Large hexayurt-style domes – a problem solved
by Vinay Gupta • May 15, 2010 • Everything Else • 13 Comments
Edmund Harriss has solved a problem I’ve been working on off-and-on for nearly 15 years. This is splendid. Back in 1995 or so I was challenged with reducing the waste involved in making geodesic domes for Worldview Livingspace a nascent dome company. I couldn’t get the waste below about 25% because of the poor fit between geodesic triangles and 4′x8′ sheets of plywood. This has been a perennial problem since the start of geodesic domes.
In 2002 I had a breakthrough – do the simplest thing that could possibly work – and I invented the hexayurt. I figured out some simple ways of making bigger hexayurts but never really cracked a geometry for making truly large zero-waste structures.
A couple of weeks ago I asked Edmund about it. A couple of days later I got plans and models. The “nearodesics” are zero-waste like the hexayurt – whole sheets and half sheets are the only pieces used – but are large – about four times the size of the hexayurt, and there is good reason to believe that even larger structures of this basic design are possible using different geometries.
This PDF describes the new large structures and has laser-cut plans for the models you can see at the link above. This is very exciting work indeed, and I’m looking forwards to working with Edmund on building some of these things full sized soon!
These are great. Nice work
I look forward to seeing the assembly choreography for the big one. Hinges may be called for.
Extremely cool. The size is great, and a side-benefit will be that having more than one options for an attractive-looking structure will make them more attractive to those who might want to live in them.
Anyone making these for Burning Man 2010?
…and I wonder if they’ll give better hurricane/wind tunnel performance than a hexayurt of the same size. Certainly they look more streamlined, so it’s probably a matter of how well they do the geodesic-style force-distributing thing.
• brilliant !! [1] Don’t miss that great PDF in the last paragraph. [2] I note that the floor areas of the three solutions are 111, 429, and 448 sq.ft. It seems like a small gain between the tri and quad domes. Can a friendly mathperson please calculate their relative interior volumes?
Vinay, I think I’m in love with the Tri-dome. Have you calculated what the actual dimensions are when using 4×8 plywood? (I’m sure you have.)
What is the wall height?
The center height?
The distance across the floor?
Possible to install guttering at the bottom of the frame (just above ground level) for rain-water catchment?
Final question: Do you see a simple way to double the height, with a second round of frame at the ground level? That way, one possibly could frame a freestanding large loft inside and add about 1/3 to the actual living area floor space.
I’m looking at the triangles/squares and imagining inverting them and am not seeing that working. Am guessing that it is not possible to create a six- or eight-foot tall base frame that a tri-dome could sit atop.
Looking forward to seeing the numbers. And seeing if I can’t put up a full-size model this summer.
Am intending to play with the paper model this week.
And…. Am wondering it one of these would leak as does the typical geodesic dome. (I’ve yet to know anyone who built and lived in one who didn’t suffer tremendous water intrusion, including Dave Jensen who built his in 1959 using a Buckminister Fuller-licensed kit.)
Best,
kwc
Pingback: The Bucky-Gandhi Design Institution › The New Hexayurts
Fantastic design! i agree with Vinya, that these might not hold up in more extreme conditions using insulation board (the playa, for example) however it should be a very simple matter to build a framework for the Tri dome out of EMT conduit at very low cost. Nothing like as strong as a geodesic, however once you tie it down it should be very resilient!
The Quad dome presents a different challenge, since the flat roof would tend to sag downwards if a frame was made… you know, you could make a very strong and rigid framework for that one out of dimensional lumber:
Make 4 frames that are the “roofs” that you are leaning together. A bit of work with beveled and compound angles, but not too complex, and a regular chop saw (or handsaw, using jigs) will suffice.
At the six point junction, put one eye bolt through each timber, vertically, eye facing inwards (as you look at the structure) a few cm from the end of the timber.
At the three point junctions, it’s more tricky since you want re-usability… I would use heavy, perforated metal strapping on inner and outer sides of the junction with at least 2 bolts on each side of the junction, and another piece of metal strapping shaped like a flat “U” that wrapped around the whole junction and bolted to the inner timber at the junction from the outside sunk into a tee nut on the inner timber, as well as having at least two bolts attaching the strapping to the inner timber.
With this method you would have to let the inner timber in a bit to accommodate the strapping, but once assembled it should be very stiff.
OR…
Back 1″ insulating panels with plywood (1/4″ or so?), face the plywood inwards, make 6 or 8 evenly spaced small holes near each edge of the joins and “stitch” the panels together with cordage after you tape it up outside. You would probably pre-stitch the compound panels first.
LOTS of ways to do this I think…
Edit: Just thought of a way to use conduit on the quad dome as a framework… since the main thing we are concerned about is sag at the top center, and since the “roof” sections are actually going to be quite stiff in the other direction, you could make the frame, attach the panels to it, and run cordage or cables in a “V” shape from the vertices of the square, down to the center of each roof section, through an eye, and then tie it down to a stake. Not only are you getting stiffness in the same way as a sail shroud, but you are tying the structure down very well.
Hi,
I’ve been a fan and builder domes and hexayurts for years. Thanks for your work, which I will spend more time later.
In the meantime, you should know that Buckminster Fuller himself designed a simple and waste-free plywood dome, later perfected by Steve Miller. See http://www.sover.net/~triorbtl for details. If you want technical instructions from his Back Home articles, email me.
Also, Chuck Henderson observed and solved the same problem 40 years ago–and received Fuller’s blessing in person–with his http://conicshelter.com
There is nothing new under the sun.
Sincerely,
Andrew Durham
Yeah, those are cool, but they leave honking big holes in weird shapes that they’re covering with plastic! That’s not the point **at all**.
There totally is something new under the sun: the nearodesics actually solve a problem Fuller never even got close to – making a dome that really scales…
Oops:
“…(including BENT plywood walls if desired),…”
Ok, I’m a little slow. By “scale”, you mean “get widely/rapidly adopted” not “increase in size”. I had trouble registering this use of the word last week, too.
Even so, I think domes caught on remarkably well considering Fuller patented everything and was miserly with what information he let out about them. One article in Popular Mechanics with chord factors was enough to launch thousands of dome projects.
Steve Miller brings an astonishing perspective to this (see both links for whole story) Basically, due the info blackout, domes got built with the unsuitable methods people knew, not those Fuller intended, and domes failed massively. Despite Miller’s 20 year crusade to show what domes were meant to be, their reputation never recovered. The wave of enthusiasm had passed. Now domes were exactly what the straw man slayers at refrieddomes.com said they were.
After building a handful of domes myself, framed and frameless, I wrote a short piece http://andrewdurham.com/links on the main lesson I learned: architecture *means* shell/frameless construction.
The hexayurt is in my top five examples of shell construction on that page. I really like it. And open-sourcing it was a brilliant correction of Fuller’s political error. But I think your experience with the econ-o-dome misrepresented geodesic construction. I wish you’d look at this one more time from Miller’s point of view.