- Voussoir
A voussoir is a wedge-shaped element, typically a stone, used in building an
arch . [cite web
url=http://www.pitt.edu/~medart/menuglossary/listuv.htm#letterV
title=Glossary of Medieval Art and Architecture - Voussoir
publisher=University of Pittsburgh
accessdate=2007-06-24]Although each unit of stone in an arch or vault is known as a voussoir, there are two specified voussoir components of an arch: the keystone and the springer. The keystone is the center stone or masonry unit at the apex of an arch, often decorated, embellished or exaggerated in size. No true arching action occurs until this unit is in place. The springer is the lowermost voussoir, located where the curve of the arch springs from the vertical support or abuttment of the wall or pier.
The word is a mason's term borrowed in
Middle English from French verbs connoting a "turn" ("OED "). Each wedge-shaped voussoir "turns aside" the thrust of the mass above, transferring it from stone to stone to the final edge, which is horizontal and passes the thrust to the supports. Voussoir arches distribute weight efficiently and take maximum advantage of thecompressive strength of stone, as in anarch bridge . The outer boundaries of a voussoir are the extrados.In Moorish or Islamic architecture, the voussoirs are often in alternating colors, usually red and white.
Notes
References
* [http://www.ontarioarchitecture.com/voussoir.htm Photo repertory of voussoirs]
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