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."
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.
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.
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.
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.