Geodesic Domes History
Since the beginning, mankind's ambition has been to feed, protect and improve itself. The oldest civilizations evolved living in round yurts, igloos and teepees because of a need for strong shelter, the scarcity of building materials, and light weight that took the least effort to transport during migration. Many of the world's oldest and architecturally beautiful buildings in Europe and Asia are arched domes, or buildings with clear span arch entries and halls built strong enough to survive the centuries. Dr. Walter Bauersfeld, using spherical geometry, was first to combine the strongest geometric shape, the triangle, with the sturdy arch in Jena, East Germany in 1922.
Some popular geodesic domes known today are:- Future World Exhibition at Epcot Center in Walt Disney World
- Tacoma Dome in Washington State. At 530' in diameter, it is the largest public geodesic dome covering a football field and stands
- Minneapolis Convention Center expanding to 500,000 sq. ft. under four low profile domes
- America's exhibit at the 1967 World Fair in Montreal, for which the United States commissioned Buckminster Fuller
- Milwaukee's Mitchell Park Conservatory with three geodesic domes sitting on elliptical bases that provide tropical flower gardens year round
- Biosphere desert project in Arizona
- Des Moines Arboretum, a self contained ecosphere
- Los Angeles city housing project with over two dozen domes
- Geodesic jungle gyms in many American city parks
- Thousands of family residences and cabins throughout North America
Geodesic Dome Facts
A sphere is defined as the geometric shape that encloses the most volume with the least surface area. A dome is the safest, strongest and most energy efficient building. It takes less building materials to enclose usable living or working area in a dome than any other shaped structure. Forty feet of wall will enclose a 10 x 10 area measuring 100 sq. ft., while forty feet of wall built in a circle will enclose 127 sq. ft., a 27% increase.
Geodesic domes offer the safest shelter in the most violent weather extremes around the world. In tornadoes and hurricanes, high winds and negative air pressure combine and get under the eves and soffits of conventional housing, then rip the roof off, leaving the occupants exposed. A geodesic dome's aerodynamic shape offers the best above ground protection against winds from any direction, allowing gale force winds to slip past. During an earthquake, a conventional house rocks off its foundation and topples as the earth makes lateral shifts. A dome has an even distribution of weight and a low center of gravity so it moves with the earth. Engineering for incredible snow loads is intrinsic in its design. Insulating efficiently against extreme heat or cold is a direct factor of the exposed surface area, or outside wall area of any building. The vaulted ceiling in its free span interior allows excellent air circulation and heat recovery. You may design geodesic dome walls where you want them, if you want them, as you are unrestricted by bearing walls necessary to hold up a standard roof. There are no limits to interior design creativity.
The key structural unit in a geodesic dome is a four-surfaced pyramid figure called a tetrahedron. The geometric shape on which all geodesic domes are based is a 20-sided polyhedron called an icosahedron. Like the tetrahedron, each side is an equilateral triangle, and at each point five triangles meet to form pentagons. Unless it is a complete sphere, all geodesic domes have six pentagons, one at the top and five around the perimeter. The largest domes, hundreds of feet in diameter, have thousands of hexagons but still only six pentagons.
There are three ways to identify a geodesic dome; diameter, frequency and profile. The diameter is the distance from one side of the sphere to the other through the center point. The frequency is the number of framing members, called chords, from the center of any pentagon to the center of any other pentagon. Typically, a dome building is flat on the bottom so it will sit flat on the ground, and the profile is a percentage of sphere, expressed as a fraction. An example: The Imagination Room geodesic dome displayed at the Science Museum of Minnesota is a three frequency, 36' diameter, 4/9ths sphere.
