Discharging arch

Last updated
Discharging arch of the door of the minaret in the Great Mosque of Kairouan, also called the Mosque of Uqba, in Tunisia. Lintel and discharging arch, minaret of the Great Mosque of Kairouan.jpg
Discharging arch of the door of the minaret in the Great Mosque of Kairouan, also called the Mosque of Uqba, in Tunisia.

A discharging arch or relieving arch is an arch built over a lintel or architrave to take off the superincumbent weight. [1]

Contents

History

The earliest example is found in the Great Pyramid, over the lintels of the entrance passage to the tomb: it consisted of two stones only, resting one against the other. The same object was attained in the Lion Gate and the Treasury of Atreus, both in Mycenae, and in other examples in Greece, where the stones laid in horizontal courses, one projecting over the other, left a triangular hollow space above the lintel of the door, which was subsequently filled in by vertical sculptured stone panels. [1]

The Romans frequently employed the discharging arch, and inside the portico of the Pantheon the architraves have such arches over them. In the Golden Gateway of the palace of Diocletian at Split the discharging arches, semicircular in form, were adopted as architectural features and decorated with mouldings. The same is found in the synagogues in Palestine of the 2nd century; and later, in Byzantine architecture, these moulded archivolts above an architrave constitute one of the characteristics of the style. In the early Christian churches in Rome, where a colonnade divided off the nave and aisles, discharging arches are turned in the frieze just above the architraves. [1]

Notes

Related Research Articles

Post and lintel building system where horizontal elements are held up by vertical elements

In architecture, post and lintel is a building system where strong horizontal elements are held up by strong vertical elements with large spaces between them. This is usually used to hold up a roof, creating a largely open space beneath, for whatever use the building is designed. The horizontal elements are called by a variety of names including lintel, header, architrave or beam, and the supporting vertical elements may be called columns, pillars, or posts. The use of wider elements at the top of the post, called capitals, to help spread the load, is common to many traditions.

Ancient Roman architecture Ancient architecture

Ancient Roman architecture adopted the external language of classical Greek architecture for the purposes of the ancient Romans, but was different from Greek buildings, becoming a new architectural style. The two styles are often considered one body of classical architecture. Roman architecture flourished in the Roman Republic and even more so under the Empire, when the great majority of surviving buildings were constructed. It used new materials, particularly Roman concrete, and newer technologies such as the arch and the dome to make buildings that were typically strong and well-engineered. Large numbers remain in some form across the empire, sometimes complete and still in use to this day.

Pediment Element in classical, neoclassical and baroque architecture

A pediment is an architectural element found particularly in Classical, Neoclassical and Baroque architecture, and its derivatives, consisting of a gable, usually of a triangular shape, placed above the horizontal structure of the lintel, or entablature, if supported by columns. The tympanum, the triangular area within the pediment, is often decorated with relief sculpture. A pediment is sometimes the top element of a portico. For symmetric designs, it provides a centre point and is often used to add grandness to entrances.

Pantheon, Rome Roman temple in Rome

The Pantheon is a former Roman temple, now a Catholic church, in Rome, Italy, on the site of an earlier temple commissioned by Marcus Agrippa during the reign of Augustus. It was rebuilt by the emperor Hadrian and probably dedicated about 126 AD. Its date of construction is uncertain, because Hadrian chose not to inscribe the new temple but rather to retain the inscription of Agrippa's older temple, which had burned down.

Corbel piece of masonry jutting out of a wall to carry any superincumbent weight

In architecture, a corbel is a structural piece of stone, wood or metal jutting from a wall to carry a superincumbent weight, a type of bracket. A corbel is a solid piece of material in the wall, whereas a console is a piece applied to the structure. A piece of timber projecting in the same way was called a "tassel" or a "bragger" in England.

Capital (architecture) part of a column (architecture)

In architecture the capital or chapiter forms the topmost member of a column. It mediates between the column and the load thrusting down upon it, broadening the area of the column's supporting surface. The capital, projecting on each side as it rises to support the abacus, joins the usually square abacus and the usually circular shaft of the column. The capital may be convex, as in the Doric order; concave, as in the inverted bell of the Corinthian order; or scrolling out, as in the Ionic order. These form the three principal types on which all capitals in the classical tradition are based. The Composite order established in the 16th century on a hint from the Arch of Titus, adds Ionic volutes to Corinthian acanthus leaves.

Flying buttress

The flying buttress is a specific form of buttress composed of an arch that extends from the upper portion of a wall to a pier of great mass, in order to convey to the ground the lateral forces that push a wall outwards, which are forces that arise from vaulted ceilings of stone and from wind-loading on roofs.

Entablature architectural element

An entablature is the superstructure of moldings and bands which lies horizontally above columns, resting on their capitals. Entablatures are major elements of classical architecture, and are commonly divided into the architrave, the frieze, and the cornice. The Greek and Roman temples are believed to be based on wooden structures, the design transition from wooden to stone structures being called petrification.

Architrave Lintel beam element in Classical architecture

In classical architecture, an architrave is the lintel or beam that rests on the capitals of columns.

Hypostyle hall with a roof supported by columns

In architecture, a hypostyle hall has a roof which is supported by columns.

Molding (decorative) Class of decorative elements in the ornamentation

Moulding, also known as coving(United Kingdom, Australia), is a strip of material with various profiles used to cover transitions between surfaces or for decoration. It is traditionally made from solid milled wood or plaster, but may be of plastic or reformed wood. In classical architecture and sculpture, the molding is often carved in marble or other stones.

Treasury of Atreus "tholos" tomb located on the Panagitsa Hill at Mycenae, Greece, that dates ca.1250 BC

The Treasury of Atreus or Tomb of Agamemnon is a large tholos or beehive tomb on Panagitsa Hill at Mycenae, Greece, constructed during the Bronze Age around 1250 BC. The stone lintel above the doorway weighs 120 tons, with approximate dimensions 8.3 x 5.2 x 1.2m, the largest in the world. The tomb was used for an unknown period. Mentioned by the Roman geographer Pausanias in the 2nd century AD, it was still visible in 1879 when the German archaeologist Heinrich Schliemann discovered the shaft graves under the "agora" in the Acropolis at Mycenae.

Dentil A small block used as a repeating ornament in the bedmould of a cornice

A dentil is a small block used as a repeating ornament in the bedmould of a cornice. Dentils are found in ancient Greek and Roman architecture, and also in later styles such as Neoclassical, Federal, Georgian Revival, Greek Revival, Renaissance Revival, Second Empire, and Beaux-Arts architecture.

Voussoir building element

A voussoir is a wedge-shaped element, typically a stone, which is used in building an arch or vault.

Gutta A small cone-shaped projection used in the architrave of the Doric order

A gutta is a small water-repelling, cone-shaped projection used near the top of the architrave of the Doric order in classical architecture. At the top of the architrave blocks, a row of six guttae below the narrow projection of the taenia (fillet) formed an element called a regula. A regula was aligned under each triglyph of the Doric frieze. In addition, the underside of the projecting geison above the frieze had rectangular protrusions termed mutules that each had three rows of six guttae. These mutules were aligned above each triglyph and each metope.

This page is a glossary of architecture.

Vault (architecture) architectural term for an arched form used to provide a space with a ceiling or roof

In architecture, a vault is a self-supporting arched form, usually of stone or brick, serving to cover a space with a ceiling or roof. The simplest kind of vault is the barrel vault, which is generally semicircular in shape. The barrel vault is a continuous arch, the length being greater than its diameter. As in building an arch, a temporary support is needed while rings of voussoirs are constructed and the rings placed in position. Until the topmost voussoir, the keystone, is positioned, the vault is not self-supporting. Where timber is easily obtained, this temporary support is provided by centering consisting of a framed truss with a semicircular or segmental head, which supports the voussoirs until the ring of the whole arch is completed. With a barrel vault, the centering can then be shifted on to support the next rings.

Fireplace mantel framework around a fireplace

The fireplace mantel or mantelpiece, also known as a chimneypiece, originated in medieval times as a hood that projected over a fire grate to catch the smoke. The term has evolved to include the decorative framework around the fireplace, and can include elaborate designs extending to the ceiling. Mantelpiece is now the general term for the jambs, mantel shelf, and external accessories of a fireplace. For many centuries, the chimneypiece was the most ornamental and most artistic feature of a room, but as fireplaces have become smaller, and modern methods of heating have been introduced, its artistic as well as its practical significance has lessened.

Gibbs surround

A Gibbs surround or Gibbs Surround is a type of architectural frame surrounding a door, window or niche in the tradition of classical architecture otherwise known as a rusticated doorway or window. The formula is not fixed, but several of the following elements will be found. The door is surrounded by an architrave, or perhaps consists of, or is flanked by, pilasters or columns. These are with "blocking", where rectangular blocks stick out at intervals, usually alternating to represent half the surround. Above the opening there are large rusticated voussoirs and a keystone and a pediment above that. The most essential element is the alternation of blocking with non-blocking elements. Some definitions extend to including arches or square openings merely with alternate blocked elements that continue round the top in the same manner as the sides, as in the rectangular windows of the White House's north front basement level.

Lintel Structural horizontal block that spans the space between two vertical supports

A lintel or lintol is a structural horizontal block that spans the space or opening between two vertical supports. It can be a decorative architectural element, or a combined ornamented structural item. It is often found over portals, doors, windows and fireplaces. In the case of windows, the bottom span is instead referred to as a sill, but, unlike a lintel, does not serve to bear a load to ensure the integrity of the wall. Modern day lintels are made using prestressed concrete and are also referred to as beams in beam and block slabs or ribs in rib and block slabs. These prestressed concrete lintels and blocks are components that are packed together and propped to form a suspended floor concrete slab.

References

Further reading