AskDefine | Define arch

Dictionary Definition

arch adj
1 (of persons) highest in rank or authority or office; "his arch rival" [syn: arch(a)]
2 (used of behavior or attitude) characteristic of those who treat others with condescension [syn: condescending, patronizing, patronising]
3 expert in skulduggery; "an arch criminal" [syn: arch(a)]

Noun

1 a curved shape in the vertical plane that spans an opening
2 a curved bony structure supporting or enclosing organs (especially arches of the feet)
3 a passageway under an arch [syn: archway]
4 (architecture) a masonry construction (usually curved) for spanning an opening and supporting the weight above it v : form an arch or curve; "her back arches"; "her hips curve nicely" [syn: curve, arc]

User Contributed Dictionary

English

Pronunciation

Noun

  1. An inverted U shape.
  2. An arch-shaped arrangement of trapezoidal stones, designed to redistribute downward force outward.
  3. An architectural element having the shape of an arch

Translations

architectural element

Verb

  1. To form into an arch shape
    The cat arched its back

Translations

Adjective

  1. knowing, clever
    I attempted to hide my emotions, but an arch remark escaped my lips.

Translations

Prefix

arch
  1. Highly placed in a hierarchy, particularly used of church officials
    He eventually rose to the rank of archdeacon
  2. Primary among many
    ''The Joker was Batman's arch-nemesis

Translations

Extensive Definition

An arch is a structure capable of spanning a space while supporting significant weight (e.g. a doorway in a stone wall). True arches appeared as early as the 2nd millennium BC in Mesopotamian brick architecture and in Persian ziggurats (see Chogha Zanbil). True arches were also built by the Babylonians in the 6th century BC (see Ishtar Gate ). The arch then spread to Europe and was adopted by the Ancient Greeks, Etruscans, and Ancient Romans. The arch became an important technique in medieval European cathedral building as well as Islamic architecture. Across the ocean in Mexico and Central America, Mesoamerican civilizations created various types of corbelled arches, such as with the interior tunnels in the Great Pyramid of Cholula and the many styles of corbelled arches built by the Mayan civilization. In Peru, the Inca civilization used a trapezoidal arch in their architecture. The arch is still used today in some modern structures such as bridges.

History

Arches were first created and used by the Mesopotamian, Persian, Harappan, Egyptian, Babylonian, and Assyrian civilizations. Many arches were used in buildings and in monumental architecture, such as in the Ishtar Gate and the ziggurat of Chogha Zanbil. Other arches were used in underground structures such as drains where the problem of lateral thrust is greatly diminished.
From the Middle East, knowledge of arch building spread to Europe. The ancient Romans learned the arch from the Etruscans (who originally migrated out of the Middle East), refined it and employed it for above ground buildings. Throughout the Roman empire, their engineers erected arch structures such as bridges, aqueducts, and gates. They also introduced the triumphal arch as a military monument. Vaults began to be used for roofing large interior spaces such as halls and temples, a function which was also assumed by domed structures from the 1st century BC onwards.
The Roman arch is semicircular, and built from an odd number of arch bricks (called voussoirs). An odd number of bricks is required for there to be a capstone or keystone, the topmost stone in the arch. The Roman arch's shape is the simplest to build, but not the strongest. There is a tendency for the sides to bulge outwards, which must be counteracted by an added weight of masonry to push them inwards. The Romans used this type of semicircular arch freely in many of their secular structures such as aqueducts, palaces and amphitheaters.
The semicircular arch was followed in Europe by the pointed Gothic arch or ogive (derived from the Islamic pointed arch in Moorish Spain), whose centreline more closely followed the forces of compression and which was therefore stronger. The semicircular arch can be flattened to make an elliptical arch as in the Ponte Santa Trinita. The parabolic and catenary arches are now known to be the theoretically strongest forms. Parabolic arches were introduced in construction by the Spanish architect Antoni Gaudí, who admired the structural system of Gothic style, but for the buttresses, which he termed “architectural crutches”. The catenary and parabolic arches carry all horizontal thrust to the foundation and so do not need additional elements.
The horseshoe arch is based on the semicircular arch, but its lower ends are extended further round the circle until they start to converge. The first examples known are carved into rock in India in the first century AD, while the first known built horseshoe arches are known from Aksum (modern day Ethiopia and Eritrea) from around the 3rd–4th century, around the same time as the earliest contemporary examples in Syria, suggesting either an Aksumite or Syrian origin for the type of arch. It was used in Spanish Visigothic architecture, Islamic architecture and mudéjar architecture, as in the Great Mosque of Damascus and in later Moorish buildings. It was used for decoration rather than for strength.
In Mexico and Central America, Mesoamerican civilizations created various types of corbelled arches, such as with the interior tunnels in the Great Pyramid of Cholula and the many styles of corbelled arches built by the Mayan civilization.

Construction

An arch requires all of its elements to hold it together, raising the question of how an arch is constructed. One answer is to build a frame (historically, of wood) which exactly follows the form of the underside of the arch. This is known as a centre or centring. The voussoirs are laid on it until the arch is complete and self-supporting. For an arch higher than head height, scaffolding would in any case be required by the builders, so the scaffolding can be combined with the arch support. Occasionally arches would fall down when the frame was removed if construction or planning had been incorrect. (The A85 bridge at Dalmally, Scotland suffered this fate on its first attempt, in the 1940s). The interior and lower line or curve of an arch is known as the intrados.
Old arches sometimes need reinforcement due to decay of the keystones, known as bald arch.
The gallery shows arch forms displayed in roughly the order in which they were developed.

Technical aspects

The arch is significant because, in theory at least, it provides a structure which eliminates tensile stresses in spanning an open space. All the forces are resolved into compressive stresses. This is useful because several of the available building materials such as stone, cast iron and concrete can strongly resist compression but are very weak when tension, shear or torsional stress is applied to them. By using the arch configuration, significant spans can be achieved. This is because all the compressive forces hold it together in a state of equilibrium. This even applies to frictionless surfaces. However, one downside is that an arch pushes outward at the base, and this needs to be restrained in some way, either with heavy sides and friction or angled cuts into bedrock or similar.
This same principle holds when the force acting on the arch is not vertical such as in spanning a doorway, but horizontal, such as in arched retaining walls or dams.
Even when using concrete, where the structure may be monolithic, the principle of the arch is used so as to benefit from the concrete's strength in resisting compressive stress. Where any other form of stress is raised, it has to be resisted by carefully placed reinforcement rods or fibres. (See Arch bridge.)

Other types

References

  • Understanding Architecture: Its Elements History and Meaning pp. 27-8

External links

arch in Afrikaans: Boog (boukunde)
arch in Min Nan: Oân-kong
arch in Belarusian (Tarashkevitsa): Арка
arch in Bulgarian: Арка
arch in Catalan: Arc (arquitectura)
arch in German: Bogen (Architektur)
arch in Spanish: Arco (construcción)
arch in Esperanto: Arko (arkitekturo)
arch in Basque: Arku (arkitektura)
arch in French: Arc (architecture)
arch in Galician: Arco (arquitectura)
arch in Korean: 아치
arch in Hindi: चाप
arch in Croatian: Luk (arhitektura)
arch in Icelandic: Bogi (byggingarlist)
arch in Italian: Arco (architettura)
arch in Hebrew: קשת (מבנה)
arch in Latin: Arcus (architectura)
arch in Latvian: Arka
arch in Hungarian: Boltív
arch in Dutch: Boog (bouwkunde)
arch in Japanese: アーチ
arch in Norwegian: Bue (arkitektur)
arch in Norwegian Nynorsk: Boge i arkitekturen
arch in Narom: Arche
arch in Polish: Łuk (architektura)
arch in Portuguese: Arco (arquitectura)
arch in Russian: Арка
arch in Simple English: Arch
arch in Finnish: Kaari (rakennustekniikka)
arch in Swedish: Båge
arch in Thai: อาร์ช
arch in Ukrainian: Арка
arch in Chinese: 拱

Synonyms, Antonyms and Related Words

Machiavellian, Machiavellic, acute, apse, arc, arcade, arcature, arch over, arched roof, archway, artful, astute, banner, bantam, barrow, basket-handle arch, bend, bend back, bestraddle, bestride, bold, boundary stone, bow, brass, bridge, bust, cagey, cairn, camber, canny, capital, cardinal, ceilinged roof, cenotaph, central, champion, cheeky, chief, clever, clubfoot, cocky, column, concameration, concha, conspicuous, consummate, coquettish, cove, coy, crafty, cromlech, crook, cross, crowning, cunning, cup, cupola, curl, curvation, curvature, curve, cute, cyclolith, deceitful, decurve, deep, deep-laid, deflect, derisive, designing, devilish, digit, diplomatic, dog, dolmen, dome, dominant, elfish, elvish, embow, extend over, extraordinary, extreme, extremity, feline, fetlock, first, flex, flippant, focal, foolish, foot, footstone, forefoot, foremost, forepaw, foxy, fresh, full of mischief, geodesic dome, grave, gravestone, great, greatest, guileful, hang over, harefoot, head, headmost, headstone, heel, hegemonic, high-spirited, hoarstone, hoof, hook, hump, hunch, igloo, imbricate, impish, incurvate, incurve, inflect, ingenious, inscription, insidious, instep, inventive, jut, keystone, knavish, knowing, lap, lap over, leading, lie over, loop, magisterial, main, major, malapert, marker, master, mausoleum, megalith, memento, memorial, memorial arch, memorial column, memorial statue, memorial stone, menhir, mischief-loving, mischievous, mocking, monolith, monument, mound, necrology, notable, noteworthy, obelisk, obituary, ogive, overarch, overhang, overlap, overlie, override, overruling, pad, paramount, pastern, patte, paw, pawky, pedal extremity, pedes, pert, pes, pied, pillar, plaque, playful, politic, prankish, pranksome, pranky, predominant, preeminent, premier, preponderant, prevailing, primal, primary, prime, principal, prize, puckish, pug, pyramid, ranking, ready, recurve, reflect, reflex, reliquary, remembrance, resourceful, retroflex, ribbon, roguish, rostral column, round, ruling, sag, saucy, scampish, scapegrace, scheming, serpentine, shaft, sharp, shifty, shingle, shrewd, shrine, skewback, slick, slippery, sly, smooth, snaky, sneaky, sole, sophistical, sovereign, span, splayfoot, sportive, star, stealthy, stela, stellar, stone, strategic, stupa, subtile, subtle, supereminent, supple, swag, sweep, tablet, tactical, testimonial, toe, tomb, tombstone, tootsy, tope, topflight, trefoil arch, trickish, tricksy, tricky, trophy, trotter, turn, twitting, ungula, vault, vaulting, voussoir, vulpine, waggish, wary, wily, wind
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