Strength and thermal-management qualities of geodesics vs monolithics
stillprepping said:
the 'seams' are filled with a special blend of elastomers and cement that dont crack.
A crack is not a cold joint, and monothic domes are made with the same formula...
monolithic.com/construction/mix/index.html
http://www.monolithic.com/construction/flyash
...and, additionally, monolithic domes benefit from compression of the concrete by the force of pneumatic shotcreting and from an improved curing environment. Pasting concrete onto the outside of a building is not the same thing as shotcreting the inside. The concrete placed on the insde by shotcreting will always be stronger, given the same ingredient formula.
Personally, I would use PVA fibers instead of nylon fibers, and I would use silica fume in addition to or instead of fly ash. This should give much greater strength to any building, given that the suring process is controlled (silica fume concrete requires much-greater humidity -- something that can easily be provided in the controlled atmosphere of an inflated airform). For absolutely maximum strength, I would use reactive powder concrete with no large aggregate and I would cure the concrete immediately after shotcreting by autoclaving (steaming) the interior of the dome at 195 degrees Farenheit for 4 days. That should produce ~30,000 psi compressive- and ~1000 psi tensile- strength concrete.
concreteproducts.com/mag/concrete_lafarge_introduces_psi
stillprepping said:
i'm not aware of any ai domes that have ever exploded.
There are no AI domes that have been exposed to serious tornadoes. On their web site, they admitted that their domes only computer model as safe up to 230 mph.
http://www.aidomes.com/faq_strength.htm#S1
Right below that, it says, "The standard design will accommodate 150 mph winds."
http://www.aidomes.com/faq_strength.htm#S2
A 300 mph wind produces four times the force of a 150 mph wind. All Monolithic Domes will easily withstand 300 mph winds, and it says this all over the Monolithic website.
It also says, "Our panel withstood 170 lbs. per sq.ft."
http://www.aidomes.com/faq_strength.htm#S3
A panel is not a building. The forces in a geodesic dome are carried in the struts. The strength of the panels is irrelevant to how the building will perform in a tornado.
There are Monolithic Domes buried 30 feet deep, carrying one ton of dirt per square foot.
monolithic.com/plan_design/survive/index.html
If the panel is the strongest part of the AI dome, and it can only hold 170 PSF, AI domes are indeed not very strong. The main problem seems to be that AI domes are geodesic domes, and geodesic domes are inherently weak structures.
the sections of ai domes are solidly joined with iron (i believe) and are extremely strong.
I could not tell from the AI website what their kit pieces are joined with. Monolithic Domes are joined with continuous crisscrossing rebar tied with wire ties and embedded in monolithic high-strength shotcrete.
what i particularly like about them is that the outside is reinforced concrete and resists flying debris better than the monolithic dome whose exterior is of fabric over foam over concrete. i had a sample of the outer fabric, and it IS extremely tough. but i'd imagine that tree branches and other sharp stuff flying around a high speeds would tear into it.
That is why people coat their monolithic domes with things like chainshell and Rhinoliner. Rhinoliner is used to coat pickup truck beds. Ray Ansel has been using it to coat the monolithic domes that he is not burying.
Chainshell is a pretty cheap option. It is simply chainlink fencing embedded in stucco.
monolithic.com/construction/coatings
This is related to another thing that is inherently wrong with the AI dome. It has the thermal mass (the concrete) on the outside, and the insulation (styrofoam) on the inside. This is backwards and will drive up your HVAC costs.
monolithic.com/plan_design/cuthbertson/
Also, moisture will be drawn through cracks in the stucco to the cold concrete. The result will be a home filled with toxic mold.
monolithic.com/plan_design/vapor_drive
http://www.monolithic.com/plan_design/belowgrade
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"...not insulating properly will invite condensation.
"So, the most common cause for failure of underground houses is not gross heat escaping the structure but an interior surface temperature that allows condensation. South uses a simple demonstration to prove his point: a glass of ice water sitting on a table. "The ice water is obviously taking on heat from the room," he says, "and if there were millions of glasses of ice water they would cool the room. But there's only one. Still that one proves the axiom opposites attract. The heat in the room is attracted to that glass of ice water, and since the surface temperature of the glass is far below that of the room, moisture condenses and begins running down the glass."
According to South, an underground house can be compared to that glass of ice water. He says, "The moisture in the air condenses when it contacts cool outside walls.
Though there may not be enough moisture to run, it will be enough to attract mold and mildew.
"The only answer is to have enough insulation so that the interior surface temperature of the walls equals the temperature of the air inside the house."
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The outsides of AI domes have no insulation -- this is a recipe for disaster and also happens to be one of the principal reasons that geodesic domes have such a poor reputation with the public.
as for other doors...how about a 5 foot thick concrete and steel silo door? 
