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Pre-collapse photos show bends on bridge ( Minnesota )
The Associated Press...Star Tribune ^ | Mar 23, 2008

Posted on 03/23/2008 7:36:56 PM PDT by george76

Old photos of the Interstate 35W bridge show two steel connecting plates were visibly bent as early as 2003 — four years before the span collapsed into the Mississippi River, killing 13 people.

Minnesota Department of Transportation officials declined to say when the state first knew about the bending in the pieces of steel, called gusset plates.

Two photos, part of a report issued earlier this month by the National Transportation Safety Board, reveal slight bends in gusset plates that hold beams together at two separate connecting points. The plates are in areas believed to be among the first points of failure when the span collapsed.

The NTSB's Office of Highway Safety confirmed that the bowing is part of the investigation into why the bridge collapsed Aug. 1, NTSB Chairman Mark Rosenker didn't comment on the photos, but has said the original design for the bridge specified steel for those and other gusset plates that was too thin.

NTSB spokesman Terry Williams told the Star Tribune the bowing is among "the many things that we are looking at as part of this investigation."

The newspaper said inspection records make no mention of repairs to the bending gusset plates.

Since the bridge's construction during the 1960s, the state highway department had increased weight on the bridge by adding a layer of concrete to the deck in 1977 and by installing concrete barriers in 1998. And the NTSB said last week that, at the time of the collapse, more than 191 tons of construction material had been piled over the bridge's weakest areas.

(Excerpt) Read more at news.yahoo.com ...


TOPICS: Crime/Corruption; Extended News; Government; US: Minnesota
KEYWORDS: 35w; bridge; bridgecollapse; collapse; minneapolis; ntsb
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1 posted on 03/23/2008 7:36:58 PM PDT by george76
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Bent gusset plates on the Interstate 35 W bridge are seen ( center) in this 2003 photo released by the National Transportation Safety Board.old photos of the Interstate 35W bridge show two gusset plates were visibly bent as early as 2003 — four years before the span collapsed into the Mississippi River, killing 13 people.

Photos released this month by the National Transportation Safety Board show the plates that hold beams together at two separate connecting points are slightly bent.

.


2 posted on 03/23/2008 7:40:01 PM PDT by george76 (Ward Churchill : Fake Indian, Fake Scholarship, and Fake Art)
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To: george76

Whole lotta stupidity going on in this Socialist Paradise.


3 posted on 03/23/2008 7:41:42 PM PDT by Post Toasties (It's not a smear if it's true.)
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To: george76; Admin Moderator

Mods, if you can't link to an AP photo here, please pull my post.

4 posted on 03/23/2008 7:42:30 PM PDT by coloradan (The US is becoming a banana republic, except without the bananas - or the republic.)
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To: george76

Are not government “bridge inspectors” responsible for disclosing this?


5 posted on 03/23/2008 7:42:33 PM PDT by Mad_Tom_Rackham ("The land of the Free...Because of the Brave")
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To: george76

One article even noted that there was 191 tons of construction material piled on the weakest point of the bridge at the time of the collapse.


6 posted on 03/23/2008 7:42:44 PM PDT by Incorrigible (If I lead, follow me; If I pause, push me; If I retreat, kill me.)
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To: george76

what am I missing?


7 posted on 03/23/2008 7:43:06 PM PDT by the invisib1e hand (Free New York)
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To: george76

If that was 2003 and there were slightly bent then....then how the hell did they inpsectors miss them later?

In theory they should of been bent more by then...and much more then what is shown here if that was indeed the cause


8 posted on 03/23/2008 7:47:47 PM PDT by janetjanet998
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To: the invisib1e hand

The bends are not severe, but they indicate that there were forces on the plates that weren’t kosher.


9 posted on 03/23/2008 7:48:21 PM PDT by 1rudeboy
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To: Post Toasties

You said it. They can spend a fortune on the welfare state but can’t fund infrastructure— the one government function.


10 posted on 03/23/2008 7:49:39 PM PDT by A_Former_Democrat
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To: the invisib1e hand

In both photos

Take a look at the large vertical plates with all the rivets in them.

Then look at the forward edge of each...it should be perfectly straight, but it is slightly wavy


11 posted on 03/23/2008 7:49:42 PM PDT by kidd
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To: 1rudeboy; kidd
glad I don't feel called to be a bridge inspector.

***

some of that work near the top going horizintally looks like an afterthought.

12 posted on 03/23/2008 7:51:52 PM PDT by the invisib1e hand (Free New York)
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To: Mad_Tom_Rackham

Yes, they are ...but they apparently did not ?


13 posted on 03/23/2008 7:52:01 PM PDT by george76 (Ward Churchill : Fake Indian, Fake Scholarship, and Fake Art)
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To: Incorrigible

Looks like : over the years too many tons were added beyond what the bridge was originally designed to hold.


14 posted on 03/23/2008 7:53:21 PM PDT by george76 (Ward Churchill : Fake Indian, Fake Scholarship, and Fake Art)
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To: the invisib1e hand

I’ll wager that the bridge inspector caught it, but his or her bosses simply blew it off. (Of course, I am just speculating).


15 posted on 03/23/2008 7:54:07 PM PDT by 1rudeboy
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To: george76

But at least they got their light rail project funded!


16 posted on 03/23/2008 7:56:14 PM PDT by ikka
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To: Incorrigible
One article even noted that there was 191 tons of construction material piled on the weakest point of the bridge at the time of the collapse.

And all of it personally driven there by Dick Cheney at the behest of Halliburton.... (/sarc)

17 posted on 03/23/2008 7:56:31 PM PDT by gunservative
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To: kidd

Thanks for the head’s-up! (I wasn’t sure what I was supposed to be looking at either.)


18 posted on 03/23/2008 7:57:37 PM PDT by yankeedame ("Oh, I can take it but I'd much rather dish it out.")
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To: george76

Comments on an older related thread suggest that adding four additional lanes of traffic in 1988 may have contributed to the bridge’s failure.


19 posted on 03/23/2008 7:58:25 PM PDT by SpaceBar
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To: coloradan

AP is ok. Thanks.


20 posted on 03/23/2008 7:59:50 PM PDT by Admin Moderator
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To: 1rudeboy

but the steel would of had to buckle alot more then that if that was the cause of the collapse....

Its safe to assume that it buckled more with time until the collaspe(if that wa sindded the cause)...so why didn’t the inspectors look at these areas later


21 posted on 03/23/2008 8:00:18 PM PDT by janetjanet998
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To: the invisib1e hand

I do nuclear power plant failure analyses, not structures...but a bent gusset plate suggests a bad generic design, not a part failure.

I would’ve shut the bridge down immediately (regardless of the inconvenience to the public), called for a review of the stress analyses, a detailed inspection of other affected parts and a complete repair of all affected components. But thats how the nuclear industry works.


22 posted on 03/23/2008 8:00:32 PM PDT by kidd
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To: george76

And it was what, not four minutes before somebody said “Bush’s Fault!’ in the MSM...


23 posted on 03/23/2008 8:01:11 PM PDT by Old Sarge (CTHULHU '08 - I won't settle for a lesser evil any longer!)
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To: kidd

I wonder how commom something like that is on bridges


24 posted on 03/23/2008 8:04:55 PM PDT by janetjanet998
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To: george76

The first thing that came to my mind - is the engineer who designed the plates, must have believed that the number of rivets were more important than the THICKNESS and STRENGTH of the materials being riveted together..

In such a critical application - I’m shocked at the thinness of the plates used to secure the beam members...

I would want to see a plate at least 3 times the thickness used — if FIXING the members and prevent movement was the design objective...

Hell — it looks like they used a too thin plate and popped a few hundred rivets into it thinking the rivets would increase the the strength of the UNRIVETED expanses of the sheet.

What they accomplished was securely fastening a thin member between two shifting beams, and over time the FLEXING fractured the sheet, leading to a catastrophic failure and the whole assembly collapsed.

I’m surprised this design was ever proposed or approved by any Civil Engineer.....


25 posted on 03/23/2008 8:08:57 PM PDT by river rat (Semper Fi - You may turn the other cheek, but I prefer to look into my enemy's vacant dead eyes.)
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To: george76

After all this information, it’s amazing the bridge lasted as long as it did.


26 posted on 03/23/2008 8:09:48 PM PDT by Moonman62 (The issue of whether cheap labor makes America great should have been settled by the Civil War.)
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To: ikka
But at least they got their light rail project funded!

Priorities....

27 posted on 03/23/2008 8:17:55 PM PDT by TheBattman (LORD God, please give us a Christian Patriot with a backbone for President in 08, Amen.)
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To: kidd
But thats how the nuclear industry works.

guess we ought to be thankful it wasn't a nuclear bridge.

28 posted on 03/23/2008 8:21:31 PM PDT by the invisib1e hand (Free New York)
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To: river rat

It may have been Ok for the amount of weight in 1967...but like the article says they added more concrete over the years..

So can you even sue the orginal maker of the bridge? How is that their fault that 40 years into the future the thing was overloaded by more concrete and huge contruction equipment.


29 posted on 03/23/2008 8:21:32 PM PDT by janetjanet998
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To: kidd

>I would’ve shut the bridge down immediately<

and you would have been overruled by your superiors just as quickly.

Who the hell do you think you’re talking to? I am the Governor of this State! You will not close down a section of the freeway and cause economic disaster to my State! Now get out of my office before I have you arrested.


30 posted on 03/23/2008 8:29:23 PM PDT by B4Ranch ("In politics, nothing happens by accident. If it happens, you can bet it was planned that way." FDR)
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To: janetjanet998

I’m not a Civil Engineer - but BRIDGES should not be designed for the CURRENT anticipated loads...

Bridges must have a design life equal to the service life expectancy of the bridge — something like 50 years or more..

That damned plate looks so inadequate - it should have caught someone’s attention on the drafting board!


31 posted on 03/23/2008 8:32:41 PM PDT by river rat (Semper Fi - You may turn the other cheek, but I prefer to look into my enemy's vacant dead eyes.)
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To: 1rudeboy
The bends are not severe, but they indicate that there were forces on the plates that weren’t kosher.

Once the bending starts, it weakens the part immediately and extensively. Take a thin wooden or plastic plank, set it vertically and push on it. It will resist for a while, being still straight. But once it starts bowing, it takes very little additional pressure to fold it in half or break. That is because the pieces of the plank switch from compression load (which is fairly good) to bending and stretching, which for most materials is not good at all. Just imagine pushing on a vertical glass tube. Once the first crack starts, the part is lost.

32 posted on 03/23/2008 8:41:18 PM PDT by Greysard
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To: Post Toasties

“Whole lotta stupidity going on in this Socialist Paradise.”

— — —

yep. read my tagline.


33 posted on 03/23/2008 8:51:22 PM PDT by HighWheeler (The higher the concentration of libs, the bigger the tragedy that follows.)
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To: All

It was announced a while ago that the gusset plates were only half as thick as they were supposed to be.

http://enr.construction.com/news/transportation/archives/080115.asp


34 posted on 03/23/2008 8:51:59 PM PDT by ltc8k6
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To: ltc8k6; GladesGuru

Bingo!

See my post #25...

AH SO....it was SUPPOSE to be 2x thicker...

It’s encouraging to learn that my instincts are still relatively intact!

They got me home and they saw this screw up...

However — if they were suppose to be 2x thicker - then the prudent engineer would have added at least another 50% safety factor since this was a bridge in a FREEZING environment HIGH over WATER in a GROWING metropolitan area.....as part of the INTERSTATE HWY system.


35 posted on 03/23/2008 9:00:58 PM PDT by river rat (Semper Fi - You may turn the other cheek, but I prefer to look into my enemy's vacant dead eyes.)
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To: ltc8k6

“It was announced a while ago that the gusset plates were only half as thick as they were supposed to be.”

- - - -

So now the libs will go on a hunt for “The Culprit”.

The Culprit is defined as anyone that ever touched that bridge plus has deep pockets. And they can’t affect the next election.


36 posted on 03/23/2008 9:03:59 PM PDT by HighWheeler (The higher the concentration of libs, the bigger the tragedy that follows.)
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To: george76

Has this bent gussett plate the site of the initial failure in the collapse?


37 posted on 03/23/2008 9:04:03 PM PDT by Bean Counter (Stout Hearts...)
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To: george76
I said shortly after the bridge collapsed that if you've seen pictures of the bridge, it was essentially a disaster waiting to happen. Between the spindly and EXPOSED steel structure that was subject to the temperature and moisture extremes of the Minneapolis, MN area and the whole bridge being held up at four small points on a thin concrete piling, I'm surprised the bridge didn't collage years earlier.
38 posted on 03/23/2008 9:07:08 PM PDT by RayChuang88
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To: river rat
Yeah, they should have been at least as thick as the steel in the U-Channel or I beams, which looks to be at least twice as thick as those thin plates. After all they are expected to carry some of the load from those beams.


39 posted on 03/23/2008 9:09:28 PM PDT by HighWheeler (The higher the concentration of libs, the bigger the tragedy that follows.)
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To: janetjanet998

My BIL’s company - global engineering firm inspected that bridge in 2004(I think) and advised of needed repairs. The report is available on the web. Poor design compounded by incompetence. Can’t wait till theymanage our healthcare.


40 posted on 03/23/2008 9:13:38 PM PDT by sgtyork (The secret of happiness is freedom, and the secret of freedom, courage. Thucydides)
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To: sgtyork

“Can’t wait till theymanage our healthcare.”

— — —

That will collapse for the same reasons as the bridge: Poor initial construction and eventual overload.


41 posted on 03/23/2008 9:17:24 PM PDT by HighWheeler (The higher the concentration of libs, the bigger the tragedy that follows.)
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To: george76

Cripe, and I used to be scared walking over the old Washington Avenue bridge, back in the ‘40’s. I just knew it was going to come down.


42 posted on 03/23/2008 9:27:00 PM PDT by norge
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To: Incorrigible

Incorrect. The article said “more than 191 tons of construction material had been piled over the bridge’s weakest areas.”

It did NOT say the “weakest point of the bridge.” Big difference between the weakest point (singular) and the weakest areas (multiple unstated locations).


43 posted on 03/23/2008 10:37:34 PM PDT by JSteff ( This election is about the 4 or 5 Supreme Court Justices who will retire . Vote Accordingly!)
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To: george76

That amount of bend did NOT “cause” the failure (speaking as a registered professional structural engineer). It was not even a very good warning.

They say that the original design was flawed (gussetts half the thickness of what they should have been). If so, why did the MNDot approve to add additional lanes a few years ago. Did they not check the calculations when they approved that?

If the original design was flawed, why did MNDot allow it to continue in service when half of the thickness of some of the gussetts were rust (presumably they were then only 1/4 the thickness they needed to be at that time). Didn’t they check the calculations?

If the original design was flawed, why did MNDot decide to redeck the bridge, which implies that they expected the bridge to last another 15 years before replaceement. Didn’t they check the calculations?

The people who made the later decisions were more responsible for the collapse than the people who did the original designs. The later people approved heavier loads and a longer life than they should have. It if VERY obvious that the later people DID NOT CHECK THE CALCULATIONS before they made their desisions.


44 posted on 03/24/2008 6:42:31 AM PDT by jim_trent
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To: coloradan

They don’t look too bent, to me.


45 posted on 03/24/2008 8:27:25 AM PDT by expatpat
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To: Incorrigible

Now, that could do it....


46 posted on 03/24/2008 8:28:30 AM PDT by expatpat
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To: janetjanet998

Actually, I heard it reported that the plates were 1/2 as thick as they should have been for the bridge “as it was” when it was first constructed. So it was compromised from Day 1.


47 posted on 03/24/2008 8:55:32 AM PDT by Abigail Adams
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To: expatpat

It was years ago, so they had plenty of chance to bend more, and in any case, “not looking too bent” doesn’t mean the plates weren’t severly overstressed. They might have not supposed to bend at all, in which case any bend at all would have been way too much.


48 posted on 03/24/2008 8:57:39 AM PDT by coloradan (The US is becoming a banana republic, except without the bananas - or the republic.)
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To: coloradan

Oh, I don’t disagree. The point I was making is that the bending is a lot less than the headline suggested.


49 posted on 03/24/2008 9:30:28 AM PDT by expatpat
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To: expatpat

“The point I was making is that the bending is a lot less than the headline suggested.”

When steel takes on a permanent bend under load, which is not in the original design as as illustrated in the posted photo, it is telling the observant something. Unfortunately, there were no observant, or they were ignored, over ruled, ad nauseam.


50 posted on 03/24/2008 10:05:13 AM PDT by GladesGuru (In a society predicated upon freedom, it is essential to examine principle)
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