950 ton pedestrian bridge collapses

[Allen]

Rifles with detachable magazines and folding stocks now to be banned.

http://www.dailymail.co.uk/ushome/index.html

[togor]

Classy remark from a classy guy.

[leftyo]

obviously building a bridge in six hours is problematic. so we obviously need to ban bridges or sucky engineers.

[blackhawknj]

Students will be walking out to protest.

[JB White]

Let's hope they don't do a count as to the race of the victims. Should more blacks be killed than anyone else, they'll not only walk out but they might also burn bridges.

Sad thing. I can't understand why they would do stress testing over moving traffic.

[Mark in Ottawa]

My understanding is that the bridge was supposed to be equipped with a tower from which would drop a number of heavy cables that would provide support for the bridge deck. I heard on the news that for some unknown reason the tower and the cable were not to be constructed until next year. That makes no sense to me given that as soon as the bridge opened it would have to b e capable of carrying its full design load and would presumably need that extra support immediately. If for some reason that year delay really was the intent then it has to be presumed that at some future date the bridge would be expecting to carry some additional load that would need the cables. In that case the bridge had to be fully self supporting now. I did hear that the contractor was in the process of tightening cables so I presume that the design called for post-tensioning of the concrete slab. Post tensioning allows for thinner concrete slabs and is supposed to minimize cracking. The problem is that until the post tensioning is complete, the slab is not up to full strength . I suspect that that may be the problem in this case. That would suggest that the roadway should have been temporarily closed or there should have been temporary support provided to the structure. Of course there could be other problems such as concrete that is weaker than the design called for or even a totally poor structural design.

[Mark in Ottawa]

Second Posting: Here are some photos of the type of bridge that collapsed showing the cables. These are from the website of the company that designed this one (FIGG Engineering): http://www.figgbridge.com/cable_stayed_bridges.html

[Allen]

There's a lot of ???? and red flags going up over this. AFTER the collapse the engineer said he saw cracks and tried to "warn" everyone. Sounds to me he is trying to duck out of responsibility and lawsuits. Just read today where 3 more bodies were pulled out of the vehicles that were smashed. They said the bodies can only be identified by DNA.