Beta
×

Welcome to the Slashdot Beta site -- learn more here. Use the link in the footer or click here to return to the Classic version of Slashdot.

Thank you!

Before you choose to head back to the Classic look of the site, we'd appreciate it if you share your thoughts on the Beta; your feedback is what drives our ongoing development.

Beta is different and we value you taking the time to try it out. Please take a look at the changes we've made in Beta and  learn more about it. Thanks for reading, and for making the site better!

The Science of Bridge Collapse Prevention

Zonk posted about 7 years ago | from the so-far-we-have-not-found-the-science dept.

Science 276

toddatcw writes "In the wake of the Minneapolis Interstate 35W bridge collapse this week, Computerworld investigates ongoing research which could someday help to prevent future disasters. Acoustic emissions detection systems, which listen for the sounds of metal snapping on structures, are already sold and fitted. Likewise, a new generation of detector systems that monitor for tilting of bridge columns and piers are being designed, prototyped, and researched. 'Sound waves move more efficiently through solid objects than through air, making any sounds easier to listen out for, Tamutus said. "It's not amazing. It's simple. Doctors use stethoscopes all the time. If you put your ear on a train track, you can hear a train approaching from far away... The Sensor Highway II systems, which are portable and can be moved from bridge to bridge as needed, usually cost between $20,000 to several hundred thousand dollars each. Typically, evaluations take between one day and a week.'"

cancel ×

276 comments

Sorry! There are no comments related to the filter you selected.

Barriers/Lights (2, Insightful)

Archades54 (925582) | about 7 years ago | (#20109527)

Would this system also have a feature to alert the local road authority, or in a worst case scenario close the bridge?

Re:Barriers/Lights (3, Informative)

choongiri (840652) | about 7 years ago | (#20109579)

Meanwhile, engineering research projects, including one at the University of Missouri-Columbia, were already under way long before this week's bridge collapse to advance the science of bridge monitoring. At the school, work is being done on a large-scale sensor system that would be fastened to several concrete bridge piers below a span to alert officials about even the slightest tilting or swaying of critical piers supporting a bridge.

Re:Barriers/Lights (1)

canuck57 (662392) | about 7 years ago | (#20110507)

alert officials about even the slightest tilting or swaying of critical piers supporting a bridge.

So was not this bridge already warned to politicians that it needed work? Do we need a 5000 DB whistle to make them wake up? The writing was on the wall.

We will as a human race either evolve to vote past voting for hype turkey ass kissing politicians or someday they will foobar us all real big. Fortunately it was less than 30. Could have been worse. Happens in Canada, or shall I say Quebec too: http://en.wikipedia.org/wiki/Quebec_Bridge [wikipedia.org]

Re:Barriers/Lights (2, Insightful)

donaldm (919619) | about 7 years ago | (#20110783)

Yes you can get sensors that will detect the slightest tilting or swaying of critical piers but the problem is that many bridges are designed to tilt and sway to a certain tolerance otherwise a ridged bridge would just crack under a small tremor or ever a surge of water. You would have to have sensors like this on all bridges and take into account the design tolerances of the bridge. You could do this cheaply in a country that has only a few bridges but when you have thousands of major bridges this is going to get expensive and you also have to take into account false alarms.

Re:Barriers/Lights (3, Funny)

igny (716218) | about 7 years ago | (#20110023)

In the worst case scenario, the bridge closes itself.

Re:Barriers/Lights (1)

donaldm (919619) | about 7 years ago | (#20110745)

Unfortunately in the worst case scenario the bridge did close itself but it did it in a manner that caused people on the bridge to die. People who were lucky not to be on the bridge at the time of the collapse were safe although I would be quite sure they would be shocked. Even if the bridge had gates and they operated it would not help the people who were already on the bridge.

Re:Barriers/Lights (1)

canuck57 (662392) | about 7 years ago | (#20110405)

Would this system also have a feature to alert the local road authority, or in a worst case scenario close the bridge?

It was already there, but no one was listening. How do you solve that?

Re:Barriers/Lights (4, Insightful)

donaldm (919619) | about 7 years ago | (#20110681)

Taking into account all the factors that can cause a disaster is just about impossible. While it is possible to design something that is nearly disaster proof it can't be done with 100% confidence, because there are things that can occur that can be outside of the original design plan. Two simple examples are designing for a category 4 hurricane and then getting hit with a category 6 or designing for a richtor 5 earthquake and then getting hit with a richtor 7 earthquake.

All that can be done is to have a flexible disaster prevention (eg. periodic bridge checks which actually were done) and a rescue program in place which from what I read about was quite good although to some who lost friends and relatives maybe not good enough. I would leave that to the investigation committee to comment on this.

The problem with any disaster is it normally happens with little or no warning and sometimes so quickly people just cannot get out of the way. The question of "it could have been prevented" is rather mute after it has happened.

Easiest solution (1, Funny)

Anonymous Coward | about 7 years ago | (#20109549)

instead of steel, harness the power of Cory Doctorow's ego.

Re:Easiest solution (1)

thatskinnyguy (1129515) | about 7 years ago | (#20110619)

If you were a PhD, you know you would be a total dick about it too. I know I would!

Political (1)

sugarmotor (621907) | about 7 years ago | (#20109551)

Is it not the easiest just to elect people who take care of things?

At least from what I heared there are a lot of bridges in similar shape, but there's not much done about it.

-- Stephan

Re:Political (2, Funny)

Kagura (843695) | about 7 years ago | (#20109615)

Well, it didn't take long before a government contractor came up with a fool-proof way to secure government funds. Er, I mean, to prevent future incidents...

Look at me, I'm cynical tonight. :)

Re:Political (4, Insightful)

ktappe (747125) | about 7 years ago | (#20110797)

Is it not the easiest just to elect people who take care of things?
If history is any judge, no, it apparently is not easy at all for the voting public to do that.

The bigger problem (5, Insightful)

weak* (1137369) | about 7 years ago | (#20109563)

It was known well before the collapse that the bridge was in need of repairs. It seems that no public employee, elected or not, understands that prevention is better than reaction. New techniques to detect a heightened probability of failure are useful only if someone acts on the information once it is available.

Re:The bigger problem (5, Informative)

Anonymous Coward | about 7 years ago | (#20109789)

It was rated 'structurally deficient' [msn.com] :

The Minneapolis bridge's deck, or driving surface, was rated in "fair condition." The superstructure was in "poor condition," and the substructure in "satisfactory condition."
It looks like the 'satisfactory' substructure is what failed. Repairs to the driving surface and the trivial superstructure were ongoing. There was no indication from inspections that the substructure was in need of immediate repairs.

The classification of structurally deficient means that either the surface, the superstructure, or the substructure was rated poor. In this case it was the superstructure which for this particular bridge did not provide support. A little bit of repairs to the superstructure and this bridge would have been cleared of its structurally deficient rating.

Re:The bigger problem (4, Insightful)

GIL_Dude (850471) | about 7 years ago | (#20109993)

Get elected, then just try raising taxes to pay for something that might happen someday. Or, try to re-allocate funds from some bleeding heart program and see how far you get. People in general are not willing to fund repairs for things that might happen. It reminds me somehow of the little guy "Short Round" in Indiana Jones and the Temple of Doom jumping up and down on the footbridge yelling "strong bridge, see, strong bridge" just before starting to fall through the bridge. Obviously this is NOT FUNNY that this happened, but it just shows how people always want to think everything is fine right up until the time that it isn't fine.

Re:The bigger problem (4, Insightful)

JonathanR (852748) | about 7 years ago | (#20110287)

)
Get elected, then just try raising taxes to pay for something that might happen someday.
Terrorism?

Re:The bigger problem (1)

ScentCone (795499) | about 7 years ago | (#20110883)

Terrorism?

Which... actually HAS happened. Just like bridge collapses have happened. The difference is that there isn't so much malice involved in structural failure by way of aging infrastructure (as opposed to, say, flying airplanes into buildings or driving truck bombs up to otherwise perfectly fine structures).

Bridges don't routinely pronouce their desire to alter your culture and spread Bridgelam by way of killing themselves. I think what we really need here is a sense of specifically which of the 70,000 bridges that have been labeled "deficient" are "actually ready to fall down."

Re:The bigger problem (1)

plunge (27239) | about 7 years ago | (#20110293)

Americans like feeling heroic. Preventing tragedy isn't very telegenic or interesting. But letting things to go shit makes for damn good tv!

Re:The bigger problem (0)

Anonymous Coward | about 7 years ago | (#20110509)

It was known well before the collapse that the bridge was in need of repairs. It seems that no public employee, elected or not, understands that prevention is better than reaction.
The problem here is that "in need of repairs" is not at all the same as "about to collapse", no matter what you may hear in the media.

Anyway, it's hilarious to hear software geeks of all people talking about reliability.

If bridges crashed as often as computers do, we'd probably all be caulking up our cars and floating them to the other side whenever we wanted to cross a river.

Re:The bigger problem (2, Informative)

flyingfsck (986395) | about 7 years ago | (#20110669)

Well, people were actually busy doing repairs when the bridge collapsed. It is possible that the hammering of the repair activities contributed to or hastened the collapse.

Re:The bigger problem (5, Insightful)

penix1 (722987) | about 7 years ago | (#20110677)

It seems that no public employee, elected or not, understands that prevention is better than reaction.


No it isn't...

This may seem callous and cold in the wake of this incident but in fact it is cheaper (hence "better") for the state to react sometimes than to mitigate a hazard. It is simple economics. The federal cost share is 75% federal, 25% state. In catastrophic events, that split drops to 90 / 10, or at the discretion of Congress, 100% federal (Katrina is 100% federal). If the hazard you are attempting to mitigate would cost more than if it fails, then it is cheaper to let it fail. Of course, you run the risk to life and property when you do this so it is a huge gamble.

States are cash strapped with the thousands of "unfunded mandates" the federal government places on them. Everybody want services but don't want to pay for them in higher taxes. Then you get pandering politicians running on "lower taxes" campaigns further reducing a states ability to operate properly. It is a wonder it took this long for something to happen.

Wireless Sensor Networks (2, Interesting)

dominious (1077089) | about 7 years ago | (#20109585)

Put some wireless sensor nodes across the bridge and sense for unusual vibrations between the intersections. That's what Wireless Sensor Networks is all about. When there is a crack the vibrations will cause a signal to be sent out.

Re:Wireless Sensor Networks (1, Interesting)

Anonymous Coward | about 7 years ago | (#20110309)

Los Alamos National Laboratory has been developing this technology.
See http://abcnews.go.com/Technology/story?id=3441742 [go.com]
"The idea is to put arrays of sensors on structures, such as bridges, and look for the changes of patterns of signals coming out of those sensors that would give an indication of damage forming and if it is propagating," said Chuck Farrar, a civil engineer at the lab.

How about this? (4, Insightful)

rolfwind (528248) | about 7 years ago | (#20109597)

Step 1: Stop nation building OTHER COUNTRIES
Step 2: Start nation bulding OUR COUNTRY
Step 3: No step 3. It doesn't have to be so complicated.

Re:How about this? (0, Offtopic)

zussal (1058116) | about 7 years ago | (#20109727)

Why do we ship all of our good produce out of the country just to import lower quality stuff?

Re:How about this? (0)

Anonymous Coward | about 7 years ago | (#20109889)

if you think we're nation building Iraq, you haven't been paying attention

Rafter Man: "Well, at least he died for a good cause,"
Animal Mother: "Which cause was that?"
Rafter Man: "Democracy...?"
Animal Mother: "Flush out your head gear, New Guy. You think we waste gooks for democracy? Don't kid yourself; this is a slaughter, and if I'm gonna get my balls shot off for a word I get to pick my own word and my word is poontang."

Re:How about this? (1)

mikerubin (449692) | about 7 years ago | (#20109907)

This should not be modded flamebait - I agree wholeheartedly !

Its one thing to provide charity to others, but is this the cost/reward to us for doing that?

No, this is the result of neglect and short-sightedness.

Re:How about this? (1)

canuck57 (662392) | about 7 years ago | (#20110431)

Makes a lot of sense. Think, instead of saving the middle east, let them knock each other off. Let them buy the bombs for profit. Turn it to bridge reconstruction. No, I am not kidding, I though this parents post was accurate and sane. Why spend billions on Neanderthals when you can build at home.

Re:How about this? (0)

Anonymous Coward | about 7 years ago | (#20110519)

> Step 1: Stop nation building OTHER COUNTRIES
>Step 2: Start nation bulding OUR COUNTRY
>Step 3: No step 3. It doesn't have to be so complicated.

Why do you hate America? Can't you see we're building bridges over there, so we don't have to build bridges over here!

(CAPTCHA: "soviet". Oh, the fucking irony.)

Technology is not the solution to this problem (0)

Anonymous Coward | about 7 years ago | (#20109603)

We need congress to step in and criminalize gravity.

Possibly a war on gravity may be needed.

P.S. This is not a money problem. We are shipping shiploads of cash to faraway lands and paying millionare trust fund babies not to farm. Maybe we can put those funds someplace more useful.

Re:Technology is not the solution to this problem (0)

Anonymous Coward | about 7 years ago | (#20109659)

Maybe we can put those funds someplace more useful.
Hate to be cynical, but fat chance.

Re:Technology is not the solution to this problem (0)

Anonymous Coward | about 7 years ago | (#20109771)

We need congress to step in and criminalize gravity.
Gravity is just a theory. As such it (and all science) is nothing more than an attack on God. We don't float off into space because it is God's will.

Re:Technology is not the solution to this problem (1)

Belacgod (1103921) | about 7 years ago | (#20110037)

So when do we sue God for collapsing the bridge?

Re:Technology is not the solution to this problem (1)

CastrTroy (595695) | about 7 years ago | (#20110349)

You really should check out The Man Who Sued God [imdb.com] . Basic premise is man loses his boat/home is struck by lightning, and the insurance company won't pay out because it is an "act of God". So he decides to sue God. The logic is that the church (God's representatives on earth), argue that God didn't destroy his boat, then the insurance company should have to pay him. Either way he's entitled to money from someone. Really funny movie that really shows the flawed logic insurance companies use to get out of paying. I really have to watch this again sometime.

Re:Technology is not the solution to this problem (1)

Belacgod (1103921) | about 7 years ago | (#20110367)

What if they claimed not to be responsible because it was the work of the devil?

Or if he tried a shotgun lawsuit against the Catholics, Baptists, Unitarians, Muslims, etc? In that case none of the defendants would risk trying to get out of the case, because whoever's god was responsible is the true religion.

Re:Technology is not the solution to this problem (0)

Anonymous Coward | about 7 years ago | (#20110215)

Congratulations! You've won the troll of the week award! What are you going to do now?

I'm agoin' to Disney World!

Some of the locals seemed to know... (5, Interesting)

Thorrablot (590170) | about 7 years ago | (#20109609)

I'm a Twin Cities resident (local name for Minneapolis/St. Paul), and have taken this bridge hundreds of times, as well as biked along trails on the riverbanks below it. It was never an attractive bridge, but certainly showed no obvious signs of problems. I was shocked to learn that a good friend of mine was told by a structural engineer two weeks ago that he "always avoids driving on that bridge during rush hour" - apparently the engineer had already read/heard something that we're just finding out.

This smacks of criminal negligence - complete catastrophic failure in 4 seconds could not have been an undetectable condition.

Re:Some of the locals seemed to know... (4, Informative)

Paktu (1103861) | about 7 years ago | (#20109663)

There's conflicting reports about it. The Feds inspected it a few years ago and said it was in immediate need of repair, but the state sent in people who claimed it would be viable until 2020. While it might appear that the state just didn't want to spend money, keep in mind that Minnesota has the third lowest percentage of structurally deficient bridges [statemaster.com] , so it's not like there were other major priorities that were sucking up funding.

Re:Some of the locals seemed to know... (1)

Thorrablot (590170) | about 7 years ago | (#20109859)

There's conflicting reports about it. The Feds inspected it a few years ago and said it was in immediate need of repair, but the state sent in people who claimed it would be viable until 2020. While it might appear that the state just didn't want to spend money, keep in mind that Minnesota has the third lowest percentage of structurally deficient bridges [statemaster.com] , so it's not like there were other major priorities that were sucking up funding.

Thanks for the statemaster link - good research link.

I have heard about these conflicts, and have an incredibly hard time understanding why:
  1. If a federal inspection says it needs repair, how does a state inspection override this?
  2. Why should the state be responsible for the safety and inspection of a federal bridge?
  3. What oversight is there to insure that the state doesn't "pay for what they want to hear", and that they make sure they get a contractor who saves them from expensive maintenance?

Something is rotten (aside from the beams) about the whole situation. Why would a random engineer happen to know this bridge was unsafe and avoid driving on it? Why wouldn't the legislature listen to the more cautious reports from a "higher authority", instead of the less cautious ones (money?)

And the really terrifying question is of course, what's to keep this from happening again?

Re:Some of the locals seemed to know... (4, Informative)

moosesocks (264553) | about 7 years ago | (#20110161)

Likewise, you're not exactly going to be able to attract funding to fix or replace the bridge if you're going around telling everybody that everything's just peachy.

Personally, I sort of doubt that this could have been prevented. It's one of those one-in-a-billion sort of odds that unfortunately caught up with us...

I'm more than a bit irked at the media for taking the "structurally deficient" term, and plastering it all over the news without a very clear understanding of what it means. There's no cause for a panic or a rucus -- our bridges are no more dangerous today than they were last week. Hell, we don't even know what caused the bridge to collapse, and ordering all sorts of emergency inspections (which has been done in many many states so far) is pointless considering that the bridge that collapsed was previously deemed to be safe on multiple occasions.

Of course, other recent incidents such as the con edison steam explosion in NYC reek of criminal negligence.

Re:Some of the locals seemed to know... (0, Flamebait)

zussal (1058116) | about 7 years ago | (#20109705)

I didn't have anything to watch on TV that night though. So it wasn't all bad.

Re:Some of the locals seemed to know... (4, Insightful)

Vellmont (569020) | about 7 years ago | (#20109731)


This smacks of criminal negligence - complete catastrophic failure in 4 seconds could not have been an undetectable condition.

You have way to much confidence in science and technology. I think it's certainly possible that the inspections done didn't detect the problem with the bridge. Science isn't perfect, and there's always assumptions and things no one knows.

Re:Some of the locals seemed to know... (1)

Thorrablot (590170) | about 7 years ago | (#20109981)


This smacks of criminal negligence - complete catastrophic failure in 4 seconds could not have been an undetectable condition.

You have way to much confidence in science and technology. I think it's certainly possible that the inspections done didn't detect the problem with the bridge. Science isn't perfect, and there's always assumptions and things no one knows.

I do have high confidence in civil and structural engineering. This bridge was built in 1967, and is a style that would not be built today, due to an intrinsic lack of redundancy in the support structure. One span breaking was known as all that was needed to cause the bridge to collapse.

This was a known limitation of the architecture. Given this fact, I *do* believe that proper engineering to frequently inspect, and monitor the bridge (including real-time strain gauges) would have detected the problem. I also doubt that the proper engineering was done - and I suspect that this was not due to lack of recommendations, but more likely due to "fiscally conservative" minded legislature that was ultimately only penny-wise.

Re:Some of the locals seemed to know... (2, Insightful)

Vellmont (569020) | about 7 years ago | (#20110081)


I also doubt that the proper engineering was done - and I suspect that this was not due to lack of recommendations, but more likely due to "fiscally conservative" minded legislature that was ultimately only penny-wise.

The bridge was inspected in 2005 and 2006, so there was quite a lot of inspection of the bridge occouring. If they had reason to believe the bridge was going to collapse, it would have been shut down right away. The major bridges across the country are inspected every 2 years.

Anyway, it's waay to early to start ruling anything in or out as to what went wrong. My point isn't to say "it can't be politics in play", but to try to put some balance into a situation where we know very little about what caused the failure.

I do agree in general though that not enough funding is being put into the countries infra-structure. Whether that's a direct cause of this bridge collapse I don't know.

Re:Some of the locals seemed to know... (0)

Anonymous Coward | about 7 years ago | (#20110281)

You have no idea how well steel truss bridges are understood. Truss bridges in general are very strong, well built versions expected to last hundreds of years should civilization end tomorrow. They're also labor intensive to build. Expensive. Steel as a construction material is exceptionally well understood, and what's not well understood is being investigated in very long term creep experiments. Steel isn't like aluminum where you can't trust it. Given proper composition, installation and care (corrosion etc) it's dependable. It doesn't have to be replaced (just in case) in the same way Aluminium does. It's a great cheap, strong, tough, forgiving, durable material who's only real defficency is it's density.

Someone didn't do their job. They were either incompetent or they lied. The price is lives. And now in stead of rehabilitated or a scheduled replacement, there's the catastrophic failure, attendant destruction, and unscheduled replacement which is vastly more expensive. Were politicians not listening to science, or were the those practicing engineering derelict? Well, we'll probably find out. But those involved should probably end up breaking rocks if not swinging from a rope.

Re:Some of the locals seemed to know... (2, Interesting)

Jimithing DMB (29796) | about 7 years ago | (#20110877)

I also doubt that the proper engineering was done - and I suspect that this was not due to lack of recommendations, but more likely due to "fiscally conservative" minded legislature that was ultimately only penny-wise.

Ahh, here we go. It's the GOPs fault. If only we'd spent federal money used for the Iraq war to fix this bridge. This was the first comment on Kos about this tragedy and it was echoed verbatim by several reporters in the mainstream media. I don't mean they just had the same thought, I mean they used the same damn words.

Then there's the other one.. if only they'd instituted a 5 cent/gallon gas tax that was proposed. That's a more simple "pay as you go" (e.g. tax and spend) approach instead of the "creative approach" those damn Republicans in the state were trying to come up with to finance road work. That was courtesy of the Minneapolis Star.

Fact is that Minnesota (like most states) has a budget surplus and could have paid for the bridge repair without raising taxes. Perhaps they'd have had to spend less on that new stadium or less on that new art gallery. So what? Can we maybe all agree that fixing the roads ought to be higher on the priority list than doling out money for a privately owned stadium?

All I can figure is that several people probably decided that it was unlikely that the bridge was going to collapse. They had conflicting reports from engineers, some saying it would in say 5-10 years, others giving it more like 20 so long as some repairs were done. So what did they do? They paid for the repairs figuring that repairing the existing structure to get a few more years out of it was a responsible choice vs. building an entirely new bridge.

It's disingenuous to suggest as others have that they paid off the state inspector to paint a more rosy picture after the federal inspector gave a pretty bleak one. It was in nobody's interest to get a more rosy picture since the state still had to pay for the repairs which ultimately, with the benefit of hindsight, were shown not to work.

In the end, I think what we're going to see here is that it wasn't really a case of wanton disregard for safety but rather a reasonable and responsible choice (a calculated risk) that happened to go horribly wrong. It's easy to say now that they should have paid for a new bridge rather than paid to repair the existing one, but that's only now with hindsight.

The good news is that the people of Minnesota really banded together and helped each other out of the tragedy. One of the boys on the school bus apparently took it upon himself to open the door and lead the people out. People on the ground stood by the bus on a crumbling bridge and helped the passengers out. Divers are working in absolutely insane conditions to find the dead so they can give the family a definite answer. That's the real story here. There is still some good in this world, even in the face of tragedy.

Re:Some of the locals seemed to know... (1)

MtViewGuy (197597) | about 7 years ago | (#20109869)

Two things I immediately noticed that made me openly wonder why this bridge was so vulnerable:

1) The spindly structure makes it apparent that the whole thing will come down even with one minor structural stress problem.

2) The surprisingly small size of the bridge supports.

I personally expect the replacement bridge to be a writ large size version of 10th Avenue Bridge nearby with its thick, concrete structures.

Re:Some of the locals seemed to know... (4, Informative)

Thorrablot (590170) | about 7 years ago | (#20110035)

Yes - there's a good writeup here [wikipedia.org] already.

The bridge is a truss arch bridge [wikipedia.org] built in 1967. The design doesn't interfere with river traffic (well, up until two days ago anyways) - but I did hear an interview with a Berkeley professor describe how such bridges are no longer built due to their lack of redundancy in case of span failure.

Ultrasonic testing isn't new. (0)

Anonymous Coward | about 7 years ago | (#20109617)

http://en.wikipedia.org/wiki/Nondestructive_testin g [wikipedia.org]

We still don't know why the bridge in question came down. The structure was non-redundant. That means that if any part of the structure fails, the whole thing fails. In that light, the sudden failure of a structural member would bring the bridge down quickly and there wouldn't be sufficient warning to save lives. For example, an off-center load might overload an otherwise safe member.

None of this is to say that bridges shouldn't be instrumented. Such instrumentation would show ongoing changes in the condition of bridges and could lead to corrective maintenance. Until now, most inspections have been visual and that has been mostly successful. The collapse of a bridge/overpass in Quebec last year came about because the builder didn't do his job properly and the inspectors weren't properly trained. Even with the most rigorous testing, cheap lazy politicians will still put off spending on maintenane items because they don't get many votes. The best way to insure the safety of our crumbling infrastructure is to hold the decision makers personally liable for their decisions.

Won't fix apathy and greed (3, Insightful)

ChromeAeonium (1026952) | about 7 years ago | (#20109619)

As the old phrase goes, an ounce of prevention is worth a pound of cure. The technology's nice and all, but I'd saw the trick is getting people to look into this sort of thing, and take action, beforehand. I say this because in my area there was an old bridge that many people used regularly, however, it was a well known fact that it was deteriorating. The city, however, didn't want to spend the money to fix it, and it was years before anything was done (despite the fancy new road nobody wanted or needed that was built just minutes away). That bridge could have possibly collapsed, and everyone knew it. This new technology might make detection easier, but as long as the almighty buck is king, no amount of technology can compensate for human nature.

Re:Won't fix apathy and greed (1)

Detritus (11846) | about 7 years ago | (#20109913)

We could take an idea from Hammurabi, and drop several hundred tons of concrete and steel on the heads of the government officials responsible for the safety of the bridge.

No one expected the Levies to break. (0, Flamebait)

infonography (566403) | about 7 years ago | (#20110219)

Lets just lay the blame on the knucklehead that got us into this disaster of depleted local resources and the rest of his gang of cronies. His little war has cost devastated the resources and personnel needed to deal with this. this is symptomatic of Katrina and the Iraq War. They were too busy with their wet dreams to pay attention to wet people and cities.

The Dems may be effective but nobody can match a Republican for Naked Greed.

See Delay, Stevens, Foley, Rupert Murdoch, Ad nauseam

The science of commas (1)

noidentity (188756) | about 7 years ago | (#20109633)

Acoustic emissions detection systems, which listen for the sounds of metal snapping on structures, are already are being sold and fitted.

Bridges (1)

polygamous coward (1127507) | about 7 years ago | (#20109639)

Ever hear of "collapse of the infrastructure"? How graphic.

How about just using existing know-how... (1)

the_skywise (189793) | about 7 years ago | (#20109647)

Like building structural redundancy into the bridge to begin with?

Re:How about just using existing know-how... (5, Interesting)

Paktu (1103861) | about 7 years ago | (#20109711)

While it's easy to ask "why didn't they just make it redundant?", there are reasons behind these decisions. Please take a look at this link: http://www.visi.com/~jweeks/bridges/pages/ms16.htm l [visi.com]

There's a lot of good info there, but here are the cliff notes:

A University of Minnesota Civil Engineer in a report to MN-DOT recently noted that this bridge is considered to be a non-redundant structure. That is, if any one member fails, the entire bridge can collapse. A key factor is that there are only four pylons holding up the arch. Any damage to any one pylon would be catastrophic. The textbook example of a non-redundant bridge is the Silver Bridge over the Ohio River. It failed shortly before Christmas in 1967 resulting in 46 deaths. A single piece of hardware failed due to a tiny manufacturing defect. But that piece was non-redundant, and the entire bridge collapsed into the icy river. Today, bridge engineers design bridges so that any single piece of the bridge can fail without causing the entire bridge to collapse. It is tragic that the I-35W bridge was built a few years too early to benefit from that lesson.

Hmmm, 1967 (1)

calidoscope (312571) | about 7 years ago | (#20110299)

IIRC, the I-35 bridge was built in 1967, so the designers/builders weren't as painfully aware of the importance of redundancy as after the collapse of the Silver Bridge.


A similar thing happened in California wrt the 1971 Sylmar earthquake. Several bridges of the newly completed I-5 came down, the cause was found to be lack of hoop strength in the re-bar inside the column. Columns built after that used helically wound rebar to keep the column intact under seismic loading. The need for retrofitting was driven home during the 1989 Loma Prieta quake and was further sped up after the 1994 Northridge quake when the reinforced bridges survived and the ones waiting for reinforcement collapsed.

Re:How about just using existing know-how... (1)

dhanson865 (1134161) | about 7 years ago | (#20110521)

Lets see the Titanic sank in 1912. Is that not enough of a lead time for engineers to figure out that redundancy and quality of manufacture are key components to public safety? Why wait 55 more years for the Silver Bridge collapse to say that bridges should be built with enough over design aka fudge factor to survive a manufacturing defect?

Re:How about just using existing know-how... (2, Interesting)

calidoscope (312571) | about 7 years ago | (#20110693)

The problem with the Silver Bridge was not so much underdesign, but the lack of redundancy in the eyebars used in the suspension members. Most suspension bridges use bundles of steel wires, if one wire breaks there are enough redundant wires to take up the load. In the case of the Silver Bridge, when one of the pins holding two of the eyebars broke, there was no redundant member to take up the load. What made things worse was that the towers holding the suspension members were on rockers, so they fell down when the eyebars failed.


Something similar may have happened with the I-35W bridge, a lack of redundancy led to the bridge to collapse as a result of a single piece failing.


By the way, most aircraft are required to maintain structural integrity after the failure of a single structural element such as a wing spar.

Re:How about just using existing know-how... (2, Insightful)

vux984 (928602) | about 7 years ago | (#20110917)

Lets see the Titanic sank in 1912.

Seriously? The Titanic? You realize the Titanic was considered unsinkable precisely BECAUSE it had redundancy (double bottom), other 'state of the art' technology, and went beyond the standard for lifeboats. (Even though there were not enough, yes, it was more than the standards called for.)

The ONLY lesson that could be learned from the titanic is that NOTHING is invincible/unsinkable/indestructible.

ironic (2, Informative)

circletimessquare (444983) | about 7 years ago | (#20109709)

there's a rant i read a few days ago from a what seems to be a bitter old time engineer who says that ancient styles of bridge design fare better than more modern ones because of redundancy: if something fails, the damage is localized, rather than the whole bridge going because of just one of many of its elements. he points to something called "value engineering"- aided by computer analysis, that is the source of this kind of bad nonredundant bridge design that was the I35W bridge

what's ironic is that modern technology has therefore made bridges less safe, by empowering those from the middle of the last century who wished to save money by losing less materials, at the expense of safety by sacrificing redundancy. just read what he says, saying it better than me [nytimes.com] :

14.August 2nd, 2007 1:39 am

Compare the collapsed steel truss bridge with the reinforced concrete arches of the intact bridge in the background of some of the photographs. The concrete bridge consists of inherent stable arches, a design which has stood the test of time since the Roman Empire. Even if one arch of this bridge had fallen, the remaining arches would have remained intact and loss of life and injury would have been limited to the failed section.

Compare this with the more recent bridge, composed of steel trusses which held up a concrete deck. The entire 1000 foot long section was tied together structurally to save money. It had no tolerance for partial failure. If one section failed, the entire section would go down. This more modern bridge was ugly as well as a poor design. This bridge was designed by modern engineers who have no sense of beauty and think they can calculate every decision on the basis of cost/benefit. They practice a destructive type of design called value engineering - taking out the expensive stuff if it's redundant or optional.

We don't yet know which piece of the structure failed, but it may have been a small one - such as rusted steel, steel which looked OK on the surface but had deteriorated in its carrying capacity, perhaps in tension. The connection between concrete rebar and the supporting steel space frame.

This poor design based primarily on cost considerations has been required all over this country in countless projects for the past 50 years.

One section of the old San Francisco-Oakland Bay Bridge failed in the 1989 Loma Prieta Earthquake because there wasn't enough "give" for the shaking due to the quake. Two lives were lost - one by a woman who tried to drive her car across the gap and who would have survived had she waited for help. However, the rest of the bridge remained and will be used until this fall when it is destroyed after the new bridge opens.

The new San Francisco-Oakland bridge which is replacing the old bridge has the same basic flaw as the bridge which collapsed in Minneapolis today: If any one piece failes, the entire bridge will fail catastrophically! The new Bay Bridge is designed to look elegant and be a landmark - but it has no redundancy in an area with severe earthquakes. It too was designed by modern engineers. It will be a disaster waiting to happen, just like the World Trade Center and the Route 35 Minneapolis Bridge, and the New Orleans levies. America no longer has the leading structural engineers of the world designing its infrastructure. How many of them owe their jobs to our failing political system?

It is ironic that the lack of redundancy in any structure also makes it inherently more susceptible to terrorism - witness the collapse in the World Trade Center.

America is in bad shape, and we seem to be addressing our problems in a piecemeal and ultimately stupid way.

-- Posted by MJ

Re:ironic (2, Insightful)

Ron Bennett (14590) | about 7 years ago | (#20109905)

Some may be interpret his comment about NY WTC 1 & 2 as over the top, but he's right on ... they too were an example "value engineering", to borrow a phrase from above, while having redundency for their outside shells, did NOT for the floor slabs themselves; each floor was designed to around 3x expected load, but that's of little to no help in a "pancaking" scenerio in a tower that had well over 100 floors...

Also, some of the other "value" decisions made during WTC 1 & 2 construction are laughable by today's standards, such as using drywall instead of concrete in various parts of the core structure. Contrast that with the Empire state building, which despite being somewhat smaller, contains over double the steel, considerable amounts of concrete, substantial fire-proofing, and are built with a box frame contruction, which is highly redundent.

Ron

Re:ironic (2, Insightful)

dwhite21787 (166571) | about 7 years ago | (#20110055)

from what I recall, the WTC was well engineered. The heat retardant on the structural steel was applied badly, and the beyond-tolerance damage of the jumbo jets managed to take out the planned redundancy. I wouldn't put the WTC in this category.

Re:ironic (4, Insightful)

Alastor187 (593341) | about 7 years ago | (#20110189)

Are sure that was written by an engineer?

He says look at the WTC, it collapsed because of the lack of redundancy.

What?

Seriously, the building was hit by 150,000 lb aircraft carrying 20,000 gallons of flammable liquid. It was obviously never designed to withstand that kind of structural complication.

However, for a minute lets say someone had enough foresight to add "resistance to impact from commercial aircraft" into the structural requirements. Why stop there? What about earthquakes, hurricanes, tornados, tsunamis, or meteorites?

Where do you draw line? How much cost can you tolerate?

It is not engineering that is overly concerned with cost to benefit ratios, that responsibility falls on management and/or accounting. If engineering comes up with two designs for a bridge, where one is under budget and lacks redundancy and the other is over budget and but incorporates redundancy, it is management or the customer that must decide what is most important.

Now some people may say that engineering has an ethical responsibility to build the best product, which may be true. But how does one do that, by quitting their job every time that don't get their way? Or by building the better a better product with the lesser budget, that is working for free?

While I agree that modern engineering has a lot less design tolerance. I think this is thanks to a better understanding of physics as well as better tools. So it is now possible to safely design bridge with a poor failure mode because we 'better' understand what drives the failure (I am not saying that poor failure modes are better).

In this case I think the inspection process is more suspect than actual design. I think everyone would agree that the design had areas of concern. But no design is perfect and all bridges will eventually fail. That is why they are inspected on regular bases. How is it that this bridge was inspected in the last few year and no critical issues were found? Doesn't that mean that a better inspection process is needed?

Re:ironic (2, Interesting)

ucblockhead (63650) | about 7 years ago | (#20110451)

One big reason Roman bridges lasted so long is that the Romans had no clue how to build a bridge that was strong "enough". Because they were ignorant of the math and engineering required, they instead just built as strong as possible, damn the cost. This was, of course, much, much stronger than strong enough to last a few decades. We, with our modern engineering, can build things that are strong "enough", and thus, don't last near as long and are generally weaker. But we save lots of money.

Until someone miscalculates.

Re:ironic (2, Insightful)

quax (19371) | about 7 years ago | (#20110923)

Slapdash. If you calculate that your empire lasts forever the most economic way to build is to engineer structures that last forever.

Re:ironic (4, Insightful)

macaddict (91085) | about 7 years ago | (#20110647)

disaster waiting to happen, just like the World Trade Center

A disaster? WTF do you have to do to be considered a success for this guy?

A fuel-laden commercial jet slams into a 110 story building (x2) and a little less than 3,000 people died.

The buildings could have collapsed immediately and killed, what, about 20,000 people? But both stood long enough (56 minutes and 102 minutes) to evacuate most of the occupants. Sounds like a pretty damn successful building design to me.

Re:ironic (0)

Anonymous Coward | about 7 years ago | (#20110851)

I seem to recall hearing that an aircraft collision was considered in the design process of the WTC towers. They were well aware of the incident where the B-25 flew into the Empire State Building.

IIRC they considered the effects of the largest airliner of the day, the Boeing 707 I think, colliding with the tower.

I agree with you that all in all they did pretty well considering the buildings temporarily withstood the impacts of two aircraft that were larger, heavier, and carrying more fuel than the aircraft they considered while designing the towers.

In other words:The Science of Bridge Construction (3, Insightful)

viking80 (697716) | about 7 years ago | (#20109723)

Usually "The Science of Bridge Collapse Prevention" is called "The Science of Bridge Construction"

they got the check? (1)

Ep0xi (1093943) | about 7 years ago | (#20109763)

i thought that the engineers of bridges were still trying to make cash that check the goverment gave them

How about building bridges like the romans (1, Interesting)

Anonymous Coward | about 7 years ago | (#20109773)

that last 2000 years or more?
Little maintenance.
No sensors.
No inspections.
No reports.

Re:How about building bridges like the romans (1)

wkitchen (581276) | about 7 years ago | (#20110919)

And how many heavily loaded trucks drive across those each day?

Isn't it too late? (0)

Anonymous Coward | about 7 years ago | (#20109795)

By the time you can hear the little beams cracking, isn't it too late? Isn't the roadway in a free fall within an instant?

So it looks like were all in agreement... (3, Insightful)

weak* (1137369) | about 7 years ago | (#20109801)

...that someone we're paying with our tax dollars either fucked up or didn't care. Now what? Can we simply vote for better people? Of course not: history demonstrates conclusively that these better people don't exist, don't want the job, or go unnoticed (largely because the general public doesn't have the time or the means or the interest to assess the competence of prospective officials). So what do we do to put qualified people into positions responsible for our welfare, and hold them accountable once they're there?

It's a hard question, so I think I'll just ignore it, in light of the sad truth that a month from now, no one (who doesn't have a personal connection to the tragedy) will care. To hell with "doomed to repeat it."

Re:So it looks like were all in agreement... (1)

blitz487 (606553) | about 7 years ago | (#20110817)

I look forward to our health care being managed by this same process!

My technique (4, Interesting)

TopSpin (753) | about 7 years ago | (#20109807)

I have a method of Minnesota infrastructure maintenance that can assure sound bridges. My technique involves billing the Twins owner for the $392 million of government revenue (collected via a sale tax hike [wcco.com] ) being used to fund the new $522 million baseball stadium. My technique also involves continuing to dash the hopes [startribune.com] of Minnesota football fans for a new government funded $0.5 billion football stadium. Instead, let the team owners rely on sports geek revenue to fund their stadiums, and misappropriate the tax revenue into infrastructure.

On the other hand, perhaps it isn't necessary to piss off all the Minnesota sports geeks (read: voters) and instead utilize the $2 billion dollar state surplus [publicradio.org] to deal with the states bridges. But alas, there are voters to buy [ncsl.org] with that money.

This is about the priorities of the citizens of a staggeringly wealthy nation being focused on everything but the infrastructure.

Re:My technique (1)

couchslug (175151) | about 7 years ago | (#20110051)

What a terrible idea!
Look at the benefits New Orleans got by attracting the Saints instead of spending that money on tacky flood control...

Re:My technique (1)

TopSpin (753) | about 7 years ago | (#20110819)

Look at the benefits New Orleans got by attracting the Saints instead of spending that money on tacky flood control...
Peace Brother. I hear you.

Bridge collapse prevention "someday" (2, Insightful)

Junior J. Junior III (192702) | about 7 years ago | (#20109833)

What a joke. We've been building bridges for the whole of recorded history, and some of them have stood for much of that time. We have the capability and have had it for centuries if not millenia to build a bridge that doesn't fall. We just have to pay attention and maintain what we build. It's not THAT hard.

Maybe if we stop worrying about falsely exaggerated threats like terrorism and manufactured problems like the war on in Iraq, we'll have more than adequate resources to build a really damn good infrastructure, and then things like the bridge collapse in Minneapolis and the steam main explosion in NYC wouldn't ever happen.

Re:Bridge collapse prevention "someday" (2, Insightful)

petermgreen (876956) | about 7 years ago | (#20110323)

We've been building bridges for the whole of recorded history, and some of them have stood for much of that time.
and i'm sure many of them haven't

sure if you build a stone arch accross a narrow vally in an area with no sismic problems then it will stay up for a very long time, especially if the area is too dry for much plant life. However it will be very expensive for the ammount of utility it gives.

but of course we want more, we want our longest bridges longer, we want all our bridges able to stand being packed with heavy lorries we want to bridge accross fault lines and so on and of course like with everything we want it as cheaply as possible. The result is much narrower safety margins and use of new materials and construction styles which may suffer unanticipated problems. There is also the human nature to ignore problems until they become critical.

Re:Bridge collapse prevention "someday" (2, Interesting)

MichaelSmith (789609) | about 7 years ago | (#20110385)

We just have to pay attention and maintain what we build. It's not THAT hard.

I used to work for the state highway authority, working on traffic signals. When I was there the entire bridge department were made redundant and replaced by contractors. No matter how much you document these things, you still need continuity from one generation to the next. The old guys have to be around to tell the young guys to look out for this and that, or it may cause problems.

But it is cheaper to outsource.

Haha -- Minnesota, land of Ultra Liberals (-1, Troll)

Anonymous Coward | about 7 years ago | (#20109851)

I guess when all you have to offer the world is a degree in "Women's Studies" and Afro "Culture", your bridges don't have a Chinaman's chance in hell.

Here's an easy way (1)

/dev/trash (182850) | about 7 years ago | (#20109969)

Stop building goddamn sports stadiums and zoo exhibits and concentrate on what's important.

Whats the difference? (0)

Anonymous Coward | about 7 years ago | (#20110089)

What is the difference between an American freeway bridge and a lasagna?

Nothing.

Bridge Engineering Isn't What It Used To Be... (2, Insightful)

BanjoBob (686644) | about 7 years ago | (#20110159)

Maybe we should go back to stone and mortar bridges. Today's bridges in America don't last very long and they never meet the roadway without a bump or a dip. Many are obsolete or too small by the time they are even completed. Modern engineering doesn't stand a chance to the builders of yesterday.

Take a look at the famed Rialto Bridge in Venice, Italy. This bridge was built almost 500 years ago and still stands even after numerous earthquakes in the region.

Then there is the stone bridge in the Czech Republic, the Charles Bridge that is a short 650 years old. Listed in the "Most Beautiful Bridges of the World", it was built in 1357 to replace an earlier bridge that was destroyed. It's still functioning fine.

Lets trek on over to Aberdeen, Scotland and their Brig o Balgownie bridge dating from 1286 and still in use today.

Even in the United States, we have 165 year old High Bridge in New York and Steel Bridge in Oregon that are both in use and good condition today. Although not stone bridges, they were built to last.

Now, we have a 40 year old bridge collapsing yesterday and a 35 year old bridge being completely replaced here. The Woodman bridge has a huge bump in it that will almost certainly remove your air-dam if you go the posted 40 MPH speed limit. A small bridge in Denver had to be replaced about 10 years ago and it was only about 10 years old. It seems that we are no longer capable of building a bridge that will last.

One must ask why with all the advances in science and engineering during the past 5 centuries why we can't build a decent bridge today? Why can't we have a street and bridge meet so the pavement is the same level? Why don't we build bridges like they used to? Even aquaducts built 15 centuries ago are still supplying water to Istanbul.

Obviously, when it's cheaper to build a bridge like the one in Minneapolis-St. Paul that only lasts 40 years and only kills a few people during its lifetime, but will cost hundreds of millions of dollars to cleanup, law suits and to replace, one must ask where are the priorities? Why not build a bridge to last centuries instead of decades? Wouldn't it be cheaper in the long run?

We just don't make them like we used to. Somewhere along the line, the need to have something last has been lost. Are our bridges disposable commodities like the cars we drive across them? It does make one wonder.

please (0)

Anonymous Coward | about 7 years ago | (#20110209)

+ this if you can

I just wanted to say thanks for the dept. name. (0)

Anonymous Coward | about 7 years ago | (#20110213)

Because Soul Coughing is fundamentally beautiful.

A collapsing bridge is terrifying (1)

Christoph (17845) | about 7 years ago | (#20110221)

A massive bridge collapsing underneath you is terrifying, e.g. a source of terror. We could close the thousands of bridges in the US that, like the 35W bridge, are rated "structurally deficient", in the name of preventing "another 8-1". This might help expedite funding to rehab these bridges, and fighting the "terror" of unsafe bridges would fit with our current national priorities.

Boring (1)

smchris (464899) | about 7 years ago | (#20110297)

What do they have about the _SOCIAL_ science of politicians who say, "Well, it probably won't fall down on _my_ watch so I'm going to be a 'tax-cutter'"?

Yes, a little testy. From the Cities and watched it from first rumor until dark on the MythTV box. Burned a DVD of the lot. Used to work at U of M and commuted from near South Minneapolis. Remember the bridge well.

Dumb bitch of the Transportation Commissioner was on the news 10 minutes ago. I just looooved her line about, "Don't any of you accuse me of wanting this bridge to collapse!" Hey, babe. I'd never accuse her of that. That would take THINKING and intention. I'm accusing her of knee-jerk dumber-than-crap Republican sucking of all money out of infrastructure for tax cuts to the rich. And, yes, I can imagine she sincerely _didn't_ want the bridge to collapse because she was "_HOPING_" ("praying"?) it wouldn't so she wouldn't get caught with her pants down where everyone could see how WORTHLESS her Neocon "management" was.

I'm just waiting to see whether they sell off the right to the Saudis to build a toll bridge over the river now that a convenient and handsome business opportunity has "presented itself". GOD, I HATE REPUBLICANS THIS WEEK.

Re:Boring (0)

Anonymous Coward | about 7 years ago | (#20110401)

Maybe you should worry about the pork barrel spending that goes on, getting term limits for our elected officials, removing their pensions, and getting rid of campaign contributions by corporations, instead of having knee-jerk reactions and buying into all the political garbage on both sides.

Myth and Rice Crispies (1)

PingPongBoy (303994) | about 7 years ago | (#20110359)

If you put your ear on a train track, you can hear a train approaching from far away

Has anyone done this before? The bumper sticker on a train reads If you can hear me, your head will be cut off.

Feel a rail on a track. Long after a train has passed, the track is still hot. I put my ear to the track, but could not hear the train through the rail. This was a rail that has its segments bolted for high speed trains. However, I did hear the train in the air, ear not on rail. The train was a high speed train with a loud diesel. As a wheel passes over the gap between two segments of track, there is a click that is loud enough to be a thunk, but the train would have to be too close before that sound is transmitted through the rail loud enough to be heard over the engine, which is audible when the train is over 2000 metres away and out of sight.

Trying to listen for the snap, crackle, pop of a bridge may be futile. A traffic bridge would have all kinds of noise from vehicles and surrounding industry. The bridge in Minneapolis crosses a river and a railway. Not a quiet scene.

We could use this in Montreal (1)

BeerGood (561775) | about 7 years ago | (#20110469)

Minneapolis? Heck bridges have been falling down like dominos in Montreal. Why do you think we drive so fast? We want to get by the overpass as quickly as possible!

How acoustics helped parking garage problem (1)

JavaManJim (946878) | about 7 years ago | (#20110581)

This is a parking garage story.

About five years ago, a chunk of cement about the size of a football fell on a buddy's car in the parking garage. At that time, the garage was a few years old.

Engineers were called in and placed acoustic monitors all over the place on many of the beams. Then drove vehicles over them on a couple of weekends.

Evidently acoustics found anomalies. They determined that the interior cabling was insufficient.

After a couple of different fix attempts engineers decided on the following.

Added two reinforcing high tension cables to the outside of each approximately 60 foot beam in that huge parking garage. This involved drilling two six inch holes at the ends of each beam. A heavy wall pipe was put into each hole. Them flanges were welded to the ends of each pipe. Then cabling was strung on each side of the beam. The beams were curved so at the apex of the curve were placed hangers that the cabling went over. This way the cabling did not go directly to the other side but roughly followed the beam's curve.

This was at headquarters of a national clothing retailer JCP.

Thanks,
Jim

Bureaucracy will kill the efforts (1)

bogaboga (793279) | about 7 years ago | (#20110597)

While there seems to be ways to "listen" and detect potential problems with bridges, I doubt that the bureaucracy of government will ever make the remedies work.

Coupled with my government's incompetence, bigotry and history of wasting money (read Iraq), it will surely be a wonder if this setup ever works. God help us!

the sky is falling again... (0, Troll)

llZENll (545605) | about 7 years ago | (#20110627)

Jesus people, I guess it's time to waste a billion dollars making sure all of our bridges our safe, or the terrorists have won. Honestly though, it is sad that innocent people died, but come on, what is the death toll, like 5-20. Everyones attention, money, and time would be much better spent fighting more important problems, like cancer and heart disease. Anything more than having a few engineers look into some old bridges they built is overkill. Are there not laws requiring continual safety reviews of major public structures already?

Say what??? (1)

E++99 (880734) | about 7 years ago | (#20110715)

Acoustic emissions detection systems, which listen for the sounds of metal snapping on structures are already are being sold and fitted.

Metal snapping? Why not just listen for motorists screaming? I assume these actually listen for some kind of metal stress sound, rather than actual failure? No, I didn't read TFA, so feel free to ignore me.

The data was already there (2, Informative)

michaelmalak (91262) | about 7 years ago | (#20110763)

From yesteday's New York Post [nypost.com] :

A 2001 evaluation of the bridge, prepared by the University of Minnesota, reported that there were preliminary signs of fatigue on the steel truss section under the roadway, but no cracking.

The report said there was no need for the Minnesota Transportation Department to replace the bridge because of fatigue cracking.

But a May 2006 report by the department noted that inspectors saw fatigue cracks and bending of girders along the span's approaches.

I.e., in 2001 they barely passed it because they said, "at least there's no cracking." In 2006, they saw cracking but kept the bridge open anyway. At minimum, they should have closed it to heavy truck traffic, scrapped the idea of doing heavy construction (repaving) on the bridge, and started construction of a replacement immediately.

For more info, see today's Minneapolis Star Tribune article [startribune.com] .

Irrelevant by 2010 (1)

jgarra23 (1109651) | about 7 years ago | (#20110779)

In 2010 we'll have flying cars and those skateboards from BTTF Part 2 so we'll just fly over these places that need bridges.

benefit analysis (2, Insightful)

fermion (181285) | about 7 years ago | (#20110831)

What all this misses is there are armies of accountants wieghing risks of an accident against costs to prevent the accident. The system is not perfect, but it is the one we have, and the one we will likely continue to have. Most of the technology in this article is not new. It simply requires a higher budget. Certainly, we could spend money to better detect fatique, but in a worl or limited resouces, is the best use of money to reduce risk?

Perhaps if this accident killed hundreds of people, and resulted in a settlement of tens of billion of dollars, then the landscape might shift. Or, if like automobile manufacturers of past, we find that the accountants are making fundamental compromises of safety merely because the cost of a human life is less than the cost of implementing the features.

About the only thing that does not fall under this risk analysis is the military. This is why they can get away with spending 100 billion dollars a year with only a discrediting italian letter to substantiate the claim, a letter not even endorsed by the US government, but by the british. Otherwise we have to use the imperfect system of where to spend our money and where not to. I don't suppose that we are going to see an increase in taxes, or the removal of the new corporate welfare incorporated a few years ago, or a reduction in say in money spent on standardized test for kids. i think we can have anything we want if it is really worth sacrificing.

Load More Comments
Slashdot Login

Need an Account?

Forgot your password?

Submission Text Formatting Tips

We support a small subset of HTML, namely these tags:

  • b
  • i
  • p
  • br
  • a
  • ol
  • ul
  • li
  • dl
  • dt
  • dd
  • em
  • strong
  • tt
  • blockquote
  • div
  • quote
  • ecode

"ecode" can be used for code snippets, for example:

<ecode>    while(1) { do_something(); } </ecode>