2001:'bridge should not have any problems with fatigue cracking in foreseeable future'

[Bluebear]

Fatigue Assessment of Deck Truss of Bridge 9340 TH I35W over the Mississippi River

'The research helped determine that the fatigue cracking of the deck truss is not likely, which means that the bridge should not have any problems with fatigue cracking in the foreseeable future. As a result, Mn/DOT does not need to prematurely replace this bridge because of fatigue cracking, avoiding the high costs associated with such a large project. The research also has implications for other bridges.'

http://www.cts.umn.edu/Research/ProjectDetail.html?id=1999014

[Maddy McCall]

1. "Avoiding the high costs associated with such a large project"

Yep.

:grr:

[Bluebear]

2. 'Analysis says Iraq war could cost $1 trillion'

http://www.boston.com/news/nation/articles/2007/08/01/analysis_says_war_could_cost_1_trillion/

[Maddy McCall]

8. "The research also has implications for other bridges."

:scared:

[Eric J in MN]

12. There is a line with an opposite meaning as of tonight. NT

NT

[DeposeTheBoyKing]

9. I was just thinking about that too

DAMN THE MISPLACED PRIORITIES OF THIS GODFORSAKEN CABAL OF CRIMINAL SONS OF BITCHES.

[Blue-Jay]

3. Looks safe to me for another couple of years.

Translation: Fuck it. Let's save some money.

[HiFructosePronSyrup]

4. Robert Dexter...

He didn't used to run a thoroughbred horse association, did he?

[thunder rising]

5. That's a serious hit for UMN.

Any other studies done or did that one give the "right" answer and that was the end of any studies?

[Kutjara]

6. "Foreseeable future" is one of those wonderful phrases.

It stops being the foreseeable future when something unforeseen happens, by definition. The "forseeable future" therefore ends anytime after about one second from when the phrase "foreseeable future" is uttered. I'm never comforted by people's ability to foresee the future.

[karlrschneider]

13. Yeah, well, I'm of the opinion that there is no such thing as "forseeable future."

Well, I guess it's relative...we can assume with a probability of about 99.999999999999999999% certainty the sun will rise tomorrow, I guess, but it isn't held up with steel trusses...

[malaise]

15. Norm Coleman is covering his tracks

or attempting so to do. He said the bridge was last inspected in 2004 and was in good shape.

[malaise]

7. Dan Abrams said the 2006 report

suggested that they monitor fatigue stresses on the bridge.

[Eric J in MN]

10. How did you find that? NT

NT

[Bluebear]

17. Here is the complete report in pdf format

http://www.lrrb.org/pdf/200110.pdf

[Eric J in MN]

22. But did someone else link to it on a blog, or...

...what made you go to that website?

[Bassic]

11. Yeah, but

9/11 changed everything...

[KitchenWitch]

14. I hope the fine people who wrote that report choke on their words.

x(

I am so angry and sad.

So far I have heard that 50 cars went into the river. 3 known fatalities and hundreds of people injured.

:grr:

And some of them may be my friends.

[dflprincess]

16. Per Normie Coleman who has spoken to the Secretary of Transportation

the Transportaion Department hasn't inspected the bridge since 2004. As the bridge was part of the interstate system, they would have some responsibility for its maintenance.

[malaise]

18. Olbermann is back on on MSNBC

discussing cracks reported last year with an Engineer.
James Burnett, former NTSB Chairman, on now.
Add.

[Gregorian]

19. This is a theoretical evaluation of the structure. And some historical background.

"Concern about fatigue cracking in the deck truss is heightened by a lack of redundancy in the main truss system."

"The peak stress ranges are less than the fatigue thresholds at all details. Therefore, fatigue cracking is not expected during the remaining useful life of the bridge."

I am assuming that the later quote refers to infinite fatigue life.

I'm still reading the documents, but it sounds like they've made assumptions in lieu of thorough visual inspections. Both are needed for a real evaluation.

There have been fatigue issues with the approach spans.

The paper discusses the possible failure due to lack of redundancy. They are somewhat vague about what could happen. And rightly so. It's a complex dynamic situation under failure.

As I mentioned in other posts here, corrosion is a concern. They say that pigeons roosting caused corrosion and were supposedly prevented from nesting in the bridge structure. But you can imagine how effective that would be. These are the little things that cause big trouble.

They did inspect the bridge for fatigue cracks in the main members.

I have to wonder if possibly any pile driving in the immediate vicinity could have raised the stress levels, with a full load on the bridge at the time, to a point where a weak point on the structure failed.

Maybe they had data collection in progress while the failure occurred. That would make this tedious task much easier.


Edit- Aha. The pile driving comment apparently is not the case. MSNBC mentioned it, but I'm hearing there was no such thing going on in the immediate vicinity.

[Junkdrawer]

20. Check out page 29 of the report (37 of the PDF)...

[Gregorian]

21. I saw that. And I doubt it's an isolated incidence.

That's where the lack of structural redundancy and unconservative design become even more critical.

I remember my materials engineering prof. giving his slide show after traveling the US, inspecting bridges. It's amazing what is out there. And that was the late eighties. Man, twenty years later things must be a bit worse. Entire beams corroded all of the way through. This is a very big problem in this country.

About the best thing I can say is that this is another argument against military spending. I'm much more afraid of structural integrity of our country's roadways than some band of Muslims running all the way over here and tossing a dirty bomb into the financial district of New York. Both are bad scenarios, but one is actually happening right now. The other doesn't affect the entire country.

But we still don't know what caused the bridge collapse. We will. But at a far greater cost than has we been investing in constructive rather than destructive actions. I guess you can tell I'm not big on military spending.

[KT2000]

23. Wonder if this is a report

that came up with desired conclusions like the * administration has done so often.
Cash and carry science of this administration has infected all levels of our society. Guess we can expect to see more disasters.

[Eurobabe]

24. BushCo priorities: Iraq, not US infrastructure,

get used to it. I've seen this in countless states. Bridges, overpasses and roads are a disaster waiting to happen.

[B Calm]

25. and Bush's EPA sees no problems in the foreseeable future and allows

BP to dump mercury into Lake Michigan..

[malaise]

26. Oh Oh!!!

http://www.startribune.com/10204/story/1338970.html

[JTFrog]

27. So in 2005

it was rated structurally deficient, but Gov. Tim Pawlenty said Wednesday night that the bridge was inspected in 2005 and 2006, and that no structural deficiencies were identified.

Maybe he should have stuck with the republican chant of I can't recall if there were deficiencies or if I was told about them.

I saw someone link to an Onion article that was rather chilling to read last night. Obviously satire, but so much truth in that satire, it's scary.

[malaise]

29. Pawlenty is going to get what's due n/t

[qdemn7]

28. Harmonic resonance??

Could the jackhammering being done on the bridge set up enough resonance to cause the bridge to fail? I'm no engineer, so that's why I'm asking.