From: Ernie Aiken _at_ Worldflower Garden Domes (_at_)
Date: 03/22/00
Message-ID: <38D98B9D.698DA82D@gtwn.net> Date: Wed, 22 Mar 2000 21:12:29 -0600 From: "Ernie Aiken @ Worldflower Garden Domes" <wgd_at_gtwn.net> Subject: Re: Double-wall skin (was: ball connection)
What I term the "diamond truss" is the same idea (I think) where you get an
elongated =short, long pyramid or spherical diamond parallelogram, and is
simpler than the fully trussed domes on David's site. It appears that in a
typical arrangement, one is a Class I dome and the other a Class II (the
duals?). Either would be relatively easy to do with an emt dome. I think
Robert Conroy has one on his site. I present the concept that for a
greenhouse, you can have the inner and outer dome, both covered with the
inexpensive greenhouse films, with the result of an insulating air space
that's good for a helping warm greenhouse domes in northern climates. Also of
course that these domes are stronger because of more structure.
One of these types is also in Trinidad CO (Raton pass), a gym at the local
H.S. --
http://www.gtwn.net/~wgd/Casa_Manana.html
Here is a double dome drawing done in 3D solid model, a 4v. octa-dome
http://www.gtwn.net/~wgd/octa_4way.GIF
Proportions are 2 x 4s and 20 ft diameter, 3" cylinder hubs 12" long. Same
idea can be used for the double diamonded domes that are different types.
Using dome hubs to make space frames:
http://www.gtwn.net/~wgd/octa_pyramid_array.GIF
http://www.gtwn.net/~wgd/tetra_pyramid_array.GIF
http://www.gtwn.net/~wgd/tetra_pyramid_array2.GIF
Ernie
"J. Michael Rowland" wrote:
> Charles J Knight wrote:
>
> > Do you mean something like the twin-layer geodesics on
> > http://w3.one.net/~monkey
> > that David was working with? He's been making geodesics
> > that have a warped octet truss as the skin, rather than
> > a single layer, in a hope to increase the local strength
> > and resistance to buckling.
>
> David's making his skin out of a truss arrangement. It's a lot more
> complicated than what I had in mind (but they are beautiful things,
> aren't they?).
>
> I was proposing something more along the lines of the way the struts work
> in a tensegrity sphere -- actually crossing under a vertex to connect two
> non-adjacent vertices. Sort of a skin-and-a-half, rather than a double
> skin.
>
> It's kind of wasteful of space, so you'd probably only want to do it in a
> BIG dome... but since we're talking about high-frequency domes, maybe
> that goes without saying. I could also see it working in smaller domes,
> if you leave off the "inside" skin and use the interconnect struts as
> decorative elements, the way some log homes are built with exposed
> trusses. These could be tension members, though, not compression members
> as in a tensegrity, so you could get away with steel cables instead of
> struts... something that could even do double-duty as, say, a track
> lighting grid inside your ceiling... or supports for hanging plantings...
> even hydroponic containers for trailing plants. (I've always wanted to
> live in a house with ferns and vines trailing down the walls....)
>
> jmr
