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Iron Alloy Could Create Earthquake-Proof Buildings
separsons writes "Researchers at Japan's Tohoku University designed a new shape memory metal alloy. The super elastic iron alloy can endure serious stretching and still return to its original shape. The scientists say that once optimized, the material could be used in everything from braces to medical stents to earthquake-proof buildings!"
Original article, after following three backlinks: http://uk.reuters.com/article/idUKTRE62I4AE20100319
Here's a page with a bit more detail. These alloys are of similar composition to stainless steel and tend to have very high levels of Nickel and a little Chromium tossed in for good measure. Shape memory alloys work by utilizing a crystal structure phase transition that causes stress in the alloy to re-align which basically is responsible for the shape change.
Sigs are too short to say anything truly profound so read the above post instead.
Earthquake-Resistant!
http://www.physorg.com/news3985.html
Even the beams being put into bridges are concrete because they are stronger and lighter than metal.
Concrete is stronger under compression, but it's so lousy under tension that you put metal into it to take that strain. And how metal is supposed to be stronger than metal I dunno.
And lighter than metal? Not yet. Tell me when you see stadiums with concrete roofs.
Also how you're going to resist an earthquake with only compression I dunno.
Concrete is very good at some things, others not so much.
Personally I don't like formwork buildings. I know they're really common now I know, and you really can do so much with it I see why architects are interested, but right no I just feel like architects haven't figured out how to make appealing buildings with it yet. Right when we finally broke out of the International style with skyscrapers, it feels like formwork has knocked us back a bit.
http://lkml.org/lkml/2005/8/20/95
What is important for construction is the load before the metal begins to yield. If the material yields very early, it doesn't matter how well it snaps back into shape, because it you won't actually be able to build a structure out of the stuff. Just look at some plastics, they are very springy, but try make anything out of the them, and the entire structure starts to flex and sway.
Short version: A material actually needs some stiffness to be practical
In Chile the earthquake was 8.8, and the deaths were about 500 (about half because of the tsunami).
By law, you have to build everything to withstand an 8. I'm not sure if you've been in an earthquake, but I remember perfectly the one in 1985 (was magnitude 8), and it was damned strong. The last one was 6 times bigger.
Anyway, we've been making anti sismic constructions for decades, and you can see the result in the last earthquake. Very few builings falled (most of them old), and low casualties. There have been also 10+ replicas over 6 since the earthquake (also a 7.2).
So, please when you want to be pedantic and tell us "Those places will continue to lose people by the thousands every time a 6+ magnitude earthquake hits", please do your homework first. We usually have a 6+ at least once a year.
Sorry BAG but I have to disagree with you here. Plenty of third world nations have (or potentially) heaps of money, nations like Indonesia have lots of oil, Thailand has massive exports with food and finished products.
The problem is twofold, 1. Skills Shortage. The education systems in the third world do not produce many skilled labourers like Electricians, Fitters, Boilermakers and Architects and certainly not to the standards of the western world. 2. Politics, corruption at all levels as well as lack of standards and standards enforcement means that buildings that are clearly unfit or will fall down as soon as a strong wind blows are built. Going back to the labour situation, in the west the government forces you to use certified architects and electricians (enforcing standards) but they cost double a basic labourer, in the third world a few units of the local currency into the right hands and you can employ barely trained workers for any complex task or pretty much whatever you want.
Imagine for a moment how rich Sierra Leone would be without all that war, a dictators wealth would rival that of Carlos Slim or the sultan of Brunei, a non dictatorial government would have turned it into the Monaco of Africa.
Calling someone a "hater" only means you can not rationally rebut their argument.
How the hell could you use something like flexible concrete that for braces or medical stents? This new alloy isn't /just/ for earthquakes, you know. And that info's right even there in the summary!
Flexible concrete is worse for medical stents or braces than this alloy. Ridiculously worse.
tendons and post stressed tendons and they use them in concrete beams.
Here's a visual representation:
http://www.angryflower.com/atlass.gif
We live, as we dream -- alone....
Vehicle armor especially.
Body armor maybe -- perhaps too heavy.
Could work in a weave though.
"No fear. No envy. No meanness." Liam Clancy
In my opinion, in order:
1. save as many lives as possible and
2. save as much stuff (money) as possible
So, a building structure that is capable to remember its original shape is certainly aimed to meet requirement no.2.
But will hardly meet no.1.
Can you imagine a building that's "flexible" enough to make stairs and elevators useless to people trying to get out of it?
And that'd be just the structure. What about the resulting wall rubble?
Maybe making lower buildings with wider streets in cities could help.
Maybe Computers will never be as intelligent as Humans.
For sure they won't ever become so stupid. [VR-1988]
True; but that one is actually held up by gravity's fear of the Roman Empire. As soon as the laws of nature learn that the Romans are gone, that sucker is coming down...
Chile is not Haiti - at least I don't think it is; I've never been to either one. However, the death toll in Chile was surprisingly low for a magnitude 8.8 earthquake. Sure, older buildings collapsed, just as they do in California and Japan when large earthquakes strike. The death toll in the 1989 Kobe, Japan earthquake was about 5100; more than five times that of the Chilean quake. And Japan is seen as a leader in building earthquake-resistant structures. Obviously, Chile has done something very, very right to keep the death toll so low.
Geology - it's not rocket science; it's rock science
Chile is not Haiti. It is not even California. The building codes are law, and they are enforced. However, there is something to the natural selection thing, but not the way you mean.
Thousands of buildings went through the 8.8 earthquake with little more than a few cracked windows. It looks like total building collapse amounts to 1 building that litterally fell over on its side, and about 100 or so others that failed by design. The ones that failed on a wide scale where 200+ year old adobe houses (mostly one and two story structures). Those adobe structures did survive to some degree because they had never taken a full earthquake. The big ones had always been north or south of the 7th and 8th regions that got hit the hardest by this quake.
The death however was not really caused by the earthquake, but by the tsunami waves that came 3 hours apart. The navy screwed up by lifting the alert too soon, and people started returning to the beach.
My office building (15 floors), took an 8.0 about 200 miles from the epicenter. We lost a couple glass doors when the metal frame flexed, a few cracks, and one broken water pipe on a floor. It was built about 10 years ago.
No one even gets up and leaves the building anymore for anything under a 6.0 around here.
Living in Chile
That is wildly incorrect. Concrete is very usable in compressive members, and is used for a variety of reasons (cost being an extremely important reason), but none of the reasons is because it is stronger than steel. High strength concrete is defined by the American Concrete Institute as having greater than 6000 psi compressive strength. Concrete with 12,000 psi strength is used in structures requiring high performance, and represents a slightly higher strength than was thought possible in 1970. You can get concrete of 19,000 psi strength if you want to pay for it.
Regular dirt cheap time honored 1012 carbon steel had a strength of about 50,000 psi. Concrete is not stronger than that, eh? High strength structural steel is at least 80,000 psi. "Maraging" steel's strength is over 200,000 psi and up to 300,000 psi.
Strength to weight ratio is of course what matters, and here concrete looks considerably better because of its low density. In these terms it's close to so-called high strength structural steel, but doesn't even come close to something like maraging steel, and is outperformed by plain old 6061-T6 aluminum alloy.
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Hey, my hair looks like crap...
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