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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.
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.
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.
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.
Any sufficiently advanced technology is indistinguishable from a rigged demo. -- James Klass
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.
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.
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:
intellectual property law is philosophically incoherent. it is your moral duty to ignore it or sabotage it
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.
Usually "The Science of Bridge Collapse Prevention" is called "The Science of Bridge Construction"
don't cut it off www.mgmbill.org
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.
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) being used to fund the new $522 million baseball stadium. My technique also involves continuing to dash the hopes 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 to deal with the states bridges. But alas, there are voters to buy with that money.
This is about the priorities of the citizens of a staggeringly wealthy nation being focused on everything but the infrastructure.
Lurking at the bottom of the gravity well, getting old
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!
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
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.
A Shadeless room is a brighter room.
For more info, see today's Minneapolis Star Tribune article.
"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.
I had the opportunity to take a course on U.S. Intelligence and National Security from a gentleman who had worked on the Senate Intelligence Committee as a staffer for 10 years during the Cold War, specifically during the Carter and Reagan administrations.
Discussing the politics of funding, he pointed out that it was easy - very, very easy - to get funding for new photo and signals intelligence sattelites, listening equipment, spy planes, and toys. He noted that, yes, some lobbying went on for these projects, but the lobbying isn't what swayed Congress - it was the new and shiny. They could all go home and say to themselves "wow, I put up a massive spy sattelite that can photograph buttons on Russian officers!"
However, when it came to support for this equipment - analysts to look at the data they gathered, technicians to keep them running, maintenance facilities, etc. - they always came up short. In some instances, multi-million dollar pieces of equipment were purchased and deployed only to have the data they gathered analyzed only long after it was too old to be useful, assuming it was ever analyzed at all.
I realize that this post is a bit off topic, but the problem of not supporting what is already there exists all through government. In the case of this bridge, shutting it down would have met with massive protest from all involved. Projects would have caused inconvenience, just as increased personnel staffing creates great cost for the government in many areas. People do the same thing all the time - buy new cars and toys, but never spend the money on maintenance, it all went to the toy. But if we build it or buy it we better be able to keep it in good shape.
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.
Back when I worked for a government office, we were housed in a building that was collapsing. One corner was over a foot lower than the other three and sinking. Huge chunks of bricks were falling off the building. There was a lawsuit over some renovations that were done to the building that allegedly caused the instability. A "feasibility study" was done to determine whether they should spend money to move us all to emergency facilities until a new building was erected, or just take a chance at the building collapsing and having to pay out wrongful death lawsuits. It was determined that "chances are" the building will last and it was financially better to take the chance of hundreds of deaths. (Luckily, the lawsuit was settled pretty quickly and we were moved out within a year and the building was demolished.) I can't help but wonder if the same kind of "feasibility studies" are done on our nations bridges and infrastructure. "Money over lives" is chosen far too often by the powers that be, both governmental and corporate. These new testing methods are just a way to make money off tragedy. We already know what the problem is, we just need to decide that it's "feasible" to fix it.