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2007-08-01 -Short Attention Span Theater-

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Posted by Mike 2007-08-01 20:20|| || Front Page|| [11140 views ] Top

#1 On Fox, the Minneapolis TV news is reporting that the bridge was being resurfaced, and there was some sort of explosion where the construction equipment was.

Posted by Mike 2007-08-01 20:31|| 2007-08-01 20:31|| Front Page Top

#2 What better cover to blow up a bridge than a bunch of construction work...

Posted by Evil Elvis 2007-08-01 20:35|| 2007-08-01 20:35|| Front Page Top

#3 Any taxis nearby?

Posted by Nimble Spemble 2007-08-01 20:44|| 2007-08-01 20:44|| Front Page Top

#4 Strange. Modern bridges have stress indicators built into their structures, and most local administrations issue standing orders re. daily supervisory checks. I smell negligence at some level.

Posted by McZoid 2007-08-01 20:45|| 2007-08-01 20:45|| Front Page Top

#5 Let me put it this way: If there weren't any Muslims in Minneapolis just about nobody would be worried about this being an incident of terrorism. Just sayin'.

Posted by Zenster">Zenster 2007-08-01 21:04|| 2007-08-01 21:04|| Front Page Top

#6 Modern bridges have stress indicators built into their structures, and most local administrations issue standing orders re. daily supervisory checks

that's nonsense, McZ. I've been Resident Engineer on construction of 17 bridges, concrete and steel. Yearly condition checks are the norm in California (Caltrans). Looks like progressive collapse/failure - it's 40 yrs old and should have at least a 50 year life cycle. The witnesses' statements of shaking and vibration noise changes sounds like material or design issue. Perhaps the construction work damaged it or environmental (ice/snow/salt) impact on the steel reinforcement. Stress indicators are only on relatively new structures (last 10-15 years) or recent retrofits on old "problem" bridges. Inspections over water and canyons involve articulated snooper "cherry-picker" boom trucks and are expensive, intensive. Caltrans has, I think, 2 "snooper" trucks for all of Southern California

Posted by Frank G">Frank G 2007-08-01 21:08|| 2007-08-01 21:08|| Front Page Top

#7 Train is crush under it ...
look at the video
cars and trucks in the river and crushed everywhere.
Hospitals are selectively calling up lots of doctors.

Posted by 3dc 2007-08-01 21:11|| 2007-08-01 21:11|| Front Page Top

#8 Most of the bridge segments appear intact. I would expect to see crater type damage if there had been an explosion. From the shots on TV, the collapse twisted a segment on the Minneapolis side while all the other segments seem to have remained relatively flat.

In St. Pete, a ship struck a bridge pier. A couple of others were just structural failures. It remains to be seen what happened here. Fox is reporting the bridge was inspected in 2004??

Posted by Chuck Simmins">Chuck Simmins 2007-08-01 21:15|| http://northshorejournal.org]">[http://northshorejournal.org] 2007-08-01 21:15|| Front Page Top

#9 Perhaps the construction work damaged it or environmental (ice/snow/salt) impact on the steel reinforcement.

I gotta agree with you, Frank G. Between thermal cycling, induced corrosion and the age factor the chances were high that some serious structural degradation had occurred. As a major tranportation artery, the bridge should have had cameras continuously monitoring it for traffic congestion, if not the construction itself. Image analysis of those recordings would go a long way towards providing an explanation.

Also, crater or not, one single point failureinduced or accidentalwould not seem likely to cause such a near total structural break down. There must have been a multitude of weak points whose failure cascade avalanched into such a spectacularly comprehensive collapse.

Posted by Zenster">Zenster 2007-08-01 21:27|| 2007-08-01 21:27|| Front Page Top

#10 I'm surprised Zawahiri hasn't claimed it as a great al Qaeda victory, whether it failed due to material, design or sabotage. I wonder if there were any of those picky Muslim cab drivers caught up in the collapse?

Posted by Glenmore">Glenmore 2007-08-01 21:34|| 2007-08-01 21:34|| Front Page Top

#11 Fox: "stress fractures noticed a year ago....the construction was apparently only surfacing.... Last inspected in 2004"

I doubt they could/would cut post-tensioning cables or enough cables to cause the collapse. The deck structure looks thin, like girder/PT deck construction, not box-girder, although there is some twisted/ruined steel substructure visible at one end

Posted by Frank G">Frank G 2007-08-01 21:46|| 2007-08-01 21:46|| Front Page Top

#12 before photos

Posted by 3dc 2007-08-01 22:40|| 2007-08-01 22:40|| Front Page Top

#13 Frank is probably dead on. Environmental factors most likely stacked up to cause this. Thermal cycles? Check. Salt? Check check check check check. That liquid crap they use now instead of salt, you know, that shiat that will corrode stainless pronto? Checkmate I'm guessing.

I don't know what that crap is that they use now, but its nasty stuff. Even seen what dissimilar metals will do to each other when they come in contact with each after several years? like aluminum and a plain old bolt? That new crap will do that in a single winter. I think its magnesium something or other. I've personally seen it corrode a whole in stainless truck bumpers. It looks to me like it gets between a mount and the bumper and never gets cleaned off. I've also seen it rust brake shoes so bad that it cracks the lining in a single winter also.

Posted by Mike N. 2007-08-01 22:48|| 2007-08-01 22:48|| Front Page Top

#14 wcco slide show

Posted by 3dc 2007-08-01 22:48|| 2007-08-01 22:48|| Front Page Top

#15 thanks - passed them on to my work email for later distribution to colleagues

Posted by Frank G">Frank G 2007-08-01 22:51|| 2007-08-01 22:51|| Front Page Top

#16 Mike N. --

magnesium sulfate or magnesium cloride solution, I think. It's death on aluminum.

Posted by N Guard 2007-08-01 22:55|| 2007-08-01 22:55|| Front Page Top

#17 That sounds about right. Chloride. From my crude understanding of chemistry, the ide part is what's causing the trouble.

If any of it gets on a piece of polished aluminum treadplate or something, it has to be washed off immediately. If you wait an hour, you're too late.

Posted by Mike N. 2007-08-01 23:01|| 2007-08-01 23:01|| Front Page Top

#18 Fox now reporting traffic was stopped in full bumper to bumper traffic jam at the time of the collapse

Posted by 3dc 2007-08-01 23:04|| 2007-08-01 23:04|| Front Page Top

#19 Seems there were only 2 lanes open, one north and one south. Could have been twice as many cars.

Posted by Sherry">Sherry 2007-08-01 23:12|| 2007-08-01 23:12|| Front Page Top

#20 Seems there were only 2 lanes open, one north and one south. Could have been twice as many cars.

Well, it's a 6-lane highway through there, plus a 4th lane on each side for on/off ramps to local roads ... so, it could have been even more than twice. I thought the "down to a single lane" was just in one direction though.

Posted by ExtremeModerate 2007-08-01 23:19|| 2007-08-01 23:19|| Front Page Top

#21 That bridge is bumper to bumper every single day, twice a day.

Posted by Mike N. 2007-08-01 23:19|| 2007-08-01 23:19|| Front Page Top

#22 There were two lanes open in each direction.

Posted by Mike N. 2007-08-01 23:32|| 2007-08-01 23:32|| Front Page Top

#23 My heart goes out to the people of Minneapolis. Lives were lost and so was a fairly beautiful bridge. It makes me proud to see professional EMS, fire and police crews on site and doing their best without worrying overmuch about their own well-being.

Posted by Zenster">Zenster 2007-08-01 23:56|| 2007-08-01 23:56|| Front Page Top

23:56 Zenster
23:32 Mike N.
23:23 borgboy2001
23:20 James
23:19 Mike N.
23:19 ExtremeModerate
23:16 borgboy2001
23:12 Sherry
23:04 3dc
23:01 Mike N.
22:59 James
22:59 SteveS
22:55 N Guard
22:54 crosspatch
22:54 Rich G.
22:51 Frank G
22:48 3dc
22:48 Mike N.
22:47 tu3031
22:40 3dc
22:27 Steven
22:25 Mike N.
22:25 Jonathan
22:23 Zenster