http://www.visi.com/~jweeks/bridges/pages/ms16.html
Posted on 08/01/2007 4:28:27 PM PDT by ButThreeLeftsDo
Just turned on the news. 35W bridge collapsed in the Mississippi River. Cars, trucks, semis.....
Fires burning, tanker trucks, at least one school bus, more than ten cars......
Just now breaking.......
The “block” lost internal integrity. It deformed diagonally, towards the downstream direction.
You lost a diagonal brace in there somehow, could have been overload, could have been a shoe collapsed, some crumbling of the piers (though they appear to be intact in the imagery) bolts connecting diagonals to uprights, etc.
Look at the picture in post #1404.
From the top of the nearest pier, follow steel vertical a short distance till you reach a diagonal that runs towards the top of the steel truss on the other near side pier. It’s purpose is to keep the trusses vertical over the piers and parallel to each other, so the deck can’t sway sideways, away from bearing directly over the piers.
From the available imagery, this appears to be where and how the failure occured.
Deliberate act has to remain a possibility, but my best guess says construction accident. On many jobsites, you have licensed and highly experienced engineers designing the final result, and much lesser mathematically inclined supervising the design of falsework and order of re-construction. Even if this level of management gets it all perfect, you still have the stiffs who may or may not carry out orders perfectly every time.
Gravity is a cruel mistress who tolerates very little error.
Very creepy Mike. I’m never going to get to the end of this thread. I keep trying and afraid I’ll miss something important. On threads like this I’m always nearly 600 posts behind.
9/11 is the worst collapse and one of the worst disaster in American history.
I realize they still aren’t sure of fatalities, etc. But after seeing these pics, I am amazed there are not more fatalities and injuries at this point.
Still more details to come though, sadly.
Why do you think that bridge in Lake Charles will go?
I drive over a bridge daily over a little creek, Jones Creek, and the levels of the water rise dramatically with rain, all the way to the roadway. It scares me,,I just don’t think that bridge can withstand that kind of water coming up so much. Usually the water line is a good 20 feet below the road.
But what is it about that bridge? I drive over it from time to time.
When all is said and done, it will be this....
Bumper to bumper traffic due to construction maximized the amount of traffic vehicles (weight) on the bridge.
Construction crews and their personal vehicles added more weight.
They were poring concrete and had numerous large concrete trucks (overly heavy loads concentrated in small areas).
They had many smaller liquid concrete vehicles moving and pouring concrete (bobcat size).
During this period, a train was passing by underneath, which caused a flexing (depression) of the ground support for the bridge, causing the girders to drop and flex.
This bridge has no center piers buried in the river bed like many others. It was supported only by the ends, and they couldn’t take all those forces at once.
All the high paid engineers in the world can come together and mindstorm this, and I’ll bet my last dollar ($4.00 actually) that this is the conclusion, if they tell the truth.
Someone missed out on pre-analysis of all the possible factors when they decided to allow heavier than normal concrete pouring vehicles to be on that bridge during bumper to bumper rush hour. They should have poured at night.
So, it depends on whose behind could get burnt, as to the ‘truth’ being told.
Look for a scapegoat to be picked, soon.
Joining you in prayer for all! What a Nightmare!
You’re creeping me out!! {shudders}
But wasn't the bridge widened? That might have resulted in a deep reduction in safety factor (to 0.9?).
Right after MN. DOT has contacted their lawyers.
I heard him, too... I AM concerned about bridges just falling in the water - if it is NOT terrorism (and the fact that the Dept of Homeland Security so quickly said it wasn’t is a little suspect to me — but then again they always do that).
How can they not say it is not terrorism? Did anyone else notice how Mark Furhman was cut off on Hannity and Colmes tonight when he ventured in that direction?
That’s precisely the point I was trying to make. Plus, the uprights/verticals atop the concrete piers not only bear the compressive load that any single internal truss-member would; they bear it for TWO truss sections which share that particular (upright) chord; AND they bear the weight/mass of a bunch of sections. Now, the verticals appear to be composed of 2 channels joined together box-style like so [ ] with intermittent cross pieces, whereas the internal truss members appears to be a straight “I” beam. So they are stronger but not massively stronger.
Add some normal rust, which seems evident from the pix...the unequal load from the one-side-only traffic condition, maybe some fastener deterioration from freeze-thaw back/forth movement.....and you have a news story.
Red Cross calling out for blood donors.
I’m in Chicago, but I’ll head out to LifeSource in the morning to donate.
The bridge next to it has two piers in the water. That is where they are getting confused. I have looked at it on VirtualEarth and the KTSP live feed.
Haste makes waste (and fools).
When we moved here I was struck by the fact that people would stop at the entrance to the Shadle Bridge if there was a lot of traffic on it, and nobody would blow their horn at them. Everyone was afraid to get on it if there was traffic. I was stuck on it a few times and it was not fun. The whole thing would shake rattle and roll. I’m scared of bridges anyway. Thank God for the new bridge. I watched the Shadle being blown to bits and cheered.
The details will take months or even years, but eventually, it will agree with what was figured out within the first day or two.
In that case, a structual failure due to metal fatigue and corrosion caused by the harsh Minnesota weather.
Failure of DOT inspectors to identify the structual problems which caused this specific failure.
Lack of State and Federal funding, to correct the problems which were already identified.
Eyewitnesses say it fell somewhat slowly. That probably mitigated injuries.
Thanks Jeffers.
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