A compound arch is an

arch An arch is a curved vertical structure spanning an open space underneath it. Arches may support the load above them, or they may perform a purely decorative role. As a decorative element, the arch dates back to the 4th millennium BC, but stru ...

built using multiple independent sub-arches stacked vertically, with their arcs of

voussoirs A voussoir (British English, UK: ; American English, US: ) is a wedge-shaped element, typically a stone, which is used in building an arch or vault (architecture), vault.“Voussoir, N., Pronunciation.” Oxford English Dictionary, Oxford Univers ...

placed one on the top of the other. The goal of using a compound arch is usually to increase the overall strength and reliability (if only one order is fractured, the structure still stands). Each of these sub-arches, or "rings", of which the whole compound arch is composed, is called an arch order. In some compound orders their faces are in the same plane. But as a rule the orders are successively recessed, i.e. the innermost sub-arch, or order, is narrow, the next above it broader, the next is broader still, and so on.

History

This system of concentric arches was employed by the Romans early in the

6th century BC The 6th century BC started on the first day of 600 BC and ended on the last day of 501 BC. In Western Asia, the first half of this century was dominated by the Neo-Babylonian Empire, which had risen to power late in the previous century after ...

, in the Cloaca Maxima at Rome; three orders were used where the Cloaca enters the

Tiber The Tiber ( ; ; ) is the List of rivers of Italy, third-longest river in Italy and the longest in Central Italy, rising in the Apennine Mountains in Emilia-Romagna and flowing through Tuscany, Umbria, and Lazio, where it is joined by the R ...

. In the

Anglo-Saxon architecture Anglo-Saxon architecture was a period in the history of architecture in England from the mid-5th century until the Norman Conquest of 1066. Anglo-Saxon secular buildings in Britain were generally simple, constructed mainly using timber with thatc ...

the use dates at least to the late 8th century ( All Saints' Church, Brixworth with two concentric orders made of Roman bricks). The older compound arches were built from semicircular rings, but later the pointed arches were also compounded, for example, to form the west door portal of the Assumption of Blessed Mary and St Nicholas church in Etchingham (14th century). The early French example is the church of Saint-Philbert-de-Grand-Lieu.

Recessed orders

The recessed orders were also known in Ancient Rome ( Arles Amphitheatre, 90 AD, Trier Imperial Baths, 4th century AD). They can be found in

Hagia Sophia Hagia Sophia (; ; ; ; ), officially the Hagia Sophia Grand Mosque (; ), is a mosque and former Church (building), church serving as a major cultural and historical site in Istanbul, Turkey. The last of three church buildings to be successively ...

(537 AD), Basilica of Sant'Apollinare in Classe (also 6th century). Romanesque and Gothic architects clearly preferred the recessed orders; this can be partially explained by the desire to save on expensive

ashlar Ashlar () is a cut and dressed rock (geology), stone, worked using a chisel to achieve a specific form, typically rectangular in shape. The term can also refer to a structure built from such stones. Ashlar is the finest stone masonry unit, a ...

(the core of thick walls and of the widest outer order could then be filled with cheap

rubble Rubble is broken stone, of irregular size, shape and texture; undressed especially as a filling-in. Rubble naturally found in the soil is known also as 'brash' (compare cornbrash)."Rubble" def. 2., "Brash n. 2. def. 1. ''Oxford English Dictionar ...

. File:CloacaMaxima2019.jpg, Outlet of the Cloaca Maxima File:All Saints, Brixworth - Doorway - geograph.org.uk - 5106514.jpg, All Saints' Church, Brixworth File:Church of the Assumption and St Nicholas, High Street, Etchingham (NHLE Code 1276456) (July 2011) (Doorway and Window).jpg, Church of the Assumption and St Nicholas, Etchingham File:Abbatiale Saint-Philbert-de-Grand-Lieu (1).jpg, Church of Saint-Philbert-de-Grand-Lieu

References

Sources

* Arches and vaults {{architecture-stub

History

Recessed orders

See also

References

Sources