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Second email to Kenneth Snelson, Re: Your email message

Date: Mon Apr 26 10:10:10 1999
From: Robert Burkhardt <bobwb@channel1.com>
To: Kenneth Snelson
Subject: Re: Your email message

Hi Kenneth,

Thanks for accepting a copy of my book. I sent it on its way Friday at the book rate so it should be to you in about a week.

Thanks for quoting me the dictionary on ephemeral. I never thought to look. Student of Einstein that he was, Bucky I guess didn't think much of using a time-based concept to express a volumetric one. I have put a caveat in my caption for the tower, and will also adjust my tensegrity prospectus (light weight and gossamer appearance?).

>>I also think there is some hope for tensegrity domes at least with
>>double-layer technologies. I was quite surprised at the rigidity of a
>>couple low-frequency double layer spheres I built.

>What you must keep in mind -- although hard to keep in mind until you've
>built a full size structure such as you're contemplating -- is that the
>sheer mass, the weight and the scale make unimaginable changes in the
>performance of what, in a model, seems not all that dramatic. Also,
>constructing -- assembling -- such complexes is profoundly challenging
>since they're essentially floppy until the final tension lines are
>attached. Even if it were possible to encapsulate a city as Fuller claimed
>in his writings, constructing it in-situ would be the most daunting part of
>the entire enterprise. And why would one want to do it that way? in any
>case, when there are numbers of good, sound, pin-jointed dome systems that
>are fairly firm structures even when they're not fully assembled.

Assembled top-down, the double-layer tensegrities are fairly firm in mid assembly. I've developed a methodology for computing self-stresses and responses to external stresses (e.g. gravity) for tensegrities. I certainly don't know what things will look like at those large frequencies, though initial computations give me some optimism. I really need to get more computing power. I also need a structural engineer if I'm to convince anyone else.

For my first city I think I'd choose a desert area where snow loads didn't have to be dealt with. Mark Somers has suggested a dome over Tuscon which I think might help with water conservation, climate control, energy harvesting and environmental impact.

The "cover a city" (or whatever) idea reminds me of Christo's efforts somewhat. Maybe I should try to recruit him.

I'm currently assembling another obelisk. It will be about 17 feet high and uses your diamond topology though in a highly skew way. You can expect an acknowledgment in the press release. I tried a zig-zag topology the last time and it seemed too weak though just adding another set of base tendons may help a lot to control the tilting problem I had. I'm attaching an illustration.

So I'm glad my caption caught your attention though I again apologize for my short-sightedness. The caption has certainly much improved with your comments, and I would appreciate any you might have on the book.

Bob Burkhardt

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