I have friends in Burnsville, MN, and I can’t count the times I’ve crossed this span. No point in duplicating what is readily available in the mainstream, but if you’re interested in blog coverage, my recommendations are Powerline and Captain’s Quarters, both based out of Minneapolis.
More from Minneapolis: Captain Capitalism is alive and has the pie charts to prove it.
Blog of a guy who watched it fall from his apartment window. Pictures, blow by blow account. Better coverage than CNN for my money.
http://www.blanked-out.com/
There’s footage of the actual collapse, from a security camera, available here:
video.google.ca/videoplay?docid=-1679165646933842788
It is a very, very dangerous thing for engineers to be wrong.
eugene – who says that the engineers were wrong?
We still don’t know the reasons why the bridge collapsed – although Daily Kos is assuring us that it’s all “Bush’s fault’ – presumably because of cut-backs in funding. How cutbacks in funding lead to a collapsed bridge is beyond my limited understanding. After all, that assumes that without those cutbacks, the bridge would have been immediately rebuilt. Is this a valid conclusion?
From what I can gather, the engineering recommendations on this bridge were exactly similar for many of the bridges across the country, and the terminology meant only that the bridge should be replaced in a few decades. Not that it was in danger of imminent collapse.
Not all contingencies can be foreseen, by anyone, even by the wisest engineers. So, I think we’ll have to wait for the reports.
I have to comment, however, on Daily Kos – a site I’ve rarely visited – the vitriol, in particular of the moderators, who insert commentary after almost every post – is quite astonishing. The comments are mundane repetitions, irrelevant to the issue – ie, ‘impeach Bush’…etc.
Daily Kos isn’t a blog site but a cult site.
bridges are least stable under construction or under repair. this was under repair. once constructed and operating , they use opposing forces to be stable.
this is part of the iron ring ceremony, do not blame the iron and stone, but blame the man.
ET: I don’t know if this is the same thing you’re reading, but I read that the bridge was certified in 2006 as having no structural defects. Presumably this analysis was carried out by engineers.
eugene – wait for the report.
cal2 – I’m not sure of your point. Anything that is ‘in transition’, ie, being built or ‘being transformed’ ie, repaired, is – relatively – unstable. I repeat, relatively unstable. The relativeness refers to whether the building or repairs are structural or superficial. For example, I very much doubt that painting the walls of my house are going to affect the structural nature of that house.
The current repairs were, to my understanding, superficial or surface rather than structural.
To my understanding, the engineering reports were that rebuilding, ie, structural repairs, were not necessary at this time. But, I think we have to wait for the report. There’s only so much speculation one can do – and enjoy.
ET – I think you are missing my point.
If a bridge was certified as safe and it collapsed, clearly the certifying engineer(s) was wrong. It was not safe. Why the bridge, in fact, collapsed is irrelevant.[1]
[1]Unless, of course, it was caused by something extra-structural, e.g. a bomb, in which case it would be implied that the safety certification did not extend to bridges collapsing due to intentional explosion.
Eugene, what I had heard was that it was reviewed (probably a full inspection) in 2004 and had received “a clean bill of health” (whatever THAT means…it was uttered by a politician who is likely in CYA mode). It was reviewed a couple years prior by the Army Corp (I believe) who noted “structural deficiencies” (unnamed and not defined as to severity).
There was “construction work” undertaken the preceding night on the substructure. My first thought would be negligence on the part of the construction contractor…once that is ruled out, I’d move to the inspection engineer.
Steel structures are prone to fatigue failures and these cannot be readily “seen” through inspection.
As ET suggests…wait for the forensic engineering reports to come out before casting the first stone.
Who out there has never had second thoughts while crossing a large bridge?
As somebody who lives in a community with dozens of bridges,I can only say this is a nightmare come true.
Vit…thanks for the good link.
It will be fascinating,to say the least,to learn the cause of such a catostrophic failure.
Clearly Eugene … you are leaping to conclusions!
Are you an engineer? Have any training in physical sciences?
BTW – I’ve been over that bridge a few times myself …. sometimes at rush hour! Now just imagine being stuck in traffic and having the floor drop out from under you!
Slightly OT – CBC news in their usual oh so competent reporting described the bridge as an “Interstate” span today!
It is in no way spanning states!
It happens to be part of an interstate road ….. oh well details…..
I am not an engineer, but the before pictures show an awfully flimsy under-structure for an 8-lane bridge that is a main artery. It will be interesting to find out exactly what made it come down.
,
http://today.reuters.com/news/articleinvesting.aspx?type=bondsNews&storyID=2007-08-02T173957Z_01_N02464869_RTRIDST_0_BRIDGE-COLLAPSE-UPDATE-4.XML&pageNumber=2&imageid=&cap=&sz=13&WTModLoc=InvArt-C1-ArticlePage2
The bridge had passed inspections the past two years, Minnesota Gov. Tim Pawlenty said, though it was among thousands of bridges across the country deemed to be “structurally deficient” in a 2005 U.S. government report.
“(The rating) was by no means an indication that the bridge was not safe,” U.S. Transportation Secretary Mary Peters said at the scene. “None of those ratings indicated there was some kind of danger here.”
And the conspiracy whackos are starting to mobilize already.
http://www.damianpenny.com/
From Captain’s Quarters:
“The power of the Digital Age started showing itself in the first hours of the tragedy. News organizations found reports on prior bridge inspections on the Internet, one of which noted the bridge “has many poor fatigue details on the main truss and floor truss system.” Other reports came to light shortly afterwards, including more recent inspections that classified the bridge as “structurally deficient.””
“State officials quickly clarified that engineers didn’t recommend any immediate action as part of those inspections, but the issue will not disappear quietly.”
. . .
“With 80,000 American bridges classified as structurally deficient, as was the one that collapsed here, every state will have to answer for its infrastructure maintenance … and Minnesota actually was better than most in that regard before this catastrophe.”
CNN boasts “video” of bridge collapse —- a video of “a family trying to stay positive while awaiting woman’s fate “.
Discusting and sicko. Also fits the ‘adapt or die’ thread.
http://edition.cnn.com/2007/US/08/02/bridge.collapse/index.html#cnnSTCVideo
oh, Im actually guessing its an engineering problem , the bridge was under repair. and like I said the bridges and buildings are most unstable under repair or under construction. A great part of a building strength now comes from its outer shell, witness WTC or your house or your unibody car where even the windshield is part of the stiffness of the vehicle. fatigue points to an under design, on bridges usually the toughest part isnt the holding them up, its the decking leaking an corroding the structural steel. so a superficial fix of the deck may have had underlying problems.
the iron ring ceremony is only understood by half of the readers at SDA. and until you read this and the quebec bridge, you wont understand either.
blame not the iron or the stone ,but the man.
http://en.wikipedia.org/wiki/Iron_Ring
My prayers go out to all the families of the hurt or those who lost loved ones…
ET, clearly Bush used some of that alien technology they have stored at Area 51 to travel back in time to 1967, where he SABOTAGED the building of this bridge. You just need to know how these people [B]think(?)[/B].
For the record, the Iron Ring ceremony (I have one) is not a designation as a Professional Engineer (I am not). I can’t say whether or not the bridge was flimsily designed and/or built, I am not a bridge engineer and I have no trustworthy data at hand.
I do not have second thoughts driving over bridges, at least not in countries like Canada and the USA. Certainly the media and the hand wringers will attempt to string this out for maximum sales and political benefit, yet exactly what percent of traffic deaths is caused by bridges collapsing?
Average humans have roughly zero ability at risk analysis, even professionals find it a difficult business. I think I too will wait for the engineering forensics report, the NTSB should have it at their web site in a couple years. Learning from mistakes is a good thing, ululating over them is not.
By the way, there is a video of my office “floor dropping out from under me” at work (although at a slower speed) at the 00:50 mark here: tinyurl.com/2hdydo 😉
Cal2 … you are describing a Maintenance problem!
There are so many what if scenarios to a systems failure ( the bridge being a structural system ) it’s pointless to speculate!
But if asked to speculate I’d say that the problem lies in an administrative decision regarding maintenance costs. Just guessing!
“blame not the iron or the stone ,but the man.”
Vitruvius…
“Learning from mistakes is a good thing, ululating over them is not.” Excellent comment!
OMMAG, I do believe you are trying too hard to dis the CBC. The bridge was part of the Interstate highway system, namely I-35, and as such was an interstate highway bridge.
yes , the iron ring is handed out around graduation, I have one, dont wear it , an’ I are a professional ingineer,
but I am 32 years past building bridges- my first job.
note that most bridge failures- Second Narrows, Quebec cantilever (where the iron ring was originally wrought)were at construction or during maintenance – Calgary Bearspaw and this one. nothing like taking out support and hanging things on scaffolding to reduce the 4x safety factor.
blame not the iron or the stone , but the man.
Rudyard Kipling wrote the ceremony , it has Masonic parts for you conspiracy theory types.
I seem to recall a structural engineer whose job was building bridges stating that the use of term “structural deficient” was extremely misleading,as it could mean anything from some normal rust spots to immediate closure of the bridge. In other words,lets wait for the report before we going blaming the pilot(engineer)
I remember a buddy of mine , inspecting a wall that he wanted repoured. he scratched across it , NFG!!! with a crowbar.
when the contractor came back enraged , he thought he was going to get beat up and said it meant NOT FIRST GRADE. dont know what happened to that wall or if it was ever repoured. gubmint job ya know.
stuff should never fall down in quebec, according to the invoices , there is always three or four times the amount of concrete used then estimated.
Hmm, I can’t find any reference to “blame not the iron or the stone, but the man” anywhere, it’s certainly not in The Obligation. I’m also not sure where the Masons are involved here either, though I’m not a student of them.
The Ritual of the Calling of an Engineer
by Rudyard Kipling
“The Obligation
“I _____, in the presence of these my betters and my equals in my Calling, bind myself upon my Honour and Cold Iron, that, to the best of my knowledge and power, I will not henceforward suffer or pass, or be privy to the passing of, Bad Workmanship or Faulty Material in aught that concerns my works before mankind as an engineer, or in my dealings with my own Soul before my Maker.
“My Time I will not refuse; my Thought I will not grudge; my Care I will not deny towards the honour, use, stability and perfection of any works to which I may be called to set my hand.
“My Fair Wages for that work I will openly take. My Reputation in my Calling I will honourably guard; but I will in no way go about to compass or wrest judgement or gratification from any one with whom I may deal. And further, I will early and warily strive my uttermost against professional jealousy and the belittling of my working-colleagues in any field of their labour.
“For my assured failures and derelictions I ask pardon beforehand of my betters and my equals in my Calling here assembled, praying that in the hour of my temptations, weakness and weariness, the memory of this my Obligation and of the company before whom it was entered into, may return to me to aid, comfort and restrain.
“Upon Honour and Cold Iron, God helping me, these things I purpose to abide.”
(My copy is dated 1977-03-06, signed at Camp 6.)
Perhaps bridges should have a higher priority than “fighting” a possible, possible one degree Celsius rise by later this century.
Don’t forget Captain Capitalism is from Minneapolis, Minnesota:
http://captaincapitalism.blogspot.com/2007/08/minnesota-state-budget.html
Virtuvius,
I believe you should not be publishing that. I got my ring in 2006 and I distinctly remember is being a secret that wasn’t to be shared with people who took the oath. neither my mom (nurse)nor my brother (biochemist) were allowed in but my dad (mining engineer) was.
I suggest you ask Kate to take it down.
From wiki:
Although the details of the ceremony are not secret, they are considered sacrosanct and obligated engineers normally do not discuss the ceremony, even with engineering students.
http://en.wikipedia.org/wiki/Iron_Ring
Next time please show some respect.
It is my first-hand understanding, Jon, pace Wiki, that attendance of the ceremony is one thing, but the Obligation itself is not secret. No such secrecy was mentioned when I signed, or I would not have. I don’t belong to secret organizations, as a matter of principle (indeed, I joined ΔΥ, an explicitly non-secret fraternity, originally founded in 1834 to fight the domination of university politics by secret fraternities).
My framed signed copy of the Obligation is on my office wall beside my degrees, which anyone who visits my office is welcome to read. And it’s available via tinyurl.com/39g7jg – so even if the cat was in the bag, it is no longer rebaggable.
My respect for engineers and engineering elucidated here over the last few years at SDA is well known, but it depends on their actual history of trustworthyness, not on some sort of formal obligation, lovely though it is.
Jon,
The Obligation, as well as descriptive outline of the ceremony are readily available within a few seconds search on the www. However, I appreciate your commitment to your studies and profession, and will end my comment at that.
Cheers
OMMAG: trying as hard not to jump to conclusions as possible (I’m from the computing sci part of things, not so much engineering). The only thing I was trying to say was that if someone said it was safe and it collapsed, clearly they were wrong.
That, and read my original comment again. “It is a very, very dangerous thing for an engineer to be wrong.” That’s a compliment, I don’t know if you noticed. It’s more of a testament to their importance that they absolutely have to be right.
Well said, Eugene: if someone said it was safe and it collapsed, clearly they were wrong. It remains an open question as to whether or not engineers said it was safe. Based on the admittedly limited value of the information available so far from the various sites I have read, apparently the engineering reports over the last few years gave the bridge a degraded rating, for some value of degraded.
Alas, as far as I can tell, whether or not a so-valued bridge is considered safe is a matter for state DoT politicians, managers, and risk analysts. It is my understanding that in such a context engineers are essentially considered expert witnesses, but they are not allowed to be judge and jury. Unfortunately, engineers are not in charge 😉
AL GORE and th eco-wackos will blame this on GLOBAL WARMING knowing how rediclous they are
No they won’t, Plover, there’s no money in that for them.
Henry Petroski’s ‘To Engineer is Human: The Role of Failure in Successful Design’ (1985) points out the importance of attention to detail design in construction and fabrication.
The one case I am reminded of is the collapse of the Kansas City Hyatt Hotel walkway on New Years’ Eve, 1981.
Forensic engineering discovered that “The original design had floor to ceiling continous rods holding up all the walkways. The contractor decided that it would be too hard to build them that way, so he suggested a design change in which the rods went to the upper walkway, then another set of rods went from the upper to the lower. The engineers did sign off that change. The failure seemed to occur because of the moment applied to the beams in the upper walkway because of the offset between the rods going up and the rods going down.”
Careful attention to detail is also just as necessary when it comes to regularly-scheduled maintenance otherwise potential problems can end up just getting superficially fixed, hiding the core problem. I think someone else here has mentioned this already.
Sometimes infrastructure maintenance budgets get cut for political reasons and sometimes important decisions get made without careful thought or HAZOP-style analysis. And then sometimes people die as a result.
[Disclosure: I’m currently working as a design checker, but not for bridges or buildings.]
Not to belabour the point, but if someone inspected the bridge and said it was safe AND THEN A CONTRACTOR SCREWED WITH THE BRIDGE THE NIGHT BEFORE THE COLLAPSE, then it isn’t the inspector’s fault. Again, we’ll have to wait for the forensic report
…but having said that, my money is on metal fatigue as the culprit.
one of the best failures was the mall in Vancouver. Jimmy Pattison was cutting the ribbon when the roof fell in, couldnnt have done better with special effects in a movie. someone had decided to put parking on the roof, then landscaping without telling the structural engineer. A few days of fine Vancouver rain and the whole thing doubled in weight, combined with the live load of a frontend loader and down it came. I can still see Pattisons face as the ceiling crashes in the background.
The bridge was inspected in 04, 05, 06, and was undergoing inspection when it collapsed. Repairs were only being conducted to the deck surface, which wouldn’t affect the strength of the bridge. As to the “flimsiness” of the superstructure… it wasn’t. It was susceptible to failure since there were no backup supports so that one corner going down would take the entire bridge down.
Given that this was a multi component bridge with concrete only as a flat member, the bridge deck would have had no structural component. Concrete has roughly no strength in tension, and rebar can only help so much. The design life of the superstructure is much, much longer than that of the deck, and so no designer would have relied on the deck for anything.
What’s likely going to result is another example of how visual inspection is insufficient for verification of structural integrity. Yesterday’s closure of a bridge in Montreal to trucks thanks to a core sample that had previously been “unaffordable” (thanks to villainous union policies) is a great instance of this as well.