05 December 2014

Geodesic Domes

Domes: A General Introduction

There is nothing new about domes - their use in architecture is well documented and many examples abound. It was the Romans who first fully realised the architectural potential of the dome, along with the Byzantine builders of the Hagia Sophia in Constantinople. Other, similar examples, include the Taj Mahalor the Dome Of The Rock in Jerusalem. There's good reason for this indulgence in domes, too: ignoring aesthetics for a moment, on a purely practical level the sphere is efficient. It encloses maximum volume with minimum surface; that's why bubbles are spherical. A dome-shaped building, therefore, has maximum volume within it, and a minimum surface area through which to lose heat or sustain damage. Domes, when it comes to building, are efficient.

Geodesic Domes

So what's special about geodesic domes? A geodesic is, basically, a curve which gives the shortest distance between two points in a curved space. In terms of a spherical surface, any curved line which follows the surface of the sphere forms part of a great circle - a circle which cuts the sphere exactly in half. Drawing many of these on the surface of a sphere, a set distance apart, splits the surface of the sphere into many triangles, all with curved sides.

By reproducing this network of triangles, the sphere is quickly constructed. Now, bearing in mind that efficiency is one of our main reasons for producing the dome, we're only interested in producing the top portion of the sphere. Similarly, we'll have none of this curving going on. For our purposes, straight edged triangles will be fine. Okay, so our dome won't be exactly spherical, it'll be more of an approximation to a sphere, but all's fair in the name of efficiency and ease of construction1. It quickly becomes obvious that a geodesic dome could be constructed quite simply from multiple identical parts, joined together to form a triangular structure. (Indeed, one is tempted to run amok with drinking straws and pipecleaners, just from thinking about it.)

Once constructed, the geodesic dome distributes loads evenly throughout its structure. Incredibly strong, they simply shrug off earthquakes unless their actual foundations are undermined or swallowed up. Hurricane damage is far less common - there has so far been no reported damage by hurricane to a properly-designed geodesic dome. Best of all, as the size of a geodesic dome increases they become stronger, lighter and cheaper per unit of volume - quite the opposite of conventional buildings.

Walter Bauersfeld and Buckminster Fuller

It is impossible to mention geodesic domes without dropping in Buckminster Fuller, famed for his work popularising the structures. Similarly, though he is less associated with these architectural marvels, Walter Bauersfeld deserves more than a mention, as the world's first geodesic dome was designed by Bauersfeld in 1922. A lightweight framework of steel was constructed on the roof of the Carl Zeiss Optical Works in Jena, Germany and covered with ferro cement, all to house the first planetarium projector.

It was, however, Fuller who popularised the dome, as part of his work to improve human shelter worldwide through an application of technology to achieve efficiency and economic advantages. Astounding critics by constructing domes in as little as hours, Fuller's domes now shelter more volume than the work of any other architect, standing atop mountains, sheltering radar stations in the Arctic, and occupying the South Pole.

Nowadays, other notable examples of geodesic domes include the Fantasy Entertainment Complex on Kyosho Isle, Japan, the Tacoma Dome in the USA, and the Superior Dome at Northern Michigan University. In addition to leisure purposes, industry also makes use of geodesic domes at present, including the Union Tank Car Maintenance Facility, at Baton Rouge, contained within a large dome, and the Lehigh Portland Cement Storage Facility. In Mai Liao, Taiwan, however, not one but three geodesic domes help to store plastics at the Formosa Plastics Storage Facility. Bucky, who died in 1983, would have been proud...


1: To illustrate this idea a little more simply, let's make it all flat. Pick a two dimensional shape, say a square. Four sides: doesn't look very much like a circle at all, really. Let's increase the number of sides, making it a pentagon. Still not terribly circle-like. But then a hexagon: six sides. Move up to seven sides, then eight. Notice how, if you have the patience, a twenty-sided shape is looking increasingly circular? How many sides must we reach before, to a casual observer, we might as well be using a pair of compasses instead of drawing all these little, tiny sides? The point being that if we can do this with a two dimensional shape, we can do it with three. The more triangles that cover the surface of our dome, the closer it is to a sphere. A dome with four triangular panels is no dome at all, but one with a few hundred is looking increasingly spherical. Plus it impresses the neighbours...

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