A concrete shell, also commonly called thin shell concrete structure, is a structure composed of a relatively thin shell of concrete, usually with no interior columns or exterior buttresses. The shells are most commonly flat plates and domes, by may also take the form of ellipsoids or cylinderical sections, or some combination thereof. The fist concrete shell dates back to the second century. The most common form of concrete consists of Portland cement, construction aggregate (generally gravel and sand) and water. ... Columns redirects here. ... A buttress (and mostly concealed, a flying buttress) supporting walls at the Palace of Westminster Four different types of buttress: diagonal, on the statues plinth; an ordinary buttress supporting a flying buttress, to the right of the statue; a small ordinary buttress to the right side of the picture... This article is about the building structural element. ... 3D rendering of an ellipsoid In mathematics, an ellipsoid is a type of quadric that is a higher dimensional analogue of an ellipse. ... Look up cylinder in Wiktionary, the free dictionary. ... ( 1st century - 2nd century - 3rd century - other centuries) Events Roman Empire governed by the Five Good Emperors ( 96– 180) – Nerva, Trajan, Hadrian, Antoninus Pius, Marcus Aurelius. ...

Uses

Most concrete shell structures are buildings, including storage facilities, commercial buildings, and residential homes. Concrete shell construction techniques are well suited for complex curves, are also used to build boat hulls (called ferroconcrete). Civil engineering students often build concrete canoes during their undergraduate classwork in order to explore the techniques involved in building concrete shells. The canoes are then raced in a competition, and in order to be competitive, the canoes must be both lightweight and strong. A hull is the body or frame of a ship or boat. ... The term civil engineer refers to an individual who practices civil engineering. ... Students attending a lecture at the Helsinki University of Technology The word student is etymologically derived through Middle English from the Latin second-type conjugation verb stŭdērĕ, meaning to direct ones zeal at; hence a student is one who directs zeal at a subject. ... A concrete canoe is the term for a canoe made of concrete, typically created for an engineering competition. ... In some educational systems, undergraduate education is post-secondary education up to the level of a Bachelors degree. ... The examples and perspective in this article or section may not represent a worldwide view. ...

Advantages

Like the arch, the curved shapes often used for concrete shells are naturally strong structures, allowing wide areas to be spanned without the use of internal supports, giving an open, unobstructed interior. The use of concrete as a building material reduces but materials cost and contruction costs, as concrete is relatively inexpensive and easily cast into compound curves. The resulting structure may be immensely strong and safe; modern monolithic dome houses, for example, have resisted hurricanes and fires, and are widely considered to be strong enough to withstand even F5 tornadoes. Isometric view of a typical arch An arch is a curved structure capable of spanning a space while supporting significant weight (e. ... A monolithic dome is a structure built from polyurethane foam, rebar and concrete. ... This article is about weather phenomena. ... A tornado in central Oklahoma. ...

Disadvantages

Since concrete is a porous material, concrete domes often have issues with sealing. If not treated, rainwater can seep through the roof and leak into the interior of the building. On the other hand, the seamless construction of concrete domes prevents air from escaping, and can lead to buildup of condensation on the inside of the shell. Shingling or sealants are common solutions to the problem of exterior moisture, and dehumidifiers can address condensation. A dehumidifier is a household appliance that reduces the level of humidity in a room. ...

Historic concrete shells

The oldest know concrete shell, the Pantheon in Rome, was completed about AD 125, and is still standing. It has a massive concrete dome 43m in diameter. A monolithic structure, it appears to have been sculpted in place by applying thin layers on top of each other in decreasing diameter. Massively thick at the bottom and thinning at the top, the Pantheon is a remarkable feat of engineering. The Pantheon, Rome, in front of which stands the obelisk Macuteo, one of fourteen ancient Egyptian obelisks in Rome. ... Events Construction of the Pantheon (Rome) as it stands today by Hadrian. ... Something that is monolithic is something created in one piece, resembling a monolith such as an obelisk. ...

The Seattle Kingdome was the world's first (and only) concrete-domed multi-purpose stadium. It was completed in 1976 and demolished in 2000. The Kingdome was constructed of triangular segments of reinforced concrete that were cast in place. Thick ribs provide additional support. The Seattle Kingdome, officially known as the King County Domed Stadium, and usually referred to as simply The Kingdome or The Dome, was the worlds first — and only — multi-purpose concrete domed stadium, which was owned and operated by King County, Washington, located at the north end... 1976 (MCMLXXVI) was a leap year starting on Thursday. ... This article is about the year 2000. ... Reinforced concrete at Sainte Jeanne dArc Church (Nice, France): architect Jacques Dror, 1926–1933 Reinforced concrete, also called ferroconcrete in some countries, is concrete in which reinforcement bars (rebars) or fibers have been incorporated to strengthen the material that would otherwise be brittle. ...

Modern concrete shell construction

Modern thin concrete shells, which began to appear in the 1920s, are made from thin steel reinforced concrete, and in many cases lack any ribs or additional reinforcing structures, relying wholly on the shell structure itself. The 1920s was a decade sometimes referred to as the Jazz Age or the Roaring Twenties, usually applied to America. ... The old steel cable of a colliery winding tower Steel is a metal alloy whose major component is iron, with carbon content between 0. ...

Shells may be cast in place, or pre-cast off site and moved into place and assembled. The strongest for of shell is the monolithic shell, which is cast as a single unit. The most common monolithic form is the dome, but ellipsoids and cylinders (resembling concrete Quonset huts) are also possible using similar construction methods. A typical Quonset hut A Quonset hut is a lightweight prefabricated structure of corrugated steel having a semicircular cross section. ...

Geodesic domes may be constructed from concrete sections, or may be constructed of a lightweight foam with a layer of concrete applied over the top. The advantage of this method is that each section of the dome is small and easily handled. The layer of concrete applied to the outside bonds the dome into a semi-monolithic structure. To meet Wikipedias quality standards, this article or section may require cleanup. ...

Monolithic domes are cast in one piece out of reinforced concrete, and date back to the 1960s. Advocates of these domes consider them to be cost-effective and durable structures, especially suitable for areas prone to natural disasters. They also point out the ease of maintenance of these buildings. Monolithic domes can be built as homes, office buildings, or for other purposes. The 1960s decade refers to the years from 1960 to 1969, inclusive. ...

See also

• Thin-shell structure

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. ...

External links

• Mark Ketchum's Concrete Shell page
• Historic Preservation of Thin-Shell Concrete Structures - Includes case studies of the Seattle Kingdome and MIT's Kresge Auditorium, both concrete dome structures.
• Monolithic Dome Institute - Promotes the modern monolithic dome construction technologies as patented by its founder, David South and by Barry South of Dome Technology
• Anonymous instructions for building a thin shell concrete building, casting concrete over a rebar frame