Japan Creates Earthquake-Proof Levitating House System 243
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."
So (Score:5, Funny)
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.......
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"We, Kansas, in detail is not." - translationing "Toto, we're not in Kansas any more" into Japanese and then back again curtesy of translation.babylon.com!
LOL
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What's even more fun is that they get tsunamis there. House on top of an air cushion, streets filled with water, what could possibly go wrong?
Here's a quick test of one of the compressors (Score:5, Informative)
http://www.youtube.com/watch?feature=player_embedded&v=NubZJA4c_Rw [youtube.com]
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.
Tsunami are much rarer than quakes (Score:5, Informative)
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 [wikipedia.org] 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,
Re: (Score:2)
- today [tenki.jp]
- yesterday evening [tenki.jp]
Re:Tsunami are much rarer than quakes (Score:5, Funny)
I'm not sure if you're aware, but earthquakes are much more common in Japan than tsunami are. Remember Kobe?
I think so. Basketball player, right? I realize he was good, but equating him to an earthquake seems a bit over the top.
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The other problems include:
Lifting it without doing damage to the structure/contents
Needing to accuratly land the house back on its foundations.
How well it copes with vertical movement of the ground.
What happens in the case of ground liquifaction.
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Large structures sometimes use rubber and metal dampers that allows the structure to "float" in a similar manner. It makes for a much lighter construction as the actual building above the damping system doesn't need nearly as much reinforcement as a traditional earthquake-resistant design. The K supercomputer in Kobe is housed in such a structure, for instance.
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We already have a variety of options(elastomeric materials, springs, damped shock absorbers, etc, etc.) for building structures that are 'decoupled' from the ground enough to protect them from shaking with minimal moving parts and no active sensors, compressors, motors, etc. WHY would it possibly make sense to use a system that depends on the continued function and reliability of an active sensor system and a fast-acting compressed gas apparatus if you c
a sensor responds within one second (Score:2)
and generating the amount of air pressure to lift a house + all its belongings + its occupants takes how long? what if the power is knocked out in 500ms or less? why not make those rubber bushing systems more affordable instead of involving computer controlled "systems"
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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
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If I were doing this I would fill the bag from a CO2 tank. CO2 tanks are even commonly used in lieu of a compressor within city limits now.
Can't have too many guests (Score:3)
I wonder what's the weight limit for this little gizmo.
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For planes and airships there's that whole "Oh no we're losing altitude, let's push the fat guy out" trope.
Yes, that was one of the shortcomings of their previous system design [wordpress.com]
Don't care about the earthquake proofing (Score:4, Funny)
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Lateral displacements? (Score:2)
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The quakes in Japan, Haiti and California usually goes along with tremendous lateral displacements, so how will this help?
Isn't that exactly what this type of system is supposed to protect from? It doesn't matter if the ground below shifts laterally by a few feet, after the quake is over you just power on the compressor and get a few friends to help recenter it on the foundation.
Now a vertical displacement is a much bigger problem with this system...
The Starcrossed (Score:2)
Brings to mind the Ben Bova novel [amazon.com] where skyscrapers were actually huge rocket boosters. At the slightest hint of an earthquake they flew out into the ocean for a safe splashdown.
Car analogy please? (Score:2)
How much is an "incredible amount" of air? Can someone possibly explain this "air floating" concept in terminology of cars? Thanks.
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Tohuku Earthquake != Fukushima (Score:5, Informative)
Half a million were evacuated from utterly destroyed houses in an area now prohibited from permanent human habitation because of the tsunami hazard
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. 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.
The health cost of the releases of radioactive material from Fukushima Daiichi is incalculable. They were numerous and they were, in some cases, quite hot. And that's disregarding utterly the flushes into the ocean, or the likelihood of seepage.
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Raising walls is not really the answer for dealing with tsunami. They are looking at other options like placing things under the surface of the sea which will remove a lot of the energy from the wave, making it smaller.
Ninety-Nine Percenter version? (Score:2)
So what does the shantytown version look like?
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So what does the shantytown version look like?
Something like this? [brincojumps.com]
Power Outage? (Score:3, Insightful)
From the wikipedia page ( http://en.wikipedia.org/wiki/Fukushima_Daiichi_Nuclear_Power_Plant [wikipedia.org] ):
"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 [wikipedia.org], http://en.wikipedia.org/wiki/2011_T%C5%8Dhoku_earthquake_and_tsunami [wikipedia.org]
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.
Better video demonstration on model house (Score:4, Informative)
I don't care if it's practical or not - it's damn cool!
https://www.youtube.com/watch?v=lzSuuk4um44 [youtube.com]
Failure mode in lateral movement (Score:2)
1. House goes up on air cushion.
2. Ground below shifts sideways several meters.
3. House goes down off its foundation.
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4. Everybody survived and most belongings are fine, unlike the house next door that collapsed over its occupants.
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1. House fails to go up on air cushion since the compressor did not start due to brown outs caused by 10 million other compressors attempting to draw power at the same time.
2. Transformers and substations explode all over Japan, and emergency services are left without power.
3. Occupants die, but at least are saved the embarassment of realizing how much money their government obliged them to waste on a useless system when they made installation mandatory.
Just checked the date ... (Score:2)
It is 1st March, not 1st April. I'm still not convinced, maybe someone got the month wrong.
Rubber vibration mounts (Score:2)
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Small mounts can handle only small displacements. Large mounts are frequently used for large buildings but are too big for single-family homes and small commercial buildings.
All Slashdot geeks will die during the earthquake! (Score:2)
. . . when their basement lairs are filled with compressed air!
. . . um, maybe it's time to think about moving into the attic . . .
Roller skates ... (Score:2)
... and some big rubber bands ... in 2 directions.
What if... (Score:3)
...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 [thisisnottingham.co.uk], 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(!).
Not good... not good.... (Score:2)
The Fukushima disaster was a lot more than an earthquake. It was a tsunami!! Levitate your house off its foundation? Just makes it easier to wash away! You've got a house-boat and surf-board now.
Great (Score:2)
Just avoid the resonant frequency (Score:2)
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Luckily, air cushions have huge hysteresis losses which tend to act as dampers.
"For a small price... (Score:3)
"...I can install this little blue button to get you down."
Overkill (Score:4, Interesting)
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.
Re:Might be cheaper to just rebuild the house. (Score:5, Insightful)
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.
Re:Might be cheaper to just rebuild the house. (Score:5, Insightful)
And with the added benefit of not being crushed to death by rubble in the process!
Re:Might be cheaper to just rebuild the house. (Score:5, Interesting)
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.
Re:Might be cheaper to just rebuild the house. (Score:5, Interesting)
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.
Re:Might be cheaper to just rebuild the house. (Score:5, Insightful)
But on the other hand, houses in San Francisco don't tend to substitute shoji screens for walls.
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But on the other hand, houses in San Francisco don't tend to substitute shoji screens for walls.
On the other hand being crushed by a paper wall is far less likely than by one made of bricks.
Re:Might be cheaper to just rebuild the house. (Score:5, Informative)
We use real walls.
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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 wall
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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?
Re:Might be cheaper to just rebuild the house. (Score:5, Insightful)
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.
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An awful lot of people died from being crushed to death in collapsed freeways in San Francisco in the large earth quake in the late 80's. Not so much from fires if I recall correctly.
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Considering Japan was the nation that was pioneering 100+ year mortgages back in the 90s, I don't think those people are expecting a house to last only about the lifetime of a generation.
Re:Might be cheaper to just rebuild the house. (Score:4, Informative)
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?
Re:Might be cheaper to just rebuild the house. (Score:5, Insightful)
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.
Re:Might be cheaper to just rebuild the house. (Score:5, Insightful)
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.
Re:uhh.... (Score:5, Informative)
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...
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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...
A landslide just gives you some speed to make good your escape!
Re:Dumbest fucking idea evar (Score:5, Funny)
What's the deal with compressed air levitation. Is it good or is it whack?
It's fun [youtube.com]
Re:Dumbest fucking idea evar (Score:4, Insightful)
Re:Dumbest fucking idea evar (Score:5, Insightful)
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)
Re:Dumbest fucking idea evar (Score:5, Insightful)
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 [wikipedia.org]. 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).
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As an engineer that has to do with compressors fairly often (though mostly on paper),
You're probably thinking of the wrong kind of compressor.
Imagine a house (10mx10m), i.e. 100m^2. 1000Pa pressure (1/100 atm) would lift 100 Tonnes, which is probably about what a modern house of that size would weigh.
To lift it off the gound by 10cm, you would need 10m^3 of air.
The device to do that could be called a compressor, but it's more of a big-ass fan, to be honest. With such a low pressure, the fan doesn't need to
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Imagine a house (10mx10m), i.e. 100m^2. 1000Pa pressure (1/100 atm) would lift 100 Tonnes, which is probably about what a modern house of that size would weigh.
Ehh? A Pascal is a Newton/m^2. So:
100m^2 * 1000Pa = 100,000N
100,000N / 10m/s^2 = 10,000 kg = 10 Tonnes
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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.
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How do the cars do it? With electricity? You could bottle up the compressed air in advance. You could generate the air with a chemical reaction. Either way, just like the cars it's probably going to be an expensive system to maintain.
Re:Dumbest fucking idea evar (Score:5, Informative)
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.
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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 [wikipedia.org]
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Aren't skyscrapers already better for earthquakes than shorter buildings?
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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 sti
Re:About one inch? (Score:4, Interesting)
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.
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It needs more than a few mm.. There are vertical movements in a quake you will need some room for. I think a richter scale 6 is arround 30 mm movement. Well, actually the acceleration determines this, not the size of amplitude.
Also the one time protection will not work very well. A lot of times there is not a single earthquake, but multiple aftershocks, and those shocks can be as big as the original quake. If you have a system that is depend and on repair between quakes, it will fail.
Re:How big is the compressor? (Score:5, Interesting)
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.
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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).
How long would it take for a vaccum cleaner to fill it up? May be, having the air bag constantly inflated could be one way of assuring that it's deployed when there is an earthquake (or may be, it could be deployed through some sort of chemical reaction). In any case, would a 3 cm gap really be enough?
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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).
Re:How big is the compressor? (Score:4, Informative)
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.
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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 bo
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Re:How big is the compressor? (Score:4, Funny)
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).
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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 [nrcan.gc.ca]
http://en.wikipedia.org/wiki/Shallow_foundation [wikipedia.org]
as for piers or stumps, i agree that shock absorbers (hydraulic or pneumatic) are definitely the way to go
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More bothersome to me is that potentially the house could just shimmy itself right off of the foundation mid-earthquake with the airbag fully inflated and everything. Then it seems like the only thing your expensive little airbag does is protect the foundation itself fr
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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.
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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.
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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?
Remember though, that although there are different types of quakes, most in Japan don't seem to start at "full power", they ramp up over a few seconds. The March 13 quake for instance, did that.
Also, given Japan's current warning network, anybody not at the epicenter can get a few seconds warning even before the quake is evident locally—though maybe this is a bit pointless as it's exactly those who are at the epicenter that are going to really need the air cushion...
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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 (but is still anchored in place so it doesn't float away.) As far as I can tell it would be like building a "boat" on stilts, if an earthquake hits, the house stilts just flex (eg 8 stilts) and you can replace them if they are compromised. If a tsunami hits, well you may have to reconnect your utility lines (which should have auto-shutoff valves) but that's better than being crushed by the house coming apart or drowning after it's inundated.
But how high do you build the stilts? Peak tsunami waves after Tohuku hit 40 meters (the waves that innudated the Fukushima reactor complex hit 15 meters).
Save the area under the house for the car.
Some flood prone areas of the US already do this -- build a parking level on the bottom with slotted doors to let the water flow thorugh. My aunt had a house like this and after she evacuated, she thought her belongings were safe, until the flood water levels hit 12 feet -- 2 feet into the living area of the house.
It's funny really, there are actually many houses that are built in North America that won't last in an earthquake, because building codes are only heavily enforced for large buildings. Anything built before the 1989 Loma Prieta (San Francisco) earthquake, is likely not up to code. That's just 22 years ago. If you live in the Pacific area, you're sitting on a timebomb that can go any day now. I'm taking my chances in this 1960's apartment. I don't think the building would survive a Tohoku style earthquake, but I'm nowhere near any liquefaction area, so the worst that would happen is the damn building collapses on me. Luck would probably have it happen while I'm awake and could dive under my desk, but if it happens while I'm asleep, fucked.
I like to think that even my 1917 wood f
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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.
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Know-it-all Slashdotters chuckle from their parents' basement.
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air cushions under homes may well be what kills the occupants in the end, and it could be a malfunction or effects from an earthquake (static forces exceeding design limits, or dynamic effects like resonance).
a more practical solution might be to just incorporate shock absorption (dashpots) in your piers or stu
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a more practical solution might be to just incorporate shock absorption (dashpots) in your piers or stumps
to account for side-to-side vibration, pin all the connections and support side loads with dashpots as well (so the entire house is supported underneath in all directions by pinned dashpots).
depending on your budget, you could also go dashpot-crazy and build them into studs, joists, rafters, purlins, girts, etc.
you just need to ensure the natural frequency of the system is higher than expected earthquake frequencies, which would be part of your dashpot design criteria but the house as a whole should