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The Science of Bridge Collapse Prevention
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.'"
Would this system also have a feature to alert the local road authority, or in a worst case scenario close the bridge?
If your neighbours roof is flying past your window, you know it's cyclone season.
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.
The Schwartz space ain't from Spaceballs.
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.
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.
Usually "The Science of Bridge Collapse Prevention" is called "The Science of Bridge Construction"
don't cut it off www.mgmbill.org
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.
AccountKiller
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."
The Schwartz space ain't from Spaceballs.
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.
You see? You see? Your stupid minds! Stupid! Stupid!
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
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.
"Even if you're on the right track, you'll get run over if you just sit there" - Will Rogers
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.
AccountKiller
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.
Banjo - The more I know about Windoze, the more I love *nix
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?
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.
"We can categorically state we have not released man-eating badgers into the area." - UK military spokesman, July 2007
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.
"She's a scientist and a lesbian. She's not going to let it slide." Orphan Black
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.
Slapdash. If you calculate that your empire lasts forever the most economic way to build is to engineer structures that last forever.
You mean like someone who would say "we need to raise taxes on, let's say, the wealthy (because they can afford it more readily) to fund infrastructure improvements across the country. Besides fixing all the aging infrastructure from the time when public works was still consider part of a great society, it will add hundreds of thousands of American jobs."
It's called a traditional Democrat. They exist. Find one and vote for them, if that's what you prefer.
It doesn't hurt to be nice.