Thursday, March 25, 2010

When Fuller means Less: the weight is over.

I wanted to design a masonry unit (block or brick) which could assemble into an entire structure, including a roof. A sphere seemed like an obvious solution, part of a sphere could be used as a dome.

Work by others such as R. Buckminster Fuller and Barnes Wallis had helped to pave the way. “Bucky” was an odd individual who had some real insight and developed some interesting ideas. He applied himself to doing the most with the least: to enclose the greatest possible volume with the least possible amount of material. This eventually led to what he called a “geodesic.” This sort of geometry has been known since the ancient greeks. I find the Roman Dodecahedron pretty fascinating, their use is still a mystery.

Bucky Fuller used the weight of a structure as a criterion for evaluation. To his way of thinking, if a structure weighed “too much” it was no good. This somewhat arbitrary criterion excluded using inherently heavy masonry as a construction material. For Bucky, structures should be made using the mass-producable methods developed by the US during the war effort of the second world war. Houses should be made of materials like aluminum, mass produced in factories, and we should be able to drop them on site with helicopters. Airstream styling for a brave new world. Look at his ‘dymaxion’ car and house, you get the feel for it.

It turns out that the ‘geodesic’ template lends itself very well to masonry construction. I worked on the specific case of a truncated icosahedron. This is the geometry of a common soccer ball (football for non-Americans) where the black patches are pentagons and the white patches are hexagons. By subdividing these hexagons and pentagons into their respective constituent triangles, we begin to get close to manageable unit shapes.

To make a larger structure, a given unit triangle is simply subdivided into four smaller triangles. By doing this, the unit shape for a large structure can be kept small and manageable for construction purposes.

In considering assembly, I thought it would be advantageous if the blocks could interconnect, or lock together by some sort of retaining system. At first I had a simple hole located on the side of each block, into which a pin could be inserted, connecting two adjacent blocks.

In order to economically mass-produce these unit shapes, they would have to release from a two-piece mold (the sort used by the block industry) without any draft, or undercut, or negative angle. A simple hole to connect blocks -like I had first thought of- creates an undercut. These holes would have to be drilled after the block was made. This was expensive, time-consuming and impractical.
Another obstacle to the idea of interconnecting blocks was that they had to assemble without any undercut. An interlocking feature –by definition, almost- creates an undercut, or draft, or negative angle. An interlock can prevent the blocks from being assembled. How could this be done? That’s for tomorrow.

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