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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.
Modern construction techniques and materials are actually really good. Except for the occasional airliner or two crashing into them, our buildings are able to withstand tremendous strain. These days, most new buildings in the modern world are built with these techniques and materials. Flexible yet firm. Light yet strong. We've come a long way in this respect.
But we also have the money to build these things. Take a look at some recent tragedies caused by earthquakes. Bam, Chile, etc. These aren't places that have especially tall buildings. In fact, most of their buildings are slapped together walls with heavy roofs. When the ground starts shaking, these things are death traps.
So this new technology is great, but don't expect to see it saving lives in the Third World. Those places will continue to lose people by the thousands every time a 6+ magnitude earthquake hits. They just don't have the money to build correctly.
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.
Omori said the super-elastic iron alloy may also be used for buildings in earthquake prone areas. "This material can be used for buildings in earthquake zones. The buildings are deformed by earthquake, but super elastic alloy can return the building to its original structure," he added.
There's no much detail but somehow I don't think that will happen unless he's also invented a 'super-elastic' concrete ..
By the prophet Ayn Rand in her prophecy Atlas Shrugged! The glorious Rearden Metal has come to save us all!!
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
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.
You know, a regular-type stadium for football or basketball or whatever. Never heard of an aquarium being called a marine life stadium before.
If I were building a building designed to hold brine and thus a salt-tinged atmosphere, I'd be tempted to use concrete too. The aquarium in Monterey for example is entirely made of concrete.
But every sporting-type stadium I know uses a roof made of steel or fabric. Why? Because it's light. The only weight it has to hold up it is own, so the less weight the roof can have, the less material you need. And steel uses a lot less material than concrete for these things. Even if you had concrete spans (possible although difficult), it'd be corrugated steel actually forming the roof to save weight. The fabric roofs are even lighter, although in that case the air inside is actually supporting the roof, not the roof structure itself.
http://lkml.org/lkml/2005/8/20/95
tendons and post stressed tendons and they use them in concrete beams.
http://www.physorg.com/news3985.html Even the beams being put into bridges are concrete because they are stronger and lighter than metal.
Correction: Even the beams being put into bridges are bendable concrete because they are stronger and lighter than metal.
More on that Bendable concrete: "Essentially, the fibers create many microcracks with a very specific width, rather than a few very large cracks (as in conventional concrete.) This allows ECC to deform without catastrophic failure" http://en.wikipedia.org/wiki/Bendable_concrete
But before Bendable concrete this is how things were done: There are 3 kinds of forces, Tension, Compression, and Torsion (twisting motion).
Concrete is not "stronger" than steel, it is simply better in compression than steel (it can support more weight). If concrete is in tension beyond the limit, it will break (suddenly and without warning). Concrete is reinforced with steel because the steel complements it. Steel shows signs of fatigue before it breaks when over its limit. Also with changing temperatures, both steel and concrete expand and contract at similar ratios.
The tensioners are steel. So again, it's metal doing the work here, it's not going to be stronger than metal, it is metal.
Concrete is great for stacking stuff up. It can carry a lot of weight. But it isn't light and it is useless under tension, so metal (almost always steel) does that work for it.
http://lkml.org/lkml/2005/8/20/95
This has already been done
http://en.wikipedia.org/wiki/Fiber_reinforced_concrete
Dampers have been used for ages to improve building resistance to earthquake and wind motion. It is much cheaper to add/improve a damper system that will counter the effect of the earthquake on the building than to build it/rebuild it with earthquake resistant material.
Furthermore these "advanced materials" are more sensitive to fatigue, something not likely to be seen in a building that is designed with rigid steel beams.
Seems to be a solution in search of a problem.
See http://en.wikipedia.org/wiki/Tuned_mass_damper
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]
Anything like the metal they pulled from that ship that crashed in Roswell?
I first read the subject line as, "Irony Could Create Earthquake-Proof Buildings"
http://world.kbs.co.kr/english/news/news_Ec_detail.htm?No=71276
if your pants fit well, it's not only because of the pants
Let's see a terrorist attack THAT. "OH GOD IT'S GONNA CRASH!!!" Boi-oi-oi-oing... "Oh."
the building shaking, the building will flail about in the air tossing the inhabitants around like a washing machine. There has to be some stability in the structure to allow people to safely exit.
I'm sure this approach will protect the buildings, but falling objects and/or people are one of the main causes of injury in an earthquake. I'm not sure this is better.
It's already been done - I saw it on tv once. Transparent aluminium.
How about putting this metal in cars? Never have a totaled vehicle again!
"Earthquake proof"? Is that like "unsinkable"? And who among us hasn't broken the "unbreakable" comb, huh?
i seriously doubt you can fool mother earth during a 7 or 8 into believing that your building is flexible enough to straighten up 100%. once a slinky gets bent, it never works the same and it's practically impossible to fix it.
Remember kids, if you're not paying for the service, YOU ARE THE PRODUCT THAT IS BEING SOLD.
The best FRC has an Ultimate Tensile Strength of only 6.4 MPa, the tensile strength of structural steel is ~400 MPa.
Give up.
So the metal can bend, but goes back to its original shape. So the building can spring back to its original shape after the walls flop down and squish you. Yup, that's good for the building.
"Earthquake proof"? They used to make the same claim for another iron alloy: Steel
Correction: Even the beams being put into bridges are bendable concrete because they are stronger and lighter than metal.
ECC - Engineered Cementicious Composite - is NOT used in bridges. Your standard I bulb beams are prestressed concrete. It has high strength concrete in it (compression typically > 5500psi) but it is almost never fiber reinforced.
In fact for that matter the "newer" concrete technologies, ECC, RCC, SCC, to name a few are not widely used in industry. Some projects use them but they are not common.
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.
http://en.wikipedia.org/wiki/Pengrowth_Saddledome
http://www.canada.com/calgaryherald/news/story.html?id=bb367c51-527e-4abc-b61a-39821fa3f0f9
"Working with British structural engineer Jan Bobrowski, whose firm still lists the Saddledome on its website, the design team came up with the concept of a roof made of precast concrete panels supported by a net of cables. Think of it as a giant tennis racket, a grid of cables, and on this net you drop these concrete panels,"
Vehicle armor especially.
Can we start with fenders?
My God, it's Full of Source!
OUTSIDE_IP=$(dig +short my.ip @outsideip.net)
This won't be noticeably better at dissipating energy rapidly through the structure. You need to generate massive damage to the structure to dissipate the energy of impact from a bullet in order to make good armor. Phase change alloys bend too easily to do this.
The next challenge for materials scientists will be an intermediate elasticity material for walls. The ability of the frame to flex several percent under the force of an earthquake is a good thing, full stop. But then the walls will need to be flexible enough not to be torn off the flexible frame, yet firm enough not to deform, and thereby shatter, every single window. Granted, broken windows will kill and seriously injure fewer people than falling buildings, but engineers will want to minimize window breakage as well. It sounds like a fun problem to try to solve.
"I can't imagine how things could get any worse!" (some guy) "That could just be failure of imaginatioÂn on your p
Awesome, I can fabricate me a T1000 for those days my boss is is being a tool.
Unlike the Saddledome which is larger, but is really held together by steel cables with concrete panels just basically creating an enclosure, not the load bearing structure.
I found out about so many interesting structures by spouting off incorrectly like a bonehead!
http://lkml.org/lkml/2005/8/20/95
You'll have to deal with the auto body repair lobby first, but then again you'll have the car insurance lobby in your court. Let the name calling begin.
"No fear. No envy. No meanness." Liam Clancy
Cool. Thanks for that, AC. It is popular to deride Slashdot, but the truth is I often learn stuff around here. Perhaps because I don't know much to begin with.
"No fear. No envy. No meanness." Liam Clancy