it was a fracture critical steel bridge. That means there is no redundancy. If any one of a number of parts breaks, the whole thing comes down. Newer bridges (and this is a newer one, being only 30 or so years old) are usually built without redundancy. Why? Because it is cheaper. No one wants the government to spend more than absolutely necessary.

Bridges such as this one are supposed to be inspected once a year (non-fracture critical are inspected every two years). There is a report that this one was listed as “structurally deficient” in the past. This does not mean that the whole bridge had to be replaced immediately. Probably, the whole bridge was not deficient. Some things are relatively minor in cost, but can cause collapse if ignored. If this was the case here, it should have been repaired by now. Sometimes repairs are not done. Sometimes they are not done correctly. Sometimes other deficiencies are missed.

I will be very interested in what the investigation comes up with because as of right now, nobody knows anything.

[brothers4thID]

There was a big report released by one of the agencies in 2002 about infrastructure vulnerabilities. What I recall most was a bridge inspector saying that it wasn’t terrorists we should be concerned about, it was normal wear and tear and government ineptitude. Basically, we were/are running around terrified of radicals putting some c4 on a truss when mother nature and father time were/are ten times more likely to cause havoc.

[listenhillary]

Did you check out the youtube video?

http://www.freerepublic.com/focus/f-news/1874950/posts?page=1760#1760

Interested in hearing your analysis.

[KC Burke]

I will be very interested in what the investigation comes up with because as of right now, nobody knows anything.

I agree, being in construction, these forensic issues are very interesting but take time to really be understood.

As for right now, I am going to list the cause as "Excesses During the Clinton Years." until I have something better.

[Dead Corpse]

Spokesmouth this AM on local news said it was inspected last year and was found to be ok.

It'd be interesting to get our hands on a copy of that inspection and have you go over it...

[KC Burke]

An interesting web page about this bridge can be found Here on John Weeks' web pages. He has photographed almost every Mississippi bridge as a hobby.

Structure photos of the bridge pre-collapse are on this page as well.

[KC Burke]

I was under the impression that newer bridges were built with enough redundancy for single failure survival and that it was some of the mid and early twentieth century structures that were not? I am I being too hopeful?

[FReepaholic]

Finally a calm, rational post.

Did you see this video of the collapse?

Security Camera Footage of the Collapse