That Bridge in Minneapolis

When I first saw that bridge in Minneapolis under construction, where it was going up just a few blocks upstream from the grand old Tenth Avenue Bridge with its classic contours of open spandrel arches, tried and true to the test of time as the aqueducts of Rome, I couldn't but stand there and wonder why on earth they were putting that new, totally shitty looking bridge in over the river--and right there of all places.
Well! As of that date, when the bridge was nearing completion in 1967, the I-35W expressway that it was being built to serve, had not itself as yet come anywhere near to that site. The freeway still remained to be bulldozed through the whole breadth of a then as yet sedate and really quite pleasingly laid-out downtown Minneapolis cityscape, so richly adorned as it then way by the art nouveau architectures of La Belle Epoche with those stately old boulevards planted with elms and flowers, statuary and benches where two major thoroughfares came together, flowing into the downtown Loop past Mount Curve, around all the magnificent old cathedrals, the Tyrone Guthrie theatre, the Walker Art Center and Loring Park.
No! I hadn't the foggiest idea of what the future held in store via the agendae of those city planners, so far as a huge, rumbling, crushing, crumbling invasion of I-35W to come smashing its way through it all, so I couldn't for the life of me imagine why anything so ugly as that horrid green bridge . . .
http://www.visi.com/~jweeks/bridges/pages/ms16.html
. . . should even so much as be there to stand in such ugly redundancy to something so elegantly monumental as this . . .
http://upload.wikimedia.org/wikipedia/commons/d/d0/Minneapolis-Panorama-2006-10-20.jpg
It doesn't take long to discover through a few quick searches exactly what went wrong in the design of that horrid looking too big for its britches, nasty green bridge. Or just skip the searches and trust to your eyes as you look at the photos. Now, if you were a terrorist with a mind to take that new bridge down, simply ask yourself what a few small well-placed charges could do as your eye catches sight of those four puny points, all that are holding it aloft! See for yourselves where the cantilevered steel trusses come down to make contact with those shockingly spindly looking piers, for the God's sake.
As a quick visit to http://tinyurl.com/34r5uy will show, you may observe that while, "A spandrel-braced arch or open spandrel deck arch carries the deck on top of the arch . . . some metal bridges which appear to be (the) open spandrel deck arch are, in fact, cantilever; these rely on diagonal bracing. A true arch bridge relies on vertical members to transmit the load which is carried by the arch."
Can there be any replacement for the true arch? I am no civil engineer, nor any kind of architect, but something of pure intuition is telling me there must be some quite possibly as yet unfathomed strength of support that comes by a mystery of Cartesian magic in the geometry of the unbroken contour of a curve. Some kind of grand leverage going on there toward a purpose of uplifting things and holding them up, even over the centuries. Just seems there's something in the fact that the Coliseum is still standing that serves a fair amount of support toward that conclusion.
The false arch of cantilevered steel construction that was thought to be very 'state of the art' for I-35W quite clearly has not proven to be quite the smart, fresh, with-it idea as its schemers had thought, seeing how it could not even so much as begin to stand up to "the bridge considered the crowning achievement of Minneapolis city engineer Kristoffer Olsen Oustad" as built between the years of 1926 to 1929 to stand the test of time.
http://en.wikipedia.org/wiki/Cedar_Avenue_Bridge_(Minneapolis)
And you have all seen it in the newsfilm, Oustad's bridge, the 10th Avenue Bridge, the "Cedar Avenue" bridge, it's all the same one, standing there yet, strong and serviceable as ever beside the wreckage of the fancy "new" idea.
When I stood there that day on my way home from campus looking out over the river to see the way the builders of that new bridge had seen fit in their hubris to design their construction as to seemingly dwarf (in mere terms of height and breadth) the appearance of the old solution, I was not impressed.
No. I was just not impressed.
I am still not impressed.
--
Mackie
http://www.mackiemesser.zoomshare.com/0.html
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[...]

Well now. That didn't take long at all.
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Subject: The Bridge of San Luis Minneapolis Date: Thursday, August 02, 2007 2:41 AM
When I first saw that bridge in Minneapolis under construction, where it was going up just a few blocks upstream from the grand old Tenth Avenue Bridge with its fine old classic concrete contours of open spandrel arches, tried and true to the test of time as the aqueducts of Rome, I couldn't but stand there (in my bliss of ignorance) and wonder why on earth they were putting that new, totally shitty looking bridge in over the river--and right there of all places.
Well! As of that date, when the bridge was nearing completion in 1967, the I-35W expressway that it was being built to serve, had not itself as yet come anywhere near to that site. The freeway still remained to be bulldozed through the whole breadth of a then as yet sedate and really quite pleasingly laid-out downtown Minneapolis cityscape, so richly adorned as it then was by its La Belle Epoche art nouveau architectures of . . . Ah! I remember it so fondly with those stately old boulevards planted with elms and flowers, statuary and benches where two major thoroughfares came flowing together past Mount Curve, round all the magnificent old cathedrals, the Tyrone Guthrie theatre, the Walker Art Center and Loring Park.
No! I hadn't the foggiest idea of what the future held in store via the agendae of those city planners, so far as a huge, rumbling, crushing, crumbling invasion of I-35W to come smashing its way through it all, so I couldn't for the life of me imagine why anything so ugly as that horrid green bridge . . .
http://www.visi.com/~jweeks/bridges/pages/ms16.html
. . . should even so much as be there to stand in such tasteless redundancy to something so elegantly monumental as this . . .
http://upload.wikimedia.org/wikipedia/commons/d/d0/Minneapolis-Panorama-2006-10-20.jpg
It doesn't take long to discover through a few quick searches exactly what went wrong in the design of that atrocious looking too big for its britches, nasty green bridge. Or just skip the searches and trust to your eyes as you look at the photos. Now, if you were a terrorist (of which there have been a few around the old town of late) with a mind to take that new bridge down, simply ask yourself what a few small well-placed charges would do as your eye catches sight of those four puny points, all that are holding it aloft. See for yourselves where the cantilevered steel trusses come down to make contact with those shockingly spindly looking piers, for the God's sake.
As a quick visit to http://tinyurl.com/34r5uy will show, you may observe that while, "A spandrel-braced arch or open spandrel deck arch carries the deck on top of the arch . . . some metal bridges which appear to be (the) open spandrel deck arch are, in fact, cantilever; these rely on diagonal bracing. A true arch bridge relies on vertical members to transmit the load which is carried by the arch."
Can there be any replacement for the true arch? I am no civil engineer, nor any kind of architect, but something of pure intuition is telling me there must be some quite possibly as yet unfathomed strength of support that comes by a mystery of Cartesian magic in the geometry of the unbroken contour of a curve. Some kind of grand leverage going on there toward a purpose of uplifting things and holding them up, even over the centuries. Just seems there's something in the fact that the Coliseum is still standing that serves a fair amount of support toward that conclusion.
The false arch of cantilevered steel construction that was thought to be very 'state of the art' for I-35W clearly has not proven to be quite the smart, fresh, with-it idea as its schemers had thought, seeing how it could not even so much as begin to stand up to "the bridge considered the crowning achievement of Minneapolis city engineer Kristoffer Olsen Oustad" as built between the years of 1926 to 1929 to stand the test of time.
http://en.wikipedia.org/wiki/Cedar_Avenue_Bridge_(Minneapolis)
And you have all seen it in the newsfilm, Oustad's bridge, the 10th Avenue Bridge, the "Cedar Avenue" bridge, it's all the same one, standing there yet, strong and serviceable as ever beside the wreckage of the fancy "new" idea.
When I stood there that day on my way home from campus looking out over the river to see the way the builders of that new bridge had seen fit in their hubris to design their construction as to seemingly dwarf (in mere terms of height and breadth) the appearance of the old solution, I was not impressed.
No. I was just not impressed.
I am still not impressed.
--
Mackie
http://whosenose.blogspot.com
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Mackiehttp://whosenose.blogspot.comhttp://doo-dads.blogspot.com/http://www.mackiemesser.zoomshare.com/0.htmlhttp://vignettes-mackie.blogspot.com /
It's my understanding that jets flew into this bridge.
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No. That is what they WANT you to believe, to get you riled up so your will "murder" the "peaceful" "freedom fighters".
Actually, the bridge could NOT have collapsed on its own (cite some lunatic right - or left-wing general). NO BRIDGE has EVEr collapsed on its own in just 5 seconds. For a bridge to come down that fast, it HAD TO HAVE BEEN an inside job.
Witnesses saw people near the bridge removing unexploded charges. It was a CONSPIRACY I tell you! A CONSPIRACY!!!!!
(Did I get the right note of hysteria and lunacy?)

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now Gisse can see the difference in resposibility between mumbling and parrotong of abstarct theories and th e real responsibility of producing real things !!! (:-)
ps therer is a say:
if a doctor makes a mistake one person might die
if a strucural engineer makes a mistake-- a lot of people migh t die....
it seems is not just a loke ...
Y.Porat --------------- Y.Porat ----------
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Did YOU design that bridge?

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On a sunny day (Thu, 2 Aug 2007 02:07:03 -0500) it happened "Mac the Nice"

An example of American design, and America politics putting of repair of the metal fatique parts.
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Probably not an American design problem.
More likely shodddy work by construction unions that are in the pocket of the Democratic Party and/or organized crime.
Or, the money was available to fix the bridge, but it is more important to buy the votes of the "underpriveledged: (aka the lazy) by giving them welfare than to pay actually working people to fix the bridge so that working people could use to bridge to get to work to make the money that politicians would take to buy the votes of those too lazy to work.
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Beauty and pride lose to "development". The soulless won that one.
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Mac the Nice wrote: [snip]

Minneapolis - the city that Head Start forgot. A whole big bunch of White folk who speak literate English without phone-test accents is nobody's Official idea of a good time.
A terrorist attack aimed to cripple the nation would simply take out the building filled with Welfare check printers. Things would then ensue. This is called "leverage." Another example of leverage is having a semi-moron with purported exploding sneakers trigger a $multi-billion/year century of Federal footware inspections at airports.
--
Uncle Al
http://www.mazepath.com/uncleal/
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Mac the Nice wrote:

Roughly two-thirds of all bridges in the US has structural problems.
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Sam Wormley wrote:

You can tell because they look totally shitty and traverse bodies of water like rivers, of all places.
The only safe way to go is *under* the water. The new Atlantic Express Crosser from St. John's, Nfld to Galway, Ireland will be the world's longest subaqueous tunnel when it's finished, and the first major civil works project in history to be designed by a team of drunkards culled from watering holes all over North America and Europe. Experience shows that drunks and children come out unscathed more often in disasters, and authorities reason they should know best how to design for survival.
The Atlantic Express Crosser (AEC '07): "No shitty river-crossing bridge for us, no sir." (Versions of this motto in French and Gaelic are available by request.)
Toll: $300 CDN / 30 per axle, Be sure to use your FasTrak transponder for quicker access during peak hours.
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The structural problem with this one looks to my untutored eye to lie in its design, as built after such a plan as this . . .
http://pghbridges.com/bridgetypes/cant_braced_arch.GIF
You might note that the label for that graphic is styled as a *spandrel-braced cantilever "arch"*, and you see the quotation marks are part of the picture and no irony of mine.
The definition for "cantilever" according to the site from which that image comes is as follows . . .
"A cantilever is a structural member which projects beyond its support and is supported at only one end . . ."
Now look again at the diagram and you'll see exactly what that means, as turning to the right hand tower, and putting yourself into the picture in the boots of the construction crew, you will be affixing one end of the first cantilevered 'arch' member to that pier of the tower, but only after a vertical member has been run up from the pier to deck level, where a diagonal member can then be affixed to receive the yet unsupported end of that girder we first left hanging--or 'cantilevered'.
So now how's that grab you, what we got? We have an arch member that is totally NOT, at this point lending any support to that deck at all but to the contrary is taking its upper end support *from* the deck, or which is to say, from the tower and the vertical member you ran up from it. So this support is not really from the tower, then, but from the upper end of the vertical member being supported, itself only at its lower end by the tower--and from the other direction by the same manner of construction from the preceding span.
From the security camera video . . .

http://www.youtube.com/watch?v=EKLjB_nq76c

It would appear that it's precisely at this point we're zeroing in on where the rupture took place--and why wouldn't it? Consider that while only one end of that cantilevered 'arch' member is receiving support from the tower, the other end in order to get support, must rob the vertical member of its support (from the other lead-in span) at the deck junction.
It would, at first glance appear, absolutely contrary to the function for a true segment of arch, to see that this false arch in no way lends support to the deck. Rather it takes its support from the deck, from the vertical member run up from the tower.
Now look at the next vertical member that runs up from the same point of cantilevered connection to the deck. This is the first vertical member extending from the 'arch' to the deck, ostensibly toward its support. But now we must ask "What support?" As this cantilevered end of the first 'arch' segment is already robbing the deck and vertical tower girder, the preceding span for its support, now it compounds the felony by robbing the deck again from this point, to present a mere *appearance* of support to the deck.
But am I mistaken to suppose there is no supportive arch here? Maybe I'm failing to look at the broader, finished picture. If it can be shown that such an arch could be made to stand alone without support from the deck, then okay I'm wrong. And if I am, then I have failed to see the beauty of a truly grand idea, where it could be said that the deck of the bridge, during construction is forming from this standpoint, a scaffold for the construction of a steel arch. Get the bridge finished, and you could take down the deck and still have the arches fully aloft and holding firm.
Is this right? How are those cantilevered 'arch' segments joined? Welds? Bolts? Are they rigidly attached or are they allowed to give? Are they in essence merely hinged each to the other? If the latter, then once again, how can there really be an arch there, wouldn't it collapse like a collection of rickety sticks after the deck was taken away--or, given the deck, same thing, after a few years of time have worked by normal progress of oxidation and stress to make the weight of that deck unsupportable for those old creaking hinges of joints?
According to the theory as expressed at the Bridge Basics website . . .
http://64.233.169.104/search?q che:SsEonHtJ9XoJ:pghbridges.com/basics.htm+open+spandrel&hl=en&ct=clnk&cd&gl=us
(you may have to refresh to get the graphics)
"Cantilever bridges are constructed using trusses, beams, or girders. Employing the cantilever principles allows structures to achieve spans longer than simple spans of the same superstructure type. They may also include a suspended span which hangs between the ends of opposing cantilever arms."
But, maybe from the standpoint of what happened yesterday, I'm still not buying it, and am just having a real hard time to see any arch there, so that it keeps looking like a case of the Emperor's New Bridge to me.
--
Mackie

"The public have an insatiable curiosity to know everything - except what is
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Compare at the direction of the diagonals again.
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As they always say in Minnesota, to this very day, "Whaddaya mean?" -- Mackie
--

.............................................................
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It's like a structural "Where's Waldo". Look closely at the diagonals in the photo and in the illustration. They aren't the same orientation. If you want me to explain it further than that I'll have to charge you ; ) Maybe Bob's watching this story from his hospital bed and is looking for a diversion....
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Michael Bulatovich wrote good points on the brdge collapse and then said

Looking forward, whenever he is ready...

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<...>

I'm no civil engineer, but a few comments:
The bottom member certainly forms a shallow arch. Intuition if not analysis suggests that such an arch can support a vertical load, but is subject to buckling if thin: hence the diagonal stiffening elements. Whether the structure served more as a shallow arch or a cantilever may be ascribed to the stress system, which is indeterminate even in gross from inspection (the roller bearing were frozen).
More than 500 years after the age of the great cathedrals, it seems civil engineering still contains an element of trial and error. The cathedrals were said to have been built ever taller and more slender, until one or more collapsed. This error was repeated on the Tacoma narrows bridge, and possibly here, where the trend may be taken as cost saving minimalist, but non-redundant, structures. This reflects a more general behavioral syndrome: the diminishing of safety margins until a major accident. In the absense of accidents, extra expensive for safety seems less and less justified: after all, we haven't had any accidents recently!
Failure mode? Could one of the bearing suddenly have become unstuck, the resulting reaction pushing the foot clean off the base? But if the structure was really single point un-failsafe for a significant number of elements, there is an embarrasment of possible initiators, the exact one identified likely to distract from the general cautionary tale.
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