Tensegrity
Encyclopedia
- For the movement system created by Carlos CastanedaCarlos CastanedaCarlos Castaneda was a Peruvian-born American anthropologist and author....
, see Tensegrity (Castaneda)Tensegrity (Castaneda)Tensegrity was a term used by Carlos Castaneda to refer to some movements called magical passes that he said were developed by Native American shamans who lived in Mexico in times prior to the Spanish conquest.-Cleargreen Inc and Tensegrity:Castaneda and the other students of Don Juan created...
Tensegrity, tensional integrity or floating compression, is a structural principle based on the use of isolated components in compression inside a net of continuous tension
Tension (mechanics)
In physics, tension is the magnitude of the pulling force exerted by a string, cable, chain, or similar object on another object. It is the opposite of compression. As tension is the magnitude of a force, it is measured in newtons and is always measured parallel to the string on which it applies...
, in such a way that the compressed members (usually bars or struts) do not touch each other and the prestressed tensioned members (usually cables or tendons) delineate the system spatially.
The term tensegrity was coined by Buckminster Fuller
Buckminster Fuller
Richard Buckminster “Bucky” Fuller was an American systems theorist, author, designer, inventor, futurist and second president of Mensa International, the high IQ society....
as a contraction of tensional integrity. The other denomination of tensegrity, floating compression, was used mainly by Kenneth Snelson
Kenneth Snelson
Kenneth Snelson is a contemporary sculptor and photographer. His sculptural works are composed of flexible and rigid components arranged according to the idea of 'tensegrity', although Snelson does not use the term....
.
Concept
- loading members only in pure compression or pure tension, meaning the structure will only fail if the cables yield or the rods buckle
- preloadPreloadIn cardiac physiology, preload is the end volumetric pressure that stretches the right or left ventricle of the heart to its greatest geometric dimensions under variable physiologic demand...
or tensional prestressPrestressed structurePrestressed structure is the one whose overall integrity, stability and security depend, primarily, on a prestressing. Prestressing means the intentional creation of permanent stresses in a structure for the purpose of improving its performance under various service conditions.There are the...
, which allows cables to be rigid in tension - mechanical stability, which allows the members to remain in tension/compression as stress on the structure increases
Because of these patterns, no structural member experiences a bending moment
Bending Moment
A bending moment exists in a structural element when a moment is applied to the element so that the element bends. Moments and torques are measured as a force multiplied by a distance so they have as unit newton-metres , or pound-foot or foot-pound...
. This can produce exceptionally rigid structures for their mass and for the cross section of the components.
A conceptual building block of tensegrity is seen in the 1951 Skylon tower
Skylon (tower)
The Skylon was a futuristic-looking, slender, vertical, cigar-shaped steel tensegrity structure located by the Thames in London, that apparently floated above the ground, built in 1951 for the Festival of Britain....
. Six cable
Wire rope
thumb|Steel wire rope Wire rope is a type of rope which consists of several strands of metal wire laid into a helix. Initially wrought iron wires were used, but today steel is the main material used for wire ropes....
s, three at each end, hold the tower in position. We say the three cables connected to the bottom "define" its location. The other three cables are simply keeping it vertical.
A three-rod tensegrity structure (shown) builds on this: the ends of each rod look like the bottom of the Skylon tower. As long as the angle between any two cables is smaller than 180°, the position of the rod is well defined. There are also three connection points defining the position the rod tops. This makes the overall structure stable. Variations such as Needle Tower
Needle Tower
Needle Tower is a public artwork by American sculptor Kenneth Snelson located outside of the Hirshhorn Museum and Sculpture Garden in Washington, DC, United States.-Description:...
involve more than three cables meeting at the end of a rod, but these can be thought of as three cables defining the position of that rod end with the additional cables simply attached to that well-defined
Well-defined
In mathematics, well-definition is a mathematical or logical definition of a certain concept or object which uses a set of base axioms in an entirely unambiguous way and satisfies the properties it is required to satisfy. Usually definitions are stated unambiguously, and it is clear they satisfy...
point
Point (geometry)
In geometry, topology and related branches of mathematics a spatial point is a primitive notion upon which other concepts may be defined. In geometry, points are zero-dimensional; i.e., they do not have volume, area, length, or any other higher-dimensional analogue. In branches of mathematics...
in space.
Eleanor Hartley points out visual transparency as an important aesthetic quality of these structures. Korkmaz et al put forward that the concept of tensegrity is suitable for adaptive architecture thanks to lightweight characteristics.
Applications
The idea was adopted into architecture in 1960s when Maciej Gintowt and Maciej Krasiński, architects of SpodekSpodek
Spodek is a multipurpose arena complex in Katowice, Poland, opened in 1971 at 35 Korfanty Street under the name Wojewódzka Hala Widowiskowo-Sportowa w Katowicach , under which it is known in the Polish technical/architectural literature, and under which it formally functioned until 1997.Aside from...
a venue in Katowice
Katowice
Katowice is a city in Silesia in southern Poland, on the Kłodnica and Rawa rivers . Katowice is located in the Silesian Highlands, about north of the Silesian Beskids and about southeast of the Sudetes Mountains.It is the central district of the Upper Silesian Metropolis, with a population of 2...
, Poland
Poland
Poland , officially the Republic of Poland , is a country in Central Europe bordered by Germany to the west; the Czech Republic and Slovakia to the south; Ukraine, Belarus and Lithuania to the east; and the Baltic Sea and Kaliningrad Oblast, a Russian exclave, to the north...
, designed it as one of the first major structures to employ the principle of tensegrity. The roof uses an inclined surface held in check by a system of cables holding up its circumference.
In the 1980s David Geiger designed Seoul Olympic Gymnastics Arena
Olympic Gymnastics Arena
The Olympic Gymnastics Arena is an indoor sports arena, located at the Olympic Park, in Seoul, South Korea. The capacity of the arena is 14,730 and was constructed between 31 August 1984 and 30 April 1986, to host gymnastics at the 1988 Summer Olympics....
for the 1988 Summer Olympics
1988 Summer Olympics
The 1988 Summer Olympics, officially known as the Games of the XXIV Olympiad, were an all international multi-sport events celebrated from September 17 to October 2, 1988 in Seoul, South Korea. They were the second summer Olympic Games to be held in Asia and the first since the 1964 Summer Olympics...
. The Georgia Dome
Georgia Dome
The Georgia Dome is a domed stadium located in Atlanta, Georgia, United States, between downtown to the east and Vine City to the west. It is primarily the home stadium for the NFL Atlanta Falcons and the NCAA Division I FCS Georgia State Panthers football team. It is owned and operated by the...
, which was used for the 1996 Summer Olympics
1996 Summer Olympics
The 1996 Summer Olympics of Atlanta, officially known as the Games of the XXVI Olympiad and unofficially known as the Centennial Olympics, was an international multi-sport event which was celebrated in 1996 in Atlanta, Georgia, United States....
is a large tensegrity structure of similar design to the aforementioned Gymnastics Hall.
Shorter columns or struts in compression are stronger than longer ones. This in turn led some, namely Fuller
Buckminster Fuller
Richard Buckminster “Bucky” Fuller was an American systems theorist, author, designer, inventor, futurist and second president of Mensa International, the high IQ society....
, to make claims that tensegrity structures could be scaled up to to cover whole cities. However, Kenneth Snelson
Kenneth Snelson
Kenneth Snelson is a contemporary sculptor and photographer. His sculptural works are composed of flexible and rigid components arranged according to the idea of 'tensegrity', although Snelson does not use the term....
describes the claims as "nonsense. Short compression struts mean long tension lines which mean extreme elasticity
Elasticity
Elasticity may refer to:*Elasticity , continuum mechanics of bodies that deform reversibly under stressNumerous uses are derived from this physical sense of the term, which is inherently mathematical, such as used in Engineering, Chemistry, Construction and variously in Economics:*Elasticity , the...
." Snelson also casts doubt on what many now claim to be examples of tensegrity structures such as the Georgia Dome
Georgia Dome
The Georgia Dome is a domed stadium located in Atlanta, Georgia, United States, between downtown to the east and Vine City to the west. It is primarily the home stadium for the NFL Atlanta Falcons and the NCAA Division I FCS Georgia State Panthers football team. It is owned and operated by the...
that he says is more like a "beautifully designed giant bicycle wheel". The heart of the problem according to Snelson is "tensegrity works the way it does because it is an equilibrium of contesting forces within a closed system. But the forces within the system need to be so huge that
the structure becomes inefficient for supporting any external loads."
Tensegrity is a contraction of tensional integrity structuring. All geodesic domes are tensegrity structures, whether the tension-islanded compression differentiations are visible to the observer or not. Tensegrity geodesic spheres do what they do because they have the properties of hydraulically or pneumatically inflated structures.
As Harvard physician and scientist Donald E. Ingber
Donald E. Ingber
Donald E. Ingber, is an American cell biologist, Founding Director of the Wyss Institute for Biologically Inspired Engineering at Harvard University, the Judah Folkman Professor of Vascular Biology at Harvard Medical School and Children's Hospital Boston, and Professor of Bioengineering at the...
explains:
The tension-bearing members in these structures — whether Fuller's domes or Snelson's sculptures — map out the shortest paths between adjacent members (and are therefore, by definition, arranged geodesically) Tensional forces naturally transmit themselves over the shortest distance between two points, so the members of a tensegrity structure are precisely positioned to best withstand stress. For this reason, tensegrity structures offer a maximum amount of strength.
On 4 October 2009, the Kurilpa Bridge opened across the Brisbane River
Brisbane River
The Brisbane River is the longest river in south east Queensland, Australia, and flows through the city of Brisbane, before emptying into Moreton Bay. John Oxley was the first European to explore the river who named it after the Governor of New South Wales, Thomas Brisbane in 1823...
in Queensland, Australia. The bridge is a multiple-mast, cable-stay structure based on the principles of tensegrity. It is also the largest tensegrity structure in existence.
Biology
Biotensegrity, a term coined by Dr Stephen Levin, is the application of tensegrity principles to biologic structures. Biological structures such as muscleMuscle
Muscle is a contractile tissue of animals and is derived from the mesodermal layer of embryonic germ cells. Muscle cells contain contractile filaments that move past each other and change the size of the cell. They are classified as skeletal, cardiac, or smooth muscles. Their function is to...
s, bones
Skeleton
The skeleton is the body part that forms the supporting structure of an organism. There are two different skeletal types: the exoskeleton, which is the stable outer shell of an organism, and the endoskeleton, which forms the support structure inside the body.In a figurative sense, skeleton can...
, fascia
Fascia
A fascia is a layer of fibrous tissue that permeates the human body. A fascia is a connective tissue that surrounds muscles, groups of muscles, blood vessels, and nerves, binding those structures together in much the same manner as plastic wrap can be used to hold the contents of sandwiches...
, ligaments and tendons, or rigid and elastic cell membrane
Cell membrane
The cell membrane or plasma membrane is a biological membrane that separates the interior of all cells from the outside environment. The cell membrane is selectively permeable to ions and organic molecules and controls the movement of substances in and out of cells. It basically protects the cell...
s, are made strong by the unison of tensioned and compressed parts. The muscular-skeletal system is a synergy of muscle and bone. The muscles and connective tissues provide continuous pull and the bones discontinuous push.
Tensegrity in molecular biology
Molecular biology
Molecular biology is the branch of biology that deals with the molecular basis of biological activity. This field overlaps with other areas of biology and chemistry, particularly genetics and biochemistry...
has been developed by Donald Ingber
Donald E. Ingber
Donald E. Ingber, is an American cell biologist, Founding Director of the Wyss Institute for Biologically Inspired Engineering at Harvard University, the Judah Folkman Professor of Vascular Biology at Harvard Medical School and Children's Hospital Boston, and Professor of Bioengineering at the...
.
Politics
The concept of tensegrity structures as a metaphor for political self supporting structures in particular those related to corruption or 'hold over' effects, has been used by Senator Stuart SyvretStuart Syvret
Stuart Syvret is a political activist in Jersey. He held elected office as a member of the States of Jersey assembly from 1990 to 2010. From 1999 to 2007, Svyret had executive responsibilities first as President of the Health and Social Services Committee and, after the 2005 constitutional reforms,...
(States of Jersey) to explain the persistence and ultimately weakness of such structures. Senator Syvret is quoted as saying 'I can sense a very large pair of bolt-croppers beginning to approach the cables of the Jersey corruption tensegrity structure'.
History
Artist
An artist is a person engaged in one or more of any of a broad spectrum of activities related to creating art, practicing the arts and/or demonstrating an art. The common usage in both everyday speech and academic discourse is a practitioner in the visual arts only...
Kenneth Snelson
Kenneth Snelson
Kenneth Snelson is a contemporary sculptor and photographer. His sculptural works are composed of flexible and rigid components arranged according to the idea of 'tensegrity', although Snelson does not use the term....
produced his innovative 'X-Piece' after artistic explorations at Black Mountain College
Black Mountain College
Black Mountain College, a school founded in 1933 in Black Mountain, North Carolina, was a new kind of college in the United States in which the study of art was seen to be central to a liberal arts education, and in which John Dewey's principles of education played a major role...
(where Buckminster Fuller
Buckminster Fuller
Richard Buckminster “Bucky” Fuller was an American systems theorist, author, designer, inventor, futurist and second president of Mensa International, the high IQ society....
was lecturing) and elsewhere. Some years later, the term 'tensegrity' was coined by Fuller, who is best known for his geodesic dome
Geodesic dome
A geodesic dome is a spherical or partial-spherical shell structure or lattice shell based on a network of great circles on the surface of a sphere. The geodesics intersect to form triangular elements that have local triangular rigidity and also distribute the stress across the structure. When...
s. Throughout his career, Fuller had experimented incorporating tensile components in his work, such as in the framing of his dymaxion houses.
Snelson's 1948 innovation spurred Fuller to immediately commission a mast from Snelson. In 1949, Fuller developed an icosahedron
Icosahedron
In geometry, an icosahedron is a regular polyhedron with 20 identical equilateral triangular faces, 30 edges and 12 vertices. It is one of the five Platonic solids....
based on the technology, and he and his students quickly developed further structures and applied the technology to building domes. After a hiatus, Snelson also went on to produce a plethora of sculpture
Sculpture
Sculpture is three-dimensional artwork created by shaping or combining hard materials—typically stone such as marble—or metal, glass, or wood. Softer materials can also be used, such as clay, textiles, plastics, polymers and softer metals...
s based on tensegrity concepts. Snelson's main body of work began in 1959 when a pivotal exhibition at the Museum of Modern Art
Museum of Modern Art
The Museum of Modern Art is an art museum in Midtown Manhattan in New York City, on 53rd Street, between Fifth and Sixth Avenues. It has been important in developing and collecting modernist art, and is often identified as the most influential museum of modern art in the world...
took place. At the MOMA exhibition, Fuller had shown the mast and some of his other work.
At this exhibition, Snelson, after a discussion with Fuller and the exhibition organizers regarding credit for the mast, also displayed some work in a vitrine
Display case
A display case is a cabinet with one or often more transparent glass sides and/or top, used to display objects for viewing, for example in an exhibition, museum, house, in retail, or a restaurant. Often labels are included with the displayed objects, providing information...
.
Snelson's best known piece is his 18-meter-high Needle Tower
Needle Tower
Needle Tower is a public artwork by American sculptor Kenneth Snelson located outside of the Hirshhorn Museum and Sculpture Garden in Washington, DC, United States.-Description:...
of 1968.
Russian artist Viatcheslav Koleichuk claimed that the idea of tensegrity was invented first by Karl Ioganson, Russian artist of Latvian descent, who contributed some works to the main exhibition of Russian constructivism
Constructivism (art)
Constructivism was an artistic and architectural philosophy that originated in Russia beginning in 1919, which was a rejection of the idea of autonomous art. The movement was in favour of art as a practice for social purposes. Constructivism had a great effect on modern art movements of the 20th...
in 1921. Koleichuk's claim was backed up by Maria Gough for one of the works at the 1921 constructivist exhibition. Kenneth Snelson however denied this claim insisting that Ioganson's work was much further than one step from his own concept of tensegrity,
but he has acknowledged the constructivists as an influence for his work. French engineer David Georges Emmerich has also noted how Ioganson's work seemed to foresee tensegrity concepts.
See also
- Tensile structureTensile structureA tensile structure is a construction of elements carrying only tension and no compression or bending. The term tensile should not be confused with tensegrity, which is a structural form with both tension and compression elements....
- TensairityTensairityTensairity is a registered mark. Circle R. Tensairity is a foundational structure using inflated airbeams and attached stiffeners or cables that gains mechanical advantages for low mass. Pneumatic structures using tensairty are solving problems....
- Hyperboloid structureHyperboloid structureHyperboloid structures are architectural structures designed with hyperboloid geometry. Often these are tall structures such as towers where the hyperboloid geometry's structural strength is used to support an object high off the ground, but hyperboloid geometry is also often used for decorative...
- Thin-shell structureThin-shell structureThin-shell structures are light weight constructions using shell elements. These elements are typically curved and are assembled to large structures...
- SkylonSkylon (tower)The Skylon was a futuristic-looking, slender, vertical, cigar-shaped steel tensegrity structure located by the Thames in London, that apparently floated above the ground, built in 1951 for the Festival of Britain....
- Cloud nine (Tensegrity sphere)Cloud nine (Tensegrity sphere)Cloud nine is the name Buckminster Fuller gave to his proposed airborne habitats created from giant geodesic spheres, which might be made to levitate by slightly heating the air inside above the ambient temperature....
- Saddle roofSaddle roofA saddle roof is one which follows a convex curve about one axis and a concave curve about the other. The hyperbolic paraboloid form has been used for roofs at various times since it is easily constructed from straight sections of lumber, steel, or other conventional materials...
- Pask's prismatic tensegrity model of a concept in any medium
- SynergeticsSynergetics (Fuller)Synergetics is the empirical study of systems in transformation, with an emphasis on total system behavior unpredicted by the behavior of any isolated components, including humanity’s role as both participant and observer....
- PrestressPrestressed structurePrestressed structure is the one whose overall integrity, stability and security depend, primarily, on a prestressing. Prestressing means the intentional creation of permanent stresses in a structure for the purpose of improving its performance under various service conditions.There are the...
External links
- Scientific Publications in the Field of Tensegrity by Swiss Federal Institute of Technology (EPFL), Applied Computing and Mechanics Laboratory (IMAC)
- Valentin Gomez-Jauregui's site Very interesting web page (in English and Spanish) showing images, references and explanations about tensegrity.
- Valentin Gomez-Jauregui's thesis Complete and useful thesis (in English) showing Tensegrity Structures and their application to architecture, with images, references and explanations about tensegrity.
- Kenneth Snelson's site with an excellent article on the theory and development of tensegrity as well as pictures of his sculptures from desk top pieces to 90 foot towers.
- Kirby Urner's page on Kenneth Snelson, developed in collaboration with the artist before the above official site came on-line, still relevant.
- Dubai Tensegrity Tower designed by Aurel von Richthofen includes diagrams of proposed tower with elevator.
- Ortegrity by Timothy Wilken, MD 2002, 70 page long PDF document describing human interactions in terms of tensegrity.
- Tensegrity in a Cell -- This interactive feature allows you to control a cell's internal structural elements. From Donald Ingber and the research department of Children's Hospital Boston.
- Stephen Levin's Biotensegrity site Several papers on the tensegrity mechanics of biologic structures from viruses to vertebrates by an Orthopedic Surgeon.
- Dynamic Template site: an excellent article by Dr. Lofthouse that demonstrates how spatially-organised flows of aminophospholipids in the red blood cell membrane convert the cell surface into a 'Dynamic Template' for its cortical Spectrin cytoskeleton. This is the only model to date that provides biological cells with a mechanism capable of pre-stressing flexible, membrane-associated protein networks, which is absent from Glanz & Ingbers' exclusively protein based models of cellular 'Tensegrity' structures.
- Tensegrity and spinal manipulations
- Tensegrity examples Several tensegrity examples by Marcelo Pars.
- Tensegrity structures A blog about tensegrity systems in Civil Engineering incl. news, ideas and more!
- Sine Utilitate Examples of contemporary sculptural constructions by Christos Saccopoulos using tensegrity principles.
- Virtual 3D tensegrity structures a nice interactive Java applet simuluating various selectable structures.
Patents
, "Tensile-Integrity Structures", November 13, 1962, Buckminster Fuller.- French Patent No. 1,377,290, "Construction de Reseaux Autotendants", September 28, 1964, David Georges Emmerich.
- French Patent No. 1,377,291, "Structures Linéaires Autotendants", September 28, 1964, David Georges Emmerich., "Suspension Building" (also called aspension), July 7, 1964, Buckminster Fuller., "Continuous Tension, Discontinuous Compression Structure", February 16, 1965, Kenneth Snelson., "Non-symmetrical Tension-Integrity Structures", February 18, 1975, Buckminster Fuller.