aftermath debris, and reading the UofM report on their 2001 inspection, I owuld theorize that one of the south-side approach sections collapsed, pulling the central steel-arch sections off its supports (one end was pinned, the other supported on rollers), followed by slow collapse of the remaining now-overstressed sections.
Richard Henry wrote in news: snipped-for-privacy@x35g2000prf.googlegroups.com:
Photos of the main bridge span show that it isn't terribly robust; there were four support steel and concrete columns that didn't appear very substantial for a span of that length. I'd prefer a design that would fail more gracefully.
We'll have to wait for the failure analysis, as usual. No doubt there are many, many potentially marginal bridge designs like that. Lowest bidder, underfunded, etc.
--Damon
The failure will, no doubt, be blamed on GWB, or his administration, or something similar.
Though it was clearly built during a retarded leftist weenie's administration ;-)
Seriously, We have MANY ancient bridges that may plummet at any moment, because very little maintenance has been done on them.
Since it happened in my old backyard, I am intimately acquainted with the "Silver Bridge" collapse at Point Pleasant, WV, in 1967, interestingly on another route 35, US35 instead of I35.
My wife to be and I drove across there regularly to a beautiful park on the WV side of the Ohio River.
...Jim Thompson
--
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC\'s and Discrete Systems | manus |
| Phoenix, Arizona Voice:(480)460-2350 | |
| E-mail Address at Website Fax:(480)460-2142 | Brass Rat |
| http://www.analog-innovations.com | 1962 |
America: Land of the Free, Because of the Brave
It has happened before and will happen again. People learn. Than they learn to forget.
--
Boris Mohar
Even brand new ones are outright scary. A few weeks ago I came back from a client (Bay Area, California) and Berkeley was all plugged up like usual. So I went east of the hills and the over the Martinez bridge. Now I am not the squirmish kind of guy but I did grab the steering wheel tightly. The "railing" between the lanes and death consisted of barely more than the concrete barriers in construction zones and this bridge is about 150ft above the water. Should a motorcyclist lose control and hit that barrier he'll either hit the water at high freefall speed or hit the rusty metal of the old railroad bridge that's next to the new span and much lower.
-- Regards, Joerg http://www.analogconsultants.com
**Biting my tongue as hard as I can** 8-)
It will be interesting to see if the design and/or construction was/were primary causes.
Bingo (I think). How many existing structures could have been brought back to spec with what was pissed away on Ted "a series of tubes" Stevens'[1] "Bridge to Nowhere"? . . [1] It will be interesting to see how his investigation shakes out as well.
No reports of a guy with a beard and a turban with an acetylene tank on his back climbing around in the trusses?
Tony Snow is apparently anticipating that and has already blamed the State of Minnesota for shoddy maintenance.
Might be worth looking at the train that was passing at the time. Vibration from it, or maybe it even clipped something.
-- Tony Williams.
Civil engineers have been warning for many years that bridge preservation work in the US is urgently needed, there are an enormous number of bridges of all sizes that are technically unsafe or becoming so. A tragedy like this has been expected, sooner or later.
Something triggered the collapse- perhaps the train, jackhammers on the bridge, traffic patterns or whatever, but I suspect that happenstance is unrelated to whatever weakened the bridge to that point in the first place.
Best regards, Spehro Pefhany
-- "it\'s the network..." "The Journey is the reward" speff@interlog.com Info for manufacturers: http://www.trexon.com Embedded software/hardware/analog Info for designers: http://www.speff.com
I heard as probably most of you have by now - that bridge was suspect in
1990 (Corroded is what I heard). Makes one wonder why now - that truth is coming out! I don't know about all the states - but PA's Dept of Transportation went on TV to talk about their "Inspections" of bridges here. About a year ago or so - there was an "over pass" which had collapsed onto a major stretch of highway. No one really got hurt - but that was our first here that I know of. The reason I "believe" was "Stress". The Concrete gave out.
I wonder when they tell us that Halliburton built all these bridges...? :(
Very sad to hear about the loss of life. Could have been any one of us.
I am also wondering if it's time to shift some investment dollars to the makers of carbon fiber (lighter, stronger than steel, easy to apply to reinforce bridges...) OK, maybe not "easy", but staightforward. Or Kevlar wraps like they use in earthquake-prone areas to keep the concrete from spalling....
-mpm
The train was running under the northern approach spans, which appeared to be the last to fall.
I don't want to start any unsubstantiated rumors, but I did hear on the news that they were driving new piles in preparation for (they did not say). MSNBC or less likely CNN (regular). [I never watch FOX] IF that is true, then vibration or liquefaction at the foundations could also be an issue.?
Curiously though, after this one mention, I did not hear this pearl again on any coverage. !!? It was parrotted as fact, not the (unfortunately "usual") hype by anchors/reporters. Not that the delivery is important. Later, I heard they were just mopping up from repairs. Who knows what to believe these days?
The investigation should help, but I agree, it doesn't look from the photos I've seen that the train had anything to do with this. My knee-jerk reaction, which is more often right than wrong, tells me this was both a maintenance issue and a substandard design (re- design?) issue. Perhaps that the bridge was modified (lanes added) outside it's original design and the add-on engineering took some unwarranted / ill-advised "risks".
I doubt this was originally built as an 8-lane bridge 40 years ago, but I could be wrong.??
-mpm
The news mentioned that the bridge fell on top of a train. In the news footage, including lots of helicopter footage, they didn't clearly show the relationship between the rail line and the bridge.
I suppose they'll be looking into the possibility that one of the bridge supports might have been struck.
Other than that, the general poor condition of the bridge is probably due to road salt. Over here in the Pacific Northwest, the use of salt used to be rare (as is the incidence of ice/snow). But it has been on the increase lately. Most of our bridges are steel reinforced concrete instead of exposed steel structures. The latter can be inspected for corrosion more easily. The former will be falling down at an increasing rate as the internal steel rots away.
-- Paul Hovnanian paul@hovnanian.com ----------------------------------------------------------------------- There is no place like 127.0.0.1.
Jeezis Aitch Fuck, Thompson, do you have to throw your political insanity into EVERYTHING?
You say, "They'll blame the Bush administration, but it's REALLY the fault of the liberal weenie", as you turn around and do exactly what you're accusing "them" of.
You need some serious medical attention.
Good Luck! Rich
This bridge was equipped with spray de-icers about 5 years (or more) ago. No salt.
I spent a lot of time in and about this bridge when I was at the University of Minnesota. There is/was a research lab right under the bridge (Williams/Tandem Lab) which I worked at in the late 60's for a while (etching PCBs in fact).
The rail line is not a high traffic or even high speed line. It is simply a long siding coming out of Union Yard that provides access to the the University Power plant and other industries on the north side of the river (Metal-Matic for one) Originally, it had been part of the Burlington Northern's main line from Chicago, around Union Yard and across the Stone Arch Bridge to the main rail station in downtown Minneapolis. That has not been used for maybe the last 20 years. Two sets of rail cars were crushed. One was a tanker of some kind on a separate track, the other a jumbo covered hopper/s on the track closest to the river.
The northern end of the bridge passes over 2nd Street SE and the rail road tracks before it meets the main span of the river bridge. Supports for this segment were conventional heavy concrete supports like those used for Interstate bridges.
Regards,
Blakely
-- Blakely LaCroix Minneapolis, Minnesota
Wow, amazing pdf link! great detail! The reason the bridge collapsed is obvious and fully suppored in the 2001 report, even though the autrhs came to a different solution.
1) The bridge did fail, therefore the statisical analysis, ie time to failure and the data taking excersize, were wrong. 2) The stress one obtains (boh theory and actual depended on the exact loaction and distribution of vehicle . Furhter, "truck" are limited to 10% of the load. Not sure what a 1967 truck and a 2007 truck are? 3) loading depanded on the concrete skin being in place, as the bridge is jus a skelton of undersized stell, the skin add stability by distirbution loads and tightening things up. the bridge had part of the skin rmoc\\ve for re-surefacing. 4) the highest variations in loading is whether and the point where the roller bearings join. Note in this report but in another (need ref) th roler beraings had since corroded, limited stress relief! 5) there was a measure 36-38 MAP stress in asystem where 42-46 Mpa is the failure point. This is a relatively smal ratio of "overdesign" from my POV. I am formally trained in EE and this seeams like using a 48 volts electrolytic cpacitrs in a circuit where 28 volts is normally seen, and a time there are 38 volt spikes and I am trying to statitcially predcit exacly when the cap goes "bad".. The stakes are soooo much higher in a bridge then even consumer electronics.. I would use 90 volt caos and try not use electorlytics, but this bridge looks like a fragile peice of crap, under dsign poorly built, the locals offcial knew thie fr decades and droped the ball. SadMarc Popek
innews: snipped-for-privacy@x35g2000prf.googlegroups.com:
Design a better one.
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