Burning Man 2013 Honorarium Project / Impossible Triangle Now Made Possible
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Greetings

Hello and welcome, everybody.

In March, we were astonished and flattered to receive an honorarium art grant from the Burning Man organization to build a 17′ tall penrose triangle in the desert this year. Since, we’ve been team building, detail designing, prototyping, and getting organized. We’ve put this little site together to communicate updates to our supporters and encourage conversations about the project.

It seems like blogs make a good journal, so let’s start by catching up on the project.

Our first order of business was to get the right people involved. The project is being run by Blake Courter (me) and Blake Courtney, whom for your sanity we will refer to as “Hooch” and “Surley” as much as we are able. Surley is focused on fabrication, logistics, and assembly, and I’m focused on design, engineering, fundraising, and interfacing with BMorg. The first person to join the team was the incredibly talented Melinda Green to head up fundraising and PR, and you can already see her touch throughout this site. We were subsequently thrilled to have Michael “Dewb” Dewberry and Jacob Fenwick team up on lighting. Jacob and Dewb have been pioneering the use of emerging LED technologies, gaining particular notoriety for placing an order for over a half a kilometer of 60 LED-per-meter light strips in the fall.

I’ve been finalizing the detailed design and working with Surly to figure out exactly how we’re going to get it assembled. There are two goals of the detailed design process. The first is to make sure the design is structurally sound, and the second is to document it sufficiently for manufacture.

When optimizing the structure, there weren’t many surprises. Although the design is wrapped in triangles, its cross section is square, and therefore less stiff than a normal space frame or truss structure. It would be possible to add diagonal bracing beams without destroying the illusion, but it would prevent people from being able to travel around the inside. Adding diagonals was an easy, but worst-case fix. To preserve the openness, we extended the flanges where the corner cubes meet the arm beams so they act as gussets and stiffen each corner. It was also necessary to move to a thicker gauge of tube for the seven beams surrounding the two open faces of each cube. Here’s a nice shot of the detailed cube and flanges:

I’m not in love with how visible the larger, gusseted flanges are, but I do like the fact that the arms bolt on in a way the reinforces the gussets from bending.  It also means that the structure should be able to support 40 people with a safety factor of 10.

But fabricating it is another story, and Surly has been working out how to actually get it all assembled.  It’s not as simple as one might think.  For example, take what I thought was a clever way to assemble the cube:

I thought that was clever because each of the corner miters could be completely welded before inserting the diagonal pieces, except for one, which I figured would open enough to let the diagonals in without trimming them too much.  Not so.  But somehow, Surley figured out a way to get it done:

Practice cube for destructive testing

And there you have it: our first corner cube.  It’s mostly assembly practice, but I was impressed that Surley got within an eight inch of spec without even using a fixture.  It’s make out of slightly thinner stock than we will actually be using, but it was a good way to test loading on the diagonals, which are about the longest beams on the entire piece.  It’s mostly served its purpose, but Surley’s shop is in the back of the Green Cab warehouse where there are a few totaled old taxis rusting away.

Think that thing can hold up a decent-sized automobile?

-Hooch