Geodesic dome (redirected from Geodesic structures)

geodesic dome (jē'ədĕs`ĭk, –dē`sĭk), structure that roughly approximates a hemisphere. Popular in recent years as economical, easily erected buildings, geodesic domes are geometrically determined from a model and may be constructed from limited materials. The architect Buckminster Fuller was an early proponent of geodesics for housing and other functions. Among the best-known examples of geodesic domes have been the United States Pavilion at Montreal's Expo 67 and Biosphere II, an experimental recreation of the ecosystem in Arizona.

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Geodesic dome

A curved lattice grid dome that utilizes the equilateral triangle as the basis of its surface grid geometry. R. Buckminster Fuller, the inventor and champion of the geodesic dome, obtained a patent in 1954 that described a method of dividing a spherical surface into equilateral triangles. The two regular polyhedra that can be inscribed in a sphere are the dodecahedron (12 faces, each of which is a regular polygon; illus. a) and the more utilized icosahedron (20 faces, each of which is an equilateral triangle; illus. b).

The geodesic dome has been used for everything from great exhibition spaces and halls to outdoor tent supports and jungle gyms. By utilizing the icosahedron as the basic building block of the geodesic dome, larger domes are possible with additional triangular subdivisions. This subdivision is known as the frequency. The first frequency is to interconnect the projected midpoints of the struts of each equilateral triangle of the icosahedron as they will project on the spherical surface. The result is four almost equilateral triangles where there was one before. The resulting lattice has similar but not exactly equilateral triangles if the grid is to remain on the spherical surface. This subdivision process can continue. The resulting grids have both triangular and hexagonal grids as a by-product within the basic geodesic dome geometry, with pentagons around the apex of the basic underlying icosahedron framework (illus. c).