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Encyclopedia > Geodesic dome
Spaceship Earth in Epcot Center at Walt Disney World is perhaps one of the most famous examples of a large scale geodesic sphere.

The design of the geodesic dome is a complicated matter. In part, this is because there is no one standard design. Rather, there are a number of designs based on taking a Platonic solid, such as an icosahedron, and then projecting each face onto the interior surface of the sphere. There is no perfect way to do this, as neither the angles nor the sides can be preserved without one distorting the other. The result of the design compromise is a regular pattern of triangles with their vertices lying approximately on the surface of the sphere. The edges of the triangles create "geodesics," great circles of a sphere, to distribute stress across the sphere. (The use of patterns of triangles to approximate either a rougher or smoother shape is also fundamental to computer graphics.) In geometry, a Platonic solid is a convex regular polyhedron. ... [Etymology: 16th century: from Greek eikosaedron, from eikosi twenty + -edron -hedron], icosahedral adjective An icosahedron noun (plural: -drons, -dra ) is any polyhedron having 20 faces, but usually a regular icosahedron is implied, which has equilateral triangles as faces. ... For the journal by ACM SIGGRAPH, see Computer Graphics (Publication). ...

Geodesic designs can be extended to any curved, enclosed space, although very oddly-shaped designs would require calculating (and fabricating) each strut individually, and thus be expensive and complicated to construct. Because of the expense and complexity of design and fabrication of any geodesic dome, builders have tended to standardize on a few basic designs.

The principle of building strong stable structures out of patterns of reinforcing triangles, called tensegrity, is most commonly seen in tent design. It has been applied in the abstract in other industrial design, but even in management science and deliberative structures as a conceptual metaphor, especially in the work of Stafford Beer, whose syntegration method is based so specifically on dome design that only fixed numbers of persons can take part in the process at each deliberation stage. In mechanics and biomechanics, tensegrity or tensional integrity is a property of objects with components that use tension and compression in a combination that yields strength and resilience beyond the sum of their components. ... This article does not cite any references or sources. ... To meet Wikipedias quality standards, this article may require cleanup. ... Management science, or MS, is the discipline of using mathematics, and other analytical methods, to help make better business decisions. ... Conceptual metaphor: In cognitive linguistics, metaphor is defined as understanding one conceptual domain in terms of another conceptual domain; for example, using one persons life experience to understand a different persons experience. ... Anthony Stafford Beer (September 25, 1926 - August 23, 2002) was a theorist in operational research and management cybernetics. ...

History

The Montreal Biosphère, formerly the American Pavilion of Expo 67, by R. Buckminster Fuller, on Île Sainte-Hélène, Montreal, Canada

The geodesic dome appealed to Fuller because it was extremely strong for its weight, its "omnitriangulated" surface provided an inherently stable structure, and because a sphere encloses the greatest volume for the least surface area. Fuller had hopes that the geodesic dome would help address the postwar housing crisis. This was in line with his prior hopes for both versions of the Dymaxion House. Dymaxion House as installed in Henry Ford Museum The Dymaxion House was developed by inventor Buckminster Fuller to address several failures he perceived with extant homebuilding techniques. ...

The Climatron greenhouse at Missouri Botanical Gardens, built in 1960, inspired the domes in the science fiction film Silent Running.

From an engineering perspective, geodesic domes are far superior to traditional right-angle post-and-beam constructions. Traditional constructions are a far less efficient use of materials, are far heavier, are less stable, and rely on gravity to stand up. Download high resolution version (2816x2120, 1523 KB)The Climatron at the Missouri Botanical Gardens in Saint Louis, Missouri. ... Download high resolution version (2816x2120, 1523 KB)The Climatron at the Missouri Botanical Gardens in Saint Louis, Missouri. ... Categories: US geography stubs | Botanical gardens | Missouri landmarks | Saint Louis, Missouri ... For other uses, see Silent Running (disambiguation). ...

However, there are some notable drawbacks to geodesic constructions as well. Although extremely strong, domes react to external stresses in ways that confound traditional engineering. Some tensegrity structures will retain their shape and contract evenly when stressed on the outside and some do not. For example, when a dome built at Princeton, New Jersey was hit by a snowplow, the stress was transmitted through the structure and popped out struts on the opposite side. The behavior of tension and compression forces in the different varieties of geodesic structures is still not well understood, so traditionally trained structural engineers may not be able to adequately predict their performance and safety. In mechanics and biomechanics, tensegrity or tensional integrity is a property of objects with components that use tension and compression in a combination that yields strength and resilience beyond the sum of their components. ... Nassau Street, Princetons main street. ...

The dome was successfully adopted for specialized industrial use, such as the 1958 Union Tank Car Company dome near Baton Rouge, Louisiana and specialty buildings like the Henry Kaiser dome, auditoriums, weather observatories, and storage facilities. The dome was soon breaking records for covered surface, enclosed volume, and construction speed. Nickname: Motto: Authentic Louisiana at every turn Location of Baton Rouge in East Baton Rouge Parish, Louisiana Coordinates: , Country United States State Louisiana Parish East Baton Rouge Parish Founded 1699 Incorporated 16 January 1817 Government  - Mayor Melvin Kip Holden (D) Area  - City  79. ... Henry Kaiser is: An industrialist involved with the construction of Boulder (now Hoover) Dam, see Henry J. Kaiser; A musician&#8212;see Henry Kaiser (musician). ...

Leveraging the geodesic dome's stability, the US Air Force experimented with helicopter-deliverable units. The dome was introduced to a wider audience at Expo 67 the Montreal, Canada World's Fair as part of the American Pavilion. The structure's covering later burned, but the structure itself still stands and, under the name Biosphère, currently houses an interpretive museum about the Saint Lawrence River. The 1967 International and Universal Exposition, or simply Expo 67 was the General Exhibition Category 1 Worlds Fair held in Montreal, Quebec, Canada from April 27 to October 29, 1967. ... This article needs cleanup. ... Worlds Fair is any of various large expositions held since the mid-19th century. ... The BiosphÃ¨re is a geodesic dome on Ile Sainte-HÃ©lÃ¨ne in MontrÃ©al, Canada. ... The Louvre Museum in Paris, one of the largest and most famous museums in the world. ... TheSaint Lawrence River (In French: fleuve Saint-Laurent) is a large west-to-east flowing river in the middle latitudes of North America, connecting the Great Lakes with the Atlantic Ocean. ...

In the 1970s the Cinesphere dome was built at the Ontario Place amusement park in Toronto, Canada. In 1975, a dome was constructed at the South Pole, where its resistance to snow and wind loads is important. The 1970s decade refers to the years from 1970 to 1979, also called The Seventies. ... Cinesphere is the worlds first permanent IMAX theatre, built in 1971. ... Ontario Place is a multiple use entertainment and seasonal amusement park owned by the Province of Ontario. ... The Amundsen-Scott South Pole Station is a U.S. research station at the South Pole, in Antarctica. ...

Residential domes have been less successful, due largely to their complexity and consequent higher construction costs. Fuller himself lived in a geodesic dome in Carbondale, Illinois, at the corner of Forest and Cherry. Residential domes have so far not caught on to the extent that Fuller hoped. He envisioned residential domes as air-deliverable products manufactured by an aerospace-like industry. Fuller's dome home still exists, and a group called RBF Dome NFP is attempting to restore the dome and have it registered as a National Historic Landmark. , Carbondale is a city in Southern Illinois in the midwest United States, about one hour north of Cairo. ...

Chord factors

A "chord" is a line segment lying on the surface of a circle or sphere. The chord factor of a dome indicates the number of times the "polyhedral face" is being subdivided when it is being projected onto the interior surface of the sphere. In this context, it is symbolized by "v."

The chord in a dome is calculated as twice the sine of half the "central angle of the chord" (the central angle of the chord is the angle between the center point inside the sphere and the ends of the chord). Determining the central angle usually requires some non-trivial spherical geometry. Spherical geometry is the geometry of the two-dimensional surface of a sphere. ...

In Geodesic Math and How to Use It Hugh Kenner writes, "Tables of chord factors, containing as they do the essential design information for spherical systems, were for many years guarded like military secrets. As late as 1966, some 3v icosa figures from Popular Science Monthly were all anyone outside the circle of Fuller licensees had to go on." (page 57, 1976 edition) Hugh Kenner (January 7, 1923 â€“ November 24, 2003), Canadian literary scholar, critic, & professor. ... Issue of Popular Science Popular Science is an American monthly magazine founded in 1872 carrying articles for the general reader on science and technology subjects. ...

Other tables became available with publication of Lloyd Kahn's Domebook 1 (1970) and Domebook 2 (1971). With advent of personal computers, the mathematics became more accessible. Rick Bono's Dome software, outputs a script that can be used with the POV-ray raytracer to produce 3D pictures of domes. Domes based on differing polyhedrals and differing chord factors produce differing results. The Persistence of Vision Raytracer, or POV-Ray, is a ray tracing program available for a variety of computer platforms. ... A ray traced scene. ...

Firstly, of course, like all domes, geodesic domes provide an enclosed space free of structural supports. Domes are very strong, actually getting stronger as they get larger. The basic structure can be erected very quickly from lightweight pieces by a small crew. Domes as large as fifty meters have been constructed in the wilderness from rough materials without a crane. The dome is also aerodynamic, so it withstands considerable wind loads, such as those created by hurricanes. Solar heating is possible by placing an arc of windows across the dome: the more heating needed, the wider the arc should be, to encompass more of the year. This article is about weather phenomena. ...

Today there are many companies that sell both dome plans and frame material with instructions designed simply enough for owners to build themselves, and many do to make the net cost lower than standard construction homes. Construction techniques have improved based on real world feedback over sixty years and many newer dome homes can resolve nearly all of the disadvantages below that were more true of the early dome homes.

As a housing system the dome can have numerous drawbacks and problems:

The shape of a dome house makes it difficult to conform to code requirements for placement of sewer vents and chimneys. Off-the-shelf building materials (e.g., plywood, strand board) normally come in rectangular shapes; there can be considerably more scrap, left from cutting rectangles down to triangles, than with a conventional building approach, thus driving costs up. Fire escapes are problematic; codes require them for larger structures, and they are expensive. Windows conforming to code can cost anywhere from five to fifteen times as much as windows in conventional houses. Professional electrical wiring costs more because of increased labor time. However, even owner-wired situations are costly, because more of certain materials are required for dome construction.

Air stratification and moisture distribution within a dome are unusual, and these conditions tend to quickly degrade wooden framing or interior paneling. Privacy is difficult to guarantee because a dome is difficult to partition satisfactorily. Sounds, smells, and even reflected light tend to be conveyed through the entire structure.

As with any sloping shape, the dome produces wall areas that can be difficult to use and leaves some peripheral floor area with restricted use due to lack of headroom. This can leave a volume that may require heating – representing a cost in energy – but that cannot be lived in. Circular plan shapes lack the simple modularity provided by rectangles. Furnishers and fitters usually design with flat surfaces in mind, and so placing a standard sofa (for example) results in a half-moon behind the sofa being wasted. This is best overcome by purpose-built fittings, though it adds to cost.

Dome builders using cut-board sheathing materials find it hard to seal domes against rain, because of their many seams; as well, these seams may be stressed because ordinary solar heat flexes the entire structure each day as the sun moves across the sky.

The most effective waterproofing method with a wooden dome is to shingle the dome. One-piece reinforced concrete or plastic domes are also in use, and some domes have been constructed from plastic or waxed cardboard triangles that are overlapped in such a way as to shed water. Buckminster Fuller's former student J. Baldwin states that there is no reason for a properly designed, well-constructed dome to leak, and that some designs cannot leak (Bucky Works: Buckminster Fuller's Ideas for Today). However, Lloyd Kahn, after writing two books on the subject (Domebook One and Domebook 2), became disillusioned with domes. He calls domes "smart but not wise" on his website, and has collected many of the criticisms given above. Look up shingle in Wiktionary, the free dictionary. ... James Tennant Baldwin (whose books and articles have been published under the names J. Baldwin, Jay Baldwin, and James T. Baldwin) is an American industrial designer and writer born in 1934. ... Lloyd Kahn at a 2004 booksigning Lloyd Kahn (b. ...

Methods of construction

Construction details of a permanently installed tent-type geodesic dome by Buckminster Fuller.

Temporary greenhouse domes have been constructed by stapling plastic sheeting onto a dome constructed from one-inch square beams. The result is warm, movable by hand in sizes less than 20 feet, and cheap. It should be staked to the ground to prevent it being moved by wind.

Steel-framework domes can be easily constructed of electrical conduit. One flattens the end of a strut and drills bolt holes at the needed length. A single bolt secures a vertex of struts. The nuts are usually set with removable locking compound, or if the dome is portable, have a castle nut with a cotter pin. This is the standard way to construct domes for jungle-gyms.

Concrete and foam plastic domes generally start with a steel framework dome, wrapped with chicken wire and wire screen for reinforcement. The chicken wire and screen is tied to the framework with wire ties. A coat of material is then sprayed or molded onto the frame. Tests should be performed with small squares to achieve the correct consistency of concrete or plastic. Generally, several coats are necessary on the inside and outside. The last step is to saturate concrete or polyester domes with a thin layer of epoxy compound to shed water.

Some concrete domes have been constructed from prefabricated, prestressed, steel-reinforced concrete panels that can be bolted into place. The bolts are within raised receptacles covered with little concrete caps to shed water. The triangles overlap to shed water. The triangles in this method can be molded in forms patterned in sand with wooden patterns, but the concrete triangles are usually so heavy that they must be placed with a crane. This construction is well-suited to domes because there is no place for water to pool on the concrete and leak through. The metal fasteners, joints and internal steel frames remain dry, preventing frost and corrosion damage. The concrete resists sun and weathering. Some form of internal flashing or caulking must be placed over the joints to prevent drafts. The 1963 Cinerama Dome was built from precast concrete hexagons and pentagons. The Cinerama Dome, as decorated for Shrek 2 Pacific Theatres Cinerama Dome at 6360 Sunset Boulevard in Hollywood of the United States has been a landmark movie theater since its opening on November 7, 1963. ... Precast concrete is an ancient type of construction material made with concrete cast in a reusable mold or form and cured in a controlled environment, then transported to the construction site and lifted into place. ...

Largest geodesic dome structures

Many geodesic domes built are still in use. According to the Buckminster Fuller Institute Web site, the largest geodesic-dome structures (listed in descending order from largest diameter) are:

Concrete domes have been used in building construction for millennia. ... Cloud nines are airborne habitats first proposed by Buckminster Fuller. ... The domed city is a kind of space habitat that appears repeatedly in science fiction. ... The Icosahedral Fullerene C540 C60, C-60 and Buckyballs redirect here. ... A Hoberman Sphere is a structure that resembles a geodesic dome, but is capable of folding down to a fraction of its normal size by the scissor-like action of its joints. ... A monolithic dome is a structure built from polyurethane foam, rebar and concrete. ... Radomes at the Misawa Security Operations Center, Misawa, Japan. ... For other uses, see Silent Running (disambiguation). ... Simplified space frame roof with the half-octahedron highlighted in blue A space frame is a truss-like, lightweight rigid structure constructed from interlocking struts in a geometric pattern. ... Stepan Center is Notre Dames multi-purpose facility. ... The worlds first double curvature lattice steel Shell by V.G.Shukhov (during construction), Vyksa near Nizhny Novgorod, 1897 Thin-shell structures can be defined as curved structures capable of transmitting loads in more than two directions to supports. ... In architecture and structural engineering, a truss is a structure comprising one or more triangular units which are constructed with straight slender members whose ends are connected at joints. ...

Results from FactBites:

 Geodesic dome - Wikipedia, the free encyclopedia (2529 words) A geodesic dome (IPA: /ʤiədɛsɪk/ or /ʤiədizɪk/ /dəʊm/) is an almost spherical structure based on a network of struts arranged on great circles (geodesics) lying approximately on the surface of a sphere. The geodesic dome appealed to Fuller because it was extremely strong for its weight, its "omnitriangulated" surface provided an inherently stable structure, and because a sphere encloses the greatest volume for the least surface area. In this context, it is symbolized by "v." The chord in a dome is calculated as twice the sine of half the "central angle of the chord" (the central angle of the chord is the angle between the center point inside the sphere and the ends of the chord).
 Geodesic - Wikipedia, the free encyclopedia (1288 words) Geodesics are defined to be (locally) the shortest path between points on the space. The term "geodesic" comes from geodesy, the science of measuring the size and shape of Earth; in the original sense, a geodesic was the shortest route between two points on the Earth's surface, namely, a segment of a great circle. In physics, geodesics describe the motion of point particles; in particular, the path taken by a falling rock, an orbiting satellite, or the shape of a planetary orbit are all described by geodesics in the theory of general relativity.
More results at FactBites »

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