W. Papworth (1852);
J. Parker (1850);
Sturgis et al. (1901–2)
arch, the spanning of a wall opening by means of separate units (such as bricks or stone blocks) assembled into an upward curve that maintains its shape and stability through the mutual pressure of a load and the separate pieces. The weight of the supported load is thus converted into downward and outward lateral pressures called thrusts, which are received by the solid piers (abutments) flanking the opening. The blocks, called voussoirs, composing the arch usually have a wedge shape but they can be rectangular with wedge-shaped joints between them. The underside of the arch is the intrados or soffit and the upper surface above the crown block (keystone) of the arch is the extrados. The point where the arch starts to curve is the foot of the arch, and the stones there are the springers. The surface above the haunch (just below the beginning of the curve) contained within a line drawn perpendicular to the springing line (from which the arch curves), and another drawn horizontal to the crown is the spandril. In modern fireproof construction the word arch is also used for the masonry that fills the space between steel beams and acts as a floor support. The arch was used by the Egyptians, Babylonians, and Greeks, chiefly for underground drains, and also by the Assyrians in the construction of vaulted and domed chambers. In Europe the oldest known arch is the Cloaca Maxima, the huge drain at Rome built by Lucius Tarquinius Priscus c.578 BC The Romans developed the semicircular arch, modeled on earlier Etruscan structures, in the vaults and domes of their monumental buildings. Its use was continued in early Christian, Byzantine, and Romanesque architecture. In the 13th cent. the pointed arch (used as early as 722 BC in Assyrian drains) came into general use. The contact of Europeans with Saracenic architecture during the Crusades is offered among other theories for its introduction into Europe. But it is likely that the pointed arch may have been independently rediscovered in Europe in the Middle Ages as a device for solving many of the mechanical difficulties of vault construction. Its adoption was an essential element in the evolution of the Gothic system of design. With the Renaissance there was a return to the round arch, which prevailed until the 19th-century invention of steel beams for wide spans relegated the arch to a purely decorative function. Although the circular and pointed forms have predominated in the West, the Muslim nations of the East developed a variety of other arched shapes, including the ogee arch used in Persia and India, the horseshoe arch used in Spain and North Africa, and the multifoil or scalloped arch used especially in the Muslim architecture of Spain. In the 20th cent. arches often take a parabolic shape. They are usually constructed with laminated wood or reinforced concrete, materials that give greater lightness and strength to the structure. See triumphal arch.
arch1 / ärch/ • n. a curved symmetrical structure spanning an opening and typically supporting the weight of a bridge, roof, or wall above it. ∎ a structure of this type forming a passageway or a ceremonial monument: a triumphal arch. ∎ a shape resembling such a structure or a thing with such a shape: the delicate arch of his eyebrows. ∎ the inner side of the foot. • v. 1. [intr.] have the curved shape of an arch: a bridge that arched over a canal. ∎ form or cause to form the curved shape of an arch: [intr.] her eyebrows arched in surprise | [tr.] she arched her back. 2. [tr.] provide (a bridge, building, or part of a building) with an arch. ∎ archaic or poetic/lit. span (something) by or as if by an arch. arch2 • adj. deliberately or affectedly playful and teasing: arch observations about even the most mundane matters. DERIVATIVES: arch·ly adv. arch·ness n.
kabyle tribal structure.
The arch is a tribal structure founded on real or sometimes imagined family relationships that emerged in the Kabylic region of North Africa during the fifteenth century, when the dynastic system that had provided considerable central government control disintegrated. Free of external authority, different tribes needed to provide themselves with tools for dealing with conflict, land allocation, and other critical problems. In this context they developed relationships, and alliances merged within larger structures known as arch (plural, arouch ). Under the Ottomans this sociopolitical form of organization was maintained largely intact for four centuries, but it faded away progressively during the colonial period as more and more power was assumed by the state.
In spring 2001 two events in the Kabylia, the killing by police of a high school student on 18 April and subsequent student demonstrations commemorating the 1980 Berber Spring, led to widespread demonstrations and violent repression by securty forces that resulted in the deaths of more than fifty-one and injury to some 1,500. The period and its events came to be known as Black Spring. One local response was the creation of a populist movement known as the Coordination des Archs, which resurrected the traditional institution as a vehicle for expressing the social, cultural, and political demands of the Kabyles within an Algerian system dominated by Arabs. A laterally structured organization that reached decisions by consensus, it represented Kabyles from a broad range of communities and classes in seven wilayas (provinces)—Tizi Ouzou, Boujaia, Bouira, Setif, Bordj, Bou Arreridj, Boumerdes, and Algiers. In its platform, elaborated in the meeting of Illoula Oumalou on 17 May 2001, this essentially pacifistic organization affirmed its autonomy from state institutions and political parties. Its tactics included boycotts of national events and holidays, sit-ins, demonstrations, and celebrations of local culture. Because of its inclusive and populist approach, the Coordination encountered a considerable amount of internal dissidence and was criticized by Berber political parties. It did, however, achieve significant success as an inter-locuter with the Algerian government.
see also berber spring; black spring.
Brett, Michael, and Fentress, Elizabeth. The Berbers. Oxford, U.K.: Blackwell, 1997.
Azzedine G. Mansour
Hence arch vb. XIV.