Don -- Minneapolis road bridge collapse

Well, I am guessing here, but one of the TV stations in twin cities area put up some "before" photos that appeared to show MASSIVE corrosion where the bridge support structure attached to a pier. I mean an AMAZING hunk of orange rust-colored stuff that should have been clearly visible a thousand feet away. I've never seen that much rust on a major highway bridge before, only on abandoned railway trestles and such. Now, the pic wasn't real clear, but I am fairly sure what I was seeing there was SERIOUS corrosion damage.

Allowing a structure like that to deteriorate to such a level without doing anything about it is criminal negligence!

I will wait for the investigators to prove me wrong, but I think they may well see the same things when they start looking at it.

Jon

Reply to
Jon Elson
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Indeed. I was thinking of some of the places here in So. Cal, like where the 60/10/5 all join up, with a follow up on the 710/105 (entry to the LA port..lots of truck and tanker traffic). The bad guys could effectively shut down So. Cal for a month or more, plus release all sorts of nasty toxic clouds, no matter which way the wind is blowing.

The freeways are the arteries and veins of So. Cal...and the West. Small handful of tangos, loot and schoot a NG armory...the rest is a bad dream.

Calfornia..is not Texas, unfortunately.

There is destructive...and mentally debilitating to an entire population.

I can think of far more destruction..but its hard to shut down So. Cal by blowing up a facility etc.

And in my sceanario..the bad guys could simply wake up, do their prayers, and go out every day and repeat, with little risk. Look how long and how much terror those two idjits back east caused by shooting onsies at gas stations from the trunk of a car.

As a general once said..we will be more than happy to help them get their introduction to their 72 virgins...

Reply to
Gunner

Whats easier than simply pulling up on an overpass and shooting up the lanes below? All it takes ia one or two drivers getting shot to cause a massive traffic accident, with lots of spreading fires and pools of gasoline setting all sorts of things on fire, machine gunning those running away, trapped by the freeway fences and concrete walls and tying up a main artery of traffic for days. Total time on sceane would be only a couple minutes and you simply drive off.

You arent going to get the same easy killing zone, massive casualties, and free escape in a movie theater or stadium, nor will you tie up a city for weeks.

Run to where? Here in LA..most freeways are strongly fenced, or are in concrete ditches. Folks climing the fences are easy targets.

Shrug

Gunner

Reply to
Gunner

Tell that to the dead in the World Trade Center.

Gunner

Reply to
Gunner

It's not like anyone would vote to spend the money on roads and bridges. Not money on the old ones. Not before this hit the news, anyway. When it's not the flavor of the week, the pressure will be off, as far as upgrading or maintaining the rest will go, too.

No matter how the governments spend the tax bucks, it at least starts doing laps through the economy.

That war is keeping a lot of money circulating, some (much, I suspect) of which is paying wages for a pile of Americans that might otherwise be doing without work.

Lots of people making the connection between the war in the sandboxes, and where else the money "might" have been spent. I think, were it not for the war, the money would have gone elswhere, rather than being pounded into infrastructure. Infrastructure is not a "sexy" way to get ones picture in the paper, or get re-elected, no matter where you are.

My sympathies go out to those injured, and to the families of those lost in this wreck.

I think it is a small wonder that the numbers appear to be so small, considering the time of day, and the traffic volume. Reports I see online suggest that the toll may be in the area of 30 lives, once the tally is done. I hope it to be less.

Hindsight is usually pretty clear. The infrastructure decline has been happening steadilly for many years, under the watchful eye of political parties of every stripe, and likely will decline further, as more people are willing to pay less of their salary for what they believe to be a right to have all these conveiniences.

I hope for everyones sake, that there are enough guys around, able to inspect the thousands of "deficient" bridges out there, and that they will make sound decisions.

It will be noteworthy, seeing what the findings of the investigation are, and seeing if there really was anything that could reasonably been done to forecast this tragedy or prevent it entirely. Reasonably, of course, is going to be a closely debated line, isn't it.

Respectfully

Trevor Jones

Reply to
Trevor Jones

Talk has it that resonance from a jackhammer from the construction crew did the bridge in....

Reply to
kbeitz

I heard there were 12 handheld jackhammers and one mounted on a skidsteer on site plus milling machines. But didn't Mythbusters that to be plausible but not likely?

Reply to
Up North

Don, That was precisely my theory, that the long line of cars, all stopping and starting, waiting to get into some lot, Stop, start. Once they started a motion on the bridge, they would have unconciencly reinforced it. Fell a slight motion, and hit the gas or brakes. The long line of cars all starting and stopping, the acceleration/ braking wavefront would travel the length of the bridege, over and over.

I wonder how many bridges get a "wavefront" on them due to a long line of cars, in stop and sop traffic?

Reply to
Half-Nutz

My sources say that the stop and go was before the bridge, once you hit the bridge it started to speed up to moderate speeds. And only 4 of the

8 lanes were > >
Reply to
RoyJ

Bridges aside, traffic above some level of density does exhibit some fluid flow characteristics. That was shown in studies during the 60's and 70's. You can sometimes see downstream artifacts of an event (like an accident) an hour and many miles "downstream", like clusters or concentrations of traffic between rarefactions.

Reply to
Don Foreman

I guess I'm just the nerd type cause I've seen a lot of neglected bridges. I've also taken many baths under bridges on road trips. The worst that I saw was a bridge north of East Boston if memory serves. It was stop and go traffic and the thick steel riveted columns where rusted through both sides so that you could throw a foot ball through the hole and into the salt water.

Reply to
Sunworshipper

You have to look at the finite element analysis of the failure and the conditions of the structural members that failed to be sure. And most of that really big stuff isn't welded, it's riveted.

They had only two main truss arches for an 8-lane-wide bridge and two main pier-point bearing members at each support point, plus the approach spans also relied on the main span staying up and vice versa

- absolutely no structural redundancy.

If a main member on one of the two main trusses of the main span or an approach span lets go, it's all coming down - and you have the potential for huge loss of life. If they end up under a dozen dead after that mess during rush hour, it's only because they had two lanes closed each side for deck repaving work and that limited the exposure.

Where if there were four or five arches in parallel deliberately spreading the load to four or five separate support points at each of the piers, and the approach spans were supported separately so they could fail independently, one failure would probably not be totally catastrophic - even though you could see the deck sink or tilt precariously and might even lose a few cars if it's one of the outside trusses that fails.

But if it exists, structural redundancy should keep the majority of the span up long enough to stop traffic and evacuate.

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Reply to
Bruce L. Bergman

Interesting.

Interesting. What you say means that a person with a pound of C4, could easily take the bridge down if he knew exactly where to place the charge.

i
Reply to
Ignoramus2331

There's no future to taking the discussion in that direction. Any competent engineer or chemist knows a dozen ways to create mayhem on a vast scale.

Reply to
Jim Stewart

I was not.

I agree that it is a good mental exercise, I will practice. That will hopefully teach me what to stay away from when possible.

i
Reply to
Ignoramus2331

I've been on the Mackinaw Bridge during the Labor Day walk and experienced it "bucking". People were actually losing their footing and falling down because the bridge was swaying. I guessed maybe 6-8 inches side-to-side at the time. This was out in the middle area. The expansion joints were making a nice bang-bang-bang... all the time it was swaying. The two times I remember this were on dead calm mornings. No wind to speak of, even out in the middle of the bridge.

When the walk first starts out there will be solid people across two road lanes (the north bound or east side) for the entire length of the bridge. The other side is reduce to a single lane of bumper-to-bumper traffic in both directions.

A bit unnerving, but it hasn't fallen down yet :)

Reply to
Leon Fisk

Did they find a similar bridge and take a construction crew out to try to bring it down?

Or just "think" it unlikely?

Reply to
cavelamb himself

With cell phones, mp3 players and other distractions that is a posibility. I used to be an advid roadie bicyclist but the thought of how many people now on the road are playing with their electronics makes we more likely to ride a mtb on single track where it is safer.

Answering an earlier question, between Fife Lake and Kalkaska east of US131.

Wes

Reply to
Wes

Aaahhhh. Paranoia, what a lovely thing. You are well trained.

Reply to
The Patriot

Shoot.

Try that stunt around here and find out just how many Texans (Men AND Women!) actually do carry guns. And Big Bad ones at that.

Or how much we would absolutely LOVE to have a legitimate target to retaliate on. Lot of pent up anger to release, you know?

But not bad as a mental exercise. A bit involved, but not bad.

I can think of several other approaches that don't involve as much coordinating - or as many people - or risk to the attackers - or even need guns.

And be an order or magnitude or two more destructive.

You see, our systems - our way of life - was never intended to deal with this kind of thing.

Who would want to intentionally destroy paradise.

Oh! Well, yah, maybe those guys - who don't HAVE one yet.

I guess I should feel sorry for them - but I don't any more.

Reply to
cavelamb himself

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