Slashdot Mirror
Japan Creates Earthquake-Proof Levitating House System
An anonymous reader writes "Japanese company Air Danshin Systems Inc. has developed an innovative system that levitates houses in the in the event of an earthquake to protect them from structural damage. When an earthquake hits, a sensor responds within one second by activating a compressor, which forces an incredible amount of air under the home, pushing the structure up and apart from its foundation. The air pressure can keep the home levitating up to 3cm from the shaking foundation below. In the wake of last year's Fukushima disaster the company is set to install the levitation system in 88 houses across Japan."
The house is not firmly attached to the foundations except by this glorified airbag.
Don't they also get typhoons there?
I eagerly await the Japanese sequel to the Wizard of Oz.......
Donte Alistair Anderson Roberts - hi son!
Karma: Chameleon
http://www.youtube.com/watch?feature=player_embedded&v=NubZJA4c_Rw
Seems like it would require an awful lot of force just to float a small house. An interesting idea that might be useful in other areas. But I don't see how this could catch on long term for things like apartment buildings or skyscrapers.
And let's not forget that it wasn't so much the earthquake that devastated Japan. But it was the wall of water that mowed down everything in its path.
Depends... housing ain't cheap in Japan, and getting a new one may be hellishly expensive when compared to keeping your old one from coming apart.
Also, what's easier, saving the house (and everything in it), or rebuilding from scratch? It's not just the cost of the house you have to keep in mind, but the cost of all the stuff in it, and the expense + time spent living out of a hotel room (or with relatives) until your house gets rebuilt.
Quo usque tandem abutere, Nimbus, patientia nostra?
Well, if the system is based on the same air curtain setup as a hovercraft, liquefaction is a non-issue. Now landslides OTOH may be a bit tougher to contend with...
Quo usque tandem abutere, Nimbus, patientia nostra?
What's the deal with compressed air levitation. Is it good or is it whack?
It's fun
Can you be Even More Awesome?!
And with the added benefit of not being crushed to death by rubble in the process!
For planes and airships there's that whole "Oh no we're losing altitude, let's push the fat guy out" trope.
I wonder what's the weight limit for this little gizmo.
Add up the weight, washer, dryer, fridge, stove, counter tops, toilet, sink, water heater, computer, bed, my fat ass, a couple of dogs, , wife, some fat kids - what's going to lift all that plus a few tons of house?
There's a huge surface area under the house. Figure a house and contents weighs 80,000 lbs, and is 20x40 feet (or 115,000 in^2). So you only need to sustain .7 psi of pressure to float the house. A person can generate that much pressure from their lung - if the house was sitting on a airbag, a person could lift the house just by blowing up the airbag (though it make takes weeks or longer to fill the airbag). But without an airbag, since the air is constantly leaking out from around the house, it takes a huge volume of air to keep the house suspended. A 3cm gap around the perimeter is a huge gap and will require large quantities of air to sustain the pressure.
To move a large amount of air requires a large compressor. This is usually powered by electricity. Power often fails in earthquakes.....or does the system come with an instant start generator. You would have thought that they learnt from the recent tsumami. If the standby generators for the pumps of the nuclear reactor had been on the top floor instead of the basement, there may not have been a nuclear crisis. Generators don't like being drowned in salt water.
Nos Morituri te salutamus
And let's not forget that it wasn't so much the earthquake that devastated Japan. But it was the wall of water that mowed down everything in its path.
I'm not sure if you're aware, but earthquakes are much more common in Japan than tsunami are. Remember Kobe? There's a list of major earthquakes in Japan that might put things in perspective. Saving houses from substantial earthquake damage would be a major gain for the country.
(Mind, I'm not saying that tsunami aren't an issue -- just that earthquakes are also an issue, and a different problem set.)
Cheers,
"What in the name of Fats Waller is that?"
"A four-foot prune."
That doesn't seem like much. Am I wrong?
I thought it sounded like too much - you only need to lift it high enough to let it float side to side above the foundation. A few mm would probably be sufficient and wouldn't require as much air to compensate for leakage around the perimeter of the house.
Though maybe building it on teflon skids with breakaway support structure would accomplish the same thing at much lower cost - the support structure keeps the house steady in normal times, and during an earthquake, it breaks away to let the house slide back and forth. After the earthquake you just need to push the house back into place and rebuild the support structure.
By the way, wouldn't underground houses be better for earthquakes than something sitting on top of the soil?
I think I'd rather be on top of the soil in a wood framed (i.e. flexible) house than under ground where there are enormous ground forces trying to cave in the walls.
I just want a levitating house! Anyone for house air hockey?
After logging in slashdot still does not take you back to the page you were on. It's been that way for 20 years.
Housing ain't cheap, but most of the price goes into the land, and houses are viewed as somewhat disposable, most people expect a house to last about the lifetime of a generation. There are some companies that run commercials about a "100 year houses", implying this is a long-life structure, so that should tell you what the general expectations are.
Also, I don't believe the "being crushed" argument will be really critical, except in marketing. Most people seem to die from the fires that inevitably follow the earthquakes, not under the collapsed structures.
what if the power is knocked out in 500ms or less?
Not to worry, they've got nuclear power in Japan, it's proven to be very reliable during an earthquake. :^P
I don't care if it's 90,000 hectares. That lake was not my doing.
Housing ain't cheap, but most of the price goes into the land, and houses are viewed as somewhat disposable, most people expect a house to last about the lifetime of a generation. There are some companies that run commercials about a "100 year houses", implying this is a long-life structure, so that should tell you what the general expectations are.
Also, I don't believe the "being crushed" argument will be really critical, except in marketing. Most people seem to die from the fires that inevitably follow the earthquakes, not under the collapsed structures.
I'm living in a house that's nearly 100 years old now, and I'm pretty sure the landlord doesn't plan on tearing it down and rebuilding it any time soon. And this house has been through a number of San Francisco earthquakes since it was built in 1917.
Power often fails in earthquakes.....or does the system come with an instant start generator.
One likely possibility is that they keep a container of pre-compressed air on standby underneath the house. Then all the system has to do when the earthquake hits is open a valve to let the compressed air escape -- no power source necessary. (of course, this would mean you'd have to make trade-offs between container size, container pressure, and levitation duration... dunno if it would be practical or not)
I don't care if it's 90,000 hectares. That lake was not my doing.
Isn't that a long time to wait?
I'm sure they've thought of this, but in a house, that's a lot of mass that's been tossed around starting from the 0 mark. It seems at the one sec mark, the structure would already be unstable and that's when you're going to lift it up in the air?
Japan has an earthquake detection network that can give advance warning about a quake, giving a few seconds or longer of advanced warning. Long enough for the compressor to spin up, fill a pre-charge tank and wait for confirmation from a local sensor before dumping the tank and floating the house.
The earthquake and tsunami was the disaster, not the accident at Fukushima. There were dead people from the nuclear accident and 50,000 evacuated (not counting those in the evacuation zone whose houses have been destroyed by the tsunami) is a lot less worse than the earthquake's and tsunami's 20.000 dead + 500,000 evacuated.
... and the unwillingness of the Japanese to raise tsunami protection of cities, which reasonably enough was the same height for cities as for nuclear power plants, from 6m to 16m. Strangely enough, there was no finger pointing and no complaints about lacking tsunami protection of cities, where ... well, you know, people live (and died) and didn't get an advance warning of 2 days to evacuate before the tsunami hit.
Half a million were evacuated from utterly destroyed houses in an area now prohibited from permanent human habitation because of the tsunami hazard
The Fukushima Daiichi Nuclear Power Plant was screwed because most of the power generators were installed in a basement that was subsequently flooded and therefore useless to keep the pumps going to pump fresh seawater in to cool the cores, causing ongoing level 7 meltdowns at three reactors.
From the wikipedia page ( http://en.wikipedia.org/wiki/Fukushima_Daiichi_Nuclear_Power_Plant ):
"The reactor's emergency diesel generators and DC batteries, crucial components in helping keep the reactors cool in the event of a power loss, were located in the basements of the reactor turbine buildings. The reactor design plans provided by General Electric specified placing the generators and batteries in that location, but mid-level engineers working on the construction of the plant were concerned that this made the back up power systems vulnerable to flooding. TEPCO elected to strictly follow General Electric's design in the construction of the reactors."
The design basis for [the plant] for tsunamis was 5.7 meters. The earthquake triggered powerful tsunami waves that reached heights of up to 40.5 metres.
Around 4.4 million households in northeastern Japan were left without electricity and 1.5 million without water.
Sources: http://en.wikipedia.org/wiki/Fukushima_Daiichi_nuclear_disaster, http://en.wikipedia.org/wiki/2011_T%C5%8Dhoku_earthquake_and_tsunami
So say right that the power to the Air Danshin Systems Inc installation is taken out by an earthquake and there is no 'levitating' to be had? Aftershocks?
I doubt each installation would have its own generator and even if it did it would have to be left running in order to be able to kick in if power was lost.
Lessons learned, maybe not.
I don't care if it's practical or not - it's damn cool!
https://www.youtube.com/watch?v=lzSuuk4um44
A house doesn't sit on the entire square area of the floor space. It sits on maybe an 8-12 inch wide concrete or block wall around the perimeter of the house. So your 20x40 house is sitting on about 11,264 in^2 of foundation. This yields a figure of over 7psi.
My house wasn't designed to float on a cushion of air, but I'm certain that if you filled the crawlspace with 0.7 psi of air, it would float by the buoyancy against the underside of the floors. If I were designing the house to float, I'd give it a flat bottom.
But on the other hand, houses in San Francisco don't tend to substitute shoji screens for walls.
"[Regarding the 'cloud,'] ownership was what made America different than Russia." -- Woz
I've heard some stupid ideas in my time, but this takes the cake.
Seriously, man. Don't you think there could be a problem with a house that is not actually attached to its foundations?
What's the deal with compressed air levitation. Is it good or is it whack?
Many many houses in earthquake zones (like Memphis TN and surrounding regions) are barely attached to their foundations - often by a few rusting anchor bolts set into aging crumbling concrete. When a moderately big earthquake hits, many of those houses are going to fall off of their foundations, but unlike this Japanese house, they weren't meant to.
It looks like there is a robust outer band which encompasses the inner perimeter--much like telescoping tubes, a larger diameter one will "overlap" its inner one, preventing offset.
There is another issue: contamination of the surface. The Google-provided translation is rough but you get the idea (emphasis added):
Usually when the building is air ride on a thin cross-sectional, and basic artificial ground state so that adhesion to the ground, shaking it in a typhoon or clogged or something in between does not have any.
What one fool can do, another can. (Ancient Simian Proverb)
So use explosives to create your compressed gas instead. Your newly launched space station will make you the envy of the neighborhood and the terror of missile defense systems everywhere.
Supporter of the +1 Over Dramatic mod option. In memory of apk.
To move a large amount of air requires a large compressor. This is usually powered by electricity. Power often fails in earthquakes
.....or does the system come with an instant start generator.
Hope they remembered to add flexible connectors for all the utilities when they fitted this system.
Even an "instant start" generator is going to take several seconds to start. So you are going to need a big UPS.
500 politicians worth of hot air?
Excuse me, but please get off my Pennisetum Clandestinum, eh!
My house wasn't designed to float on a cushion of air, but I'm certain that if you filled the crawlspace with 0.7 psi of air, it would float by the buoyancy against the underside of the floors
More likely you'd break your house. Since by doing so you've completly changed how forces are acting on the structure. Instead of an air cushion it would be better off to apply thrust only to the parts of the house usually in contact with the foundations.
If I were designing the house to float, I'd give it a flat bottom.
With a slab foundation and designed to distribute its weight evenly over the base.
> housing ain't cheap in Japan
Housing is very cheap in Japan (cheaply bought and cheaply built).
Land is expensive. Not housing.
The point here is not really to save the house, but saving the people inside.
...the ground moves more than 3cm (in any direction)? It happens in major quakes; the 2006 tsunami was the result of the sea floor dropping over 2m. I've been through a 5-pointer, and the ground certainly moved more than 3cm, although it did move back as rapidly as it shifted. That one moved my entire house probably four inches and back, causing major structural damage (buckled window and doorframes, two cracks from foundation to roof) which is still being repaired after four years.. almost to the day, in fact(!).
Operation Guillotine is in effect.
Add up the weight, washer, dryer, fridge, stove, counter tops, toilet, sink, water heater, computer, bed, my fat ass, a couple of dogs, , wife, some fat kids - what's going to lift all that plus a few tons of house?
It's Japan. The houses are made of wood and paper. The tatamis floors are the beds. The water heaters are just-in-time. And the dogs are rented (you give them back the same night, or you pay a late fee).
4. Everybody survived and most belongings are fine, unlike the house next door that collapsed over its occupants.
Trust the Computer. The Computer is your friend.
As an engineer that has to do with compressors fairly often (though mostly on paper), I think your idea is much more sensible than installing a compressor. Compressors are hellishly expensive, require regular and competent maintenance (which is also expensive), and are prone to failure (more so than, say, pumps or valves). And anyway, a compressor that can start up and fill that kind of volume in a second is just a pipe dream; the study in the FA probably had a ludicrously overdimensioned compressor idling, and if you have to ask for how much it costs to idle a compressor 24/7 for decades waiting for an earthquake, you can't afford it—that's before considering its noise and how it would make your house uninhabitable.
My bet, however, would be on something like airbag chemicals. They react fast, the principle is well known and only needs to be scaled up. Compared to a valve, it is easier to build a fail-safe solution, and a large high-pressure air tanks will have all kinds of regulatory issues (for good reasons).
Victims of 9/11: <3000. Traffic in the US: >30,000/y
Houses don't bear their load evenly across the entire floor.
re-enforced floating slabs are quite popular for new homes (where I'm from in Australia at least), and also apparently seem to fair well in earthquakes
http://www.earthquakescanada.nrcan.gc.ca/info-gen/prepare-preparer/eqresist-eng.php#The_Site_Factor
http://en.wikipedia.org/wiki/Shallow_foundation
as for piers or stumps, i agree that shock absorbers (hydraulic or pneumatic) are definitely the way to go
It's the 21st century here in Japan. Any shoji screens still in houses are usually decorative or a just to give a little visual privacy.
We use real walls.
"...I can install this little blue button to get you down."
It seems like it would make more sense to build all single-family type houses on "stilts" that can flex and should a tsunami come in, the house just floats on top...
You obviously have never played Angry Birds.
The problem with 0.7psi is that it's 100PSF. 100PSF is about 2.5x the live load that house floors are designed to carry (it's actually an assembly load - think theater exits and dance clubs).
Is it just my observation, or are there way too many stupid people in the world?
Depends on the regulatory environment:
Because skyscrapers are understood to be an intrinsically harder problem than 1-3 story stuff, the problem of building them tends to attract actually competent engineers, as well as the attention of code-inspection types and the scrutiny of whoever is insuring the thing. Under good circumstances, that tends to mean that the building ends up being designed and constructed to survive expected earthquake intensities. Smaller buildings are much easier to half-ass and still get a working result that will collapse and crush the occupants when a quake hits, unless the building code guys are sufficiently up to date and sufficiently zealous.
So what does the shantytown version look like?
Something like this?
Thank you, Edward Snowden.
"Arguments from authority are worthless." —Carl Sagan
That's how NORAD's earthquake/atomic-shockwave-proofing works. The structures are mounted on springs.
Most people seem to die from the fires that inevitably follow the earthquakes, not under the collapsed structures.
This. I was in Tokyo when the earthquake hit and nothing collapsed. Some loose tiles and a lot of small items fell over, over there were no buildings falling down, ceilings caving in, vending machines tipping over anything like that. Japan is built to be earthquake-proof because anything that isn't won't last long. They must average a magnitude 5+ a month, and when it happens the trains stop for a few minutes and most people barely react.
Floating houses are not a new idea in Japan. Years back someone developed a system where the house was buoyant and would float if the area was flooded. It had foundations that could slide up and down (metal runners) so it wouldn't just drift away.
I'm not entirely sure what the point of this system is. Saving ancient historic buildings perhaps?
const int one = 65536; (Silvermoon, Texture.cs)
SJW, n: "Someone I don't like, and by the way I'm a fuckwit" - AC
Passive solutions already exist that can handle this. Basically the house is built on a platform that has domed feet (or roller-balls) that rest in metal bowls embedded in a traditional foundation. When the earthquake hits, the massive inertia of the house easily overcomes the high friction at these movement points, and the house nearly stays still while the ground moves underneath it. The bowls allow plenty of travel and have vertical sides to minimize the chance of the house skipping off the lower foundation entirely.
Inertia is a powerful thing, as an example one time I had to get my dad to give my little Samurai a tow to the shop. I tried to explain about carefully taking up the slack on the tow strap before moving, but as usual he couldn't be bothered with all my "nerdy overanalysis" and he just took off with a good 4-6 feet of slack in the strap. His crossover bounced back like it was tied to a tree (lucky the strap didn't snap), and he said that's what it felt like, and asked it I was holding the brakes down. Nope, that's little more than just the inertia of a 2300lb object.
"When information is power, privacy is freedom" - Jah-Wren Ryel
We use real walls.
Not according to wikipedia, which says timber frames are popular.
At least in the West, "timber frame" means that the load bearing structures are wooden beams connected by joinery. This is supposedly a much stronger structure than the stud-truss that supports most residential housing. The walls inside are still made of studs and drywall or studs, lath and plaster. Sometimes, "wood frame" is used to distinguish from "steel frame," meaning that the studs that hold up the drywall are made of wood rather than steel. In any case "timber frame" in no way connotes paper walls, let alone fusuma.
How else would you frame up a house if not using timber?
"Action without philosophy is a lethal weapon; philosophy without action is worthless."
It's the 21st century here in Japan. Any shoji screens still in houses are usually decorative or a just to give a little visual privacy. We use real walls.We use real walls.
Not according to wikipedia, which says timber frames are popular.
Only on /. would someone, in a different country, try to use Wikipedia to disagree with the reality of someone who actually lives in the country in question. Also, "timber frame" does not mean what you apparently think it does. The majority of homes in the US (and many other countries) are also timber frame.
How else would you frame up a house if not using timber?
Around here "real walls" are clay brick. Preferably double-brick with cavity between. So I took "real wall" to mean a solid wall.
Stone or concrete are acceptable alternatives, but more expensive.
I take it houses are made of wood-frame where you live?
You're unfortunately right about the expected lifespan of houses.
It doesn't have to be that way, though. Right now I'm renting a house that's 87 years old, and it would be nicer than any modern house if the landlord gave a crap. It's still structurally sound, the exterior is beautifully designed (if in need of a little TLC), and despite its exceedingly odd by modern standards floor plan, it's far more usable for actually living like a human being than most modern houses. Also, the fact that it's relatively small for the neighborhood means that we've got a much bigger yard for our dogs and garden than most of the rest of our street.
And this house is just a timber-frame with lathe and plaster on the inside and wood siding on the outside. I grew up in an old adobe house in rural New Mexico. It would be tough to say how old *that* house was, but I'd have to guess it was well over 100 years 20 years ago when I was a kid. I drove by it recently and it's been replastered and it has a new roof. It looks practically new. In England there are cob dwellings that are hundreds of years old. In Africa there are multi-story wattle and daub structures on rubble trench foundations that have been standing and occupied for thousands of years.
My childhood home was also much easier to work with than a lot of modern homes. All the plumbing and wiring was reasonably easy to access, and ran through conduits that went around the house on the exterior or pipes trenched around the outside of the foundation. My dad replumbed it and rewired the parts of it that weren't already to modern standards when my parents bought it. It cost him a few hundred dollars.
Meanwhile, one of my coworkers owns a house that's only about 20 years old in a big housing development, but she's already had to hire a whole crew to dig through the giant concrete slab that is under her living room to fix a leaky pipe, and she'll probably have to again. Some genius ran all the plumbing straight under the slab foundation when it was built, probably to save the $100 of extra pipe it would have taken to route it all around the house instead -- or to save the slight measure of fucking foresight it would have taken to just put the wet wall near the water and sewer hookups instead of on the opposite end of the house.
But when you're building houses and your goal is to build as many as you can as quickly as you can for as cheaply as you can, there's just no room for things like foresight, or spending a little extra to do it right, or even taking the slightest care when it comes to placing the house sanely on the plot of land.
I HATE modern tract-housing cheap-ass developer built "homes." They're sterile, they're shoddily constructed, and they seem to be designed by people who don't have a very firm grasp on the experience of actually...you know...living in houses like people.
There is no fucking reason to waste energy and resources to build a house that won't last at least a hundred years, unless you're a housing developer cutting corners on construction to rake in a little extra cash.
Porquoi?
There is absolutely no problem with "a house that is not actually attached to its foundations". In fact, it's one of the main principles behind a set of technologies employed in retrofitting important structures and also in recent structures whose integrity is fundamental to society. I could point you out to wikipedia on this one, but wikipedia's article on this subject is rather poor and useless. But to just give you a headsup, the principle behind this technique is to separate the superstructure (a frame, bridge deck, etc...) from the infrastructure (foundations, piers, frames, etc...) and then, depending on the technology, either prevent the earthquake energy to be transmitted to the superstructure, transfer it through a flexible connection or even transfer it through dynamic dampeners.
By the look of this article, it appears this technology fits in the 2nd category (transfer earthquake energy through a flexible connection). Yet, I really doubt it will go anywhere, as it is much simpler to resort to passive systems which are already widely deployed, tested in the real world and proven to work incredibly well, such as base isolation through neoprene bearings. So, probably this was the first and last time anyone will ever hear of this.
\\me is a structural engineer
Slashdot, fix your code or at least hire someone who is competent at it to do it for you.
As someone with 12 years of structural experience, currently studying for their Structural Engineering exam: You're full of it.
A "stick built" home - that is, one built with sawn lumber and plywood - is generally better than a steel or concrete structure. A properly designed wood structure is much harder to permanently damage during a seismic or wind event than a concrete structure, and is generally easier to repair than a steel structure. The problem comes in that our older homes and buildings are *not* designed properly.
Speaking personally - If I'm in an earthquake, I would rather be in a stick-built structure built in the last twenty years than in a Concrete building built within the last five.
This isn't to say that there is *no* damage - there is - it's just that it's primarily cosmetic.
-If it's worth doing, it's worth doing well.