The Science of Bridge Collapse Prevention 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.'"
Barriers/Lights (Score:2, Insightful)
The bigger problem (Score:5, Insightful)
How about this? (Score:4, Insightful)
Step 2: Start nation bulding OUR COUNTRY
Step 3: No step 3. It doesn't have to be so complicated.
Won't fix apathy and greed (Score:3, Insightful)
In other words:The Science of Bridge Construction (Score:4, Insightful)
Re:Some of the locals seemed to know... (Score:5, Insightful)
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.
So it looks like were all in agreement... (Score:3, Insightful)
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."
Bridge collapse prevention "someday" (Score:3, Insightful)
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:ironic (Score:3, Insightful)
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:The bigger problem (Score:5, Insightful)
Re:ironic (Score:2, Insightful)
Re:Some of the locals seemed to know... (Score:3, Insightful)
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.
Bridge Engineering Isn't What It Used To Be... (Score:2, Insightful)
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.
Re:ironic (Score:4, Insightful)
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:The bigger problem (Score:5, Insightful)
Get elected, then just try raising taxes to pay for something that might happen someday.
Re:Bridge collapse prevention "someday" (Score:3, Insightful)
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:ironic (Score:5, Insightful)
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:The bigger problem (Score:5, Insightful)
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.
Re:Barriers/Lights (Score:5, Insightful)
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.
Re:Barriers/Lights (Score:3, Insightful)
Re:Political (Score:5, Insightful)
benefit analysis (Score:3, Insightful)
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.
Re:How about just using existing know-how... (Score:3, Insightful)
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.
Re:ironic (Score:3, Insightful)
Re:Political (Score:3, Insightful)
It's called a traditional Democrat. They exist. Find one and vote for them, if that's what you prefer.
Re:The bigger problem (Score:2, Insightful)
The superstructure doesn't sound trivial according to this...
Re:The bigger problem (Score:3, Insightful)
1. Its every elected and non-elected public service employee understanding that you NEVER want anything to make the news in a negative way, regardless how correct the information is. This goes for dog-leash laws to fire services. Preventing this from happening is almost their number 1 job.
2. Regardless of what your perception is, there are some serious employees at any government. How many professional civil engineers, with their oaths and rings and ethics, do you think are looking at the roads and bridges at the local government? How much money is being spent? Its so easy to say "this should have been prevented" and lay it on lazy bureaucratic government workers. Maybe we should have some more rules/paperwork and levels of government so this never happens again?