Surviving a meteorite strike - a research proposal

Domes are strongest, pound for pound. If you don't like being stuck with a circular plan, you can take an arch and extend it into a vault for a rectangular plan. An A-frame is also feasible - some Egyptian pyramids have chambers built this way. If the roof slab is tilted up in an A or some other way, you can put the top above ground and get some really cool architectural effects with windows. Tilted slabs have to be thicker than dome shells, but this doesn't affect the cost much.

The problem common to all types of raised roofs is thrust, the outward force exerted by the roof on whatever supports it. You can't count on soil supporting it because soil unavoidably settles laterally on the order of inches when you can only tolerate movement on the order of 10ths of an inch. You have to support thrust with the structure itself, or solid rock. Perfectly doable, just relatively expensive.

I have chosen flat roofs, which transfer their load directly through the walls, which mitigate the effect of foundation settlement. They are also very cheap and easy to build.

An interesting thing to play with is the layout of the walls. The honeycomb (hexagons that share sides) is the most efficient way to partition a space. If you keep the sides small, ~6 ft, and omit sides to make larger rooms, you can come up with some good floor plans that turn out to be really strong.

To answer you directly, pros for an A-frame are aesthetic effects (lighing and a sense of space), better draining than a flat roof, and easier construction than a dome.

Cons are the expense and geometric limitations of handling thrust. Most architects who do earth-sheltered homes incorporate A-frames in one way or another into their designs. But I should also say that most architects are really bad engineers :)

Scott

PS: I should probably state explicitly that an A-frame proper is identical to an A-frame roof with no walls. This is the comparison I intended, but it seems less than clear as I reread it.
 
Hi all,
Sorry to join the thread so late but this is an area I may be able to help with. I've built straight and alternative homes in western WA and have done a fair amount of research.First off,forget about solar energy in western WA for anything but minimal lighting,not only would it break your budget but an array sufficient to run a heat pump would have little chance of surviving the event.Efficiencies for PV panels under WA cloudcover are less than 10% of rated and only for 5-6hrs a day in the winter.A $50,000, 10,000 watt system might produce 5KWH a day,that's about $.25-.40 on your power bill depending on which grid you're on.Of course on a sunny day you'd get big spikes but then you'd have to store the power...diesel would be much more cost effective.
A pacific ocean strike would leave all of western WA a wasteland,I doubt very much it would be survivable.
When you design your earth sheltered home keep defensability in mind,there's no sense building a shelter for someone else to use after you're dead,a glass wall on the south side of the shelter leaves you no place to hide unless you have some sort of steel shutters.When the supply lines into the metro area breakdown it won't take long for the masses to find your hidey-hole.
About that glass wall,if it does go dark it becomes a huge liability,might want to insulate those shutters too.Also many people are unsettled by the effect of all the light entering the house from one direction,it can get very annoying after a few years.
I've built several concrete structures wrapped in ext. polystyrene that worked very well,you've got to totally isolate all the concrete(with the possible exception of the floor) from the surrounding dirt if you ever want to heat the house above deep-ground temp.using all that concrete as a giant heatsink almost totally eliminates daily temperature fluctuations.
If you're planning on greenhouses and livestock consider integrating them into the house,you'd be amazed at the amount of heat a few hens generate in a well insulated space. There's lots more to say but this post is getting long,anybody interested feel free to email me.
 
Originally posted by Brent VanZanen
A pacific ocean strike would leave all of western WA a wasteland,I doubt very much it would be survivable.
Click to expand...

How big are the tsunamis expected to be from an ocean strike? How far inland will the run/what elevations are "safe"?
 
Tsunami surges reported in NASA newsletters are usually in the order of 1-3 kilometers high for a deep ocean strike. The Willipa Hills separate southwestern WA from the coast, ~2000 ft (600 m). Even though the actual estimates are highly variable and the processes are still very poorly understood, it is entirely possible that most lowland west of the Cascades will be destroyed.

Due to the joys of wave mechanics, the situation would be much the same in New Zealand, Japan, Australia, etc., etc. Waves that size don't die out much with distance.

The danger is not so much the water as it is the debris that gets picked up. Imagine a wall of concrete-like stuff hundreds of feet high, picking up everything above basement rock for a few dozen miles, then depositing this mass over a few hundred.

Brent's statements about solar-electric reliability are what make me consider it "icing on the cake."

Brent, what experience have you had with passive solar, say heating water in tubes or air by running it through a greenhouse? Are you familiar with the homes at Doty?

Scott
 
I've used an attached greenhouse to heat a mobile home in mason county, 10mo. out of the year it needed no heat.From christmas to mid feb. it only needed a very small fire.I kept birds,in a coop attached to the attached greenhouse and they kept the greenhouse warmer at night than before they were there.My last house I built from scratch required no heat at all in the walk-in basement, which was built like an earth sheltered home,just with a house built on top of it.It had a fair amount of glass facing south,and all concrete construction wrapped in foam to R20 below grade and R30 above.you have to provide a method of venting the greenhouse and closing it off from the living space and those insulated shutters I mentioned are a must to keep cool in the summer. leaving the slab uninsulated but running your insulation 2' below the floor and 2' out around the perimeter gives you a deep-earth link without too much direct heat loss.I've used a passive solar/wood hot water system with some success,it would work fantastic in a survival or homestead situation where somebody is there all the time to monitor it,but it's not very practical for the average Joe with a job.In a sunny winter climate it would work better.

Of course the survivability of an event would depend on it's size and location,but an event like we're talking about here would be very bad for the whole pacific rim in the likely event of a pacific strike,not only would the tsunamis flood all of western WA,(even if you're in the shadow of a mountain it will still reach you)but the likelihood of catastrophic earthquake/vulcanism is very high.
 
Have you considered rammed earth construction? You would be trading earthen walls for concrete and above ground for below ground but many of the same benefits are there.
 
Rammed earth is very good, particularly when a lot of cement is mixed in. Its major advantage besides low cost is insulating power, for both heat and sound.

The strength to weight ratio of rammed earth makes it difficult to design for earthquakes and roofs. The major reason for this is that the compressed, cemented soil cannot adequately grip rebar in support of all that weight. But you can do it with big tie rods like they put in old brick buildings. Anything built out of stone or masonry can also be done with rammed earth.

If you use a typical design strength for rammed earth of 800 psi and compare that to typical concrete (3000 psi for plain-vanilla), you get a wall thickness of 30/8 = 3.75 times as thick as you would use for concrete, which usually means a couple of feet.

For a rammed earth roof, you would almost certainly have to use an arch with large ties connecting the ends. If it were me, I'd want the underside shotcreted too, so pieces couldn't spall off.

Scott

PS - You can still do a structure below grade, it just takes more effort to waterproof.
 
Brothers & Sisters of Duration Hibernation,
beezaur et alia,

Here's some information you can appreciate:

http://www.mitutoyo.co.jp/eng/keisoku/hold/chika.html

Underground means at a depth to maintain a stable temperature. Deeper is better. Additionally the impact may effect polar position creating an entirely new set of poles and equatorial region as a result of the angle of impact. Destabilization of a degree can hurl the earth into this condition.

Take a look at this site:

http://www.habtheory.com/

Life will go on. (And you'll no longer have cable bills, phone bills or any other kind of bill!)

Regards,
Lance Gothic
Shibumi
 
"Additionally the impact may effect polar position creating an entirely new set of poles and equatorial region as a result of the angle of impact."

True, except that Earth has a LOT of rotational inertia. It is like a spinning gyroscope in this way, very difficult to tip over. The solid crust is only a few km thick on an otherwise mushy planet 13,000 km in diameter. An impact of that magnitude would peel most of Earth like a scalded peach and splash up a Saturn-style ring of frozen magma droplets. The engineering term for that is "bad."

Cool links - is the HAB book a good read?

Meanwhile, back at the NASA newsdesk, excepts from some emails regarding impacts:

"WASHINGTON -- This summer, much of the world watched as India
and Pakistan faced-off over the disputed Kashmir region,
worried that the showdown could escalate into a nuclear war.

Coincidentally, U.S. early warning satellites detected
an explosion in the Earth's atmosphere June 6, at the height
of the tension, with an energy release estimated to be 12
kilotons.

Fortunately the detonation, equivalent to the blast that
destroyed Hiroshima, occurred over the Mediterranean Sea.
However, if it had occurred at the same latitude a few hours
earlier, the result on human affairs might have been much
worse. . ."

And this one:

"ALBUQUERQUE, N.M. - Rings around the earth?

While most of us know about rings around Saturn and Jupiter, some scientists
believe there once were rings of rock debris around our own planet. Two
scientists - Peter J. Fawcett, of the University of New Mexico, and Mark
B.E. Boslough, of the U.S. Department of Energy's Sandia National
Laboratories - have suggested that a geologically "recent" collision (about
35 million years ago) may have caused such a temporary debris ring.

The two also suggest that such temporary rings - lasting from 100,000 to a
few millions of years - may explain some patterns of climate change observed
in the earth's geological record. These conclusions are spelled out in an
article in the Journal of Geophysical Research, Atmospheres, August 16
edition. . . ."

Scott
 
Brothers & Sisters of Duration Hibernation,
beezaur et alia,

An excellent read! The first hundred pages are preparatory to be sure. The basis of the information provided thereafter will give you pause. Relevent? Timely? After seeing the impact of Jupiter a few years ago the premise resurrected this book into what may become a strong if not "best" seller!
Personal preparedness will be the most important quality in any of our lives. We may not have an opportunity to have access to bail-out-bags, (B.O.B.'s), our homes or many other services presently available. Each of us will live by our wits and our personal sense of survival. As is the motto of the Boy Scouts "Be Prepared".
Everything else is moot.

Regards,
Lance Gothic
Shibumi
 
I saw a Turbo Burn Water Jacket Stove at the Puyallup fair one year, and always wondered how well it would work. Well, the local school here uses one that burns waste oil, and it is very effective. The web page there shows typical usage and accessories.

I was considering it for a potential power blackout scenario, what with the west coast demand on power and the likelihood of a couple terrorists taking it out. But I suppose one could consider it for this scenario as well. Worth a look, and very inexpensive considering what you are gaining from its use.

Beezaur, where are you? Doty/Willapa Hills is just a short drive from here.
 
T 13 N, R 4 W, W.M.

I can see Baw Faw (a.k.a. Boistfort) Peak from my kitchen window.

Scott
 
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