Onion domeAn onion dome is a dome whose shape resembles an onion. Such domes are often larger in diameter than the tholobate (drum) upon which they sit, and their height usually exceeds their width. They taper smoothly upwards to a point. It is a typical feature of churches belonging to the Russian Orthodox church. There are similar buildings in other Eastern European countries, and occasionally in Western Europe: Bavaria (Germany), Austria, and northeastern Italy.
Architecture of RussiaThe architecture of Russia refers to the architecture of modern Russia as well as the architecture of both the original Kievan Rus', the Russian principalities, and Imperial Russia. Due to the geographical size of modern and Imperial Russia, it typically refers to architecture built in European Russia, as well as European influenced architecture in the conquered territories of the Empire. The vernacular architecture stems from wooden construction traditions, and monumental masonry construction started to appear during the Kievan Rus’ era in what is now modern Ukraine.
TholobateA tholobate (from tholobates) or drum is the upright part of a building on which a dome is raised. It is generally in the shape of a cylinder or a polygonal prism. The name derives from the tholos, the Greek term for a round building with a roof and a circular wall. In the earlier Byzantine church architecture the dome rested directly on the pendentives and the windows were pierced in the dome itself; in later examples, between the pendentive and the dome an intervening circular wall was built in which the windows were pierced.
Semi-domeIn architecture, a semi-dome (or half-dome) is a half dome that covers a semi-circular area in a building. Semi-domes are a common feature of apses in Ancient Roman and traditional church architecture, and in mosques and iwans in Islamic architecture. A semi-dome, or the whole apse, may also be called a conch after the scallop shell often carved as decoration of the semi-dome (all shells were conches in Ancient Greek), though this is usually used for subsidiary semi-domes, rather than the one over the main apse.
CofferA coffer (or coffering) in architecture is a series of sunken panels in the shape of a square, rectangle, or octagon in a ceiling, soffit or vault. A series of these sunken panels was often used as decoration for a ceiling or a vault, also called caissons ("boxes"), or lacunaria ("spaces, openings"), so that a coffered ceiling can be called a lacunar ceiling: the strength of the structure is in the framework of the coffers.
Catenary archA catenary arch is a type of architectural arch that follows an inverted catenary curve. The catenary curve has been employed in buildings since ancient times. It forms an underlying principle to the overall system of vaults and buttresses in stone vaulted Gothic cathedrals and in Renaissance domes. It is not a parabolic arch. The 17th-century scientist Robert Hooke wrote: "Ut pendet continuum flexile, sic stabit contiguum rigidum inversum", or, "As hangs a flexible cable so, inverted, stand the touching pieces of an arch.
Shell (structure)A shell is a three-dimensional solid structural element whose thickness is very small compared to its other dimensions. It is characterized in structural terms by mid-plane stress which is both coplanar and normal to the surface. A shell can be derived from a plate in two steps: by initially forming the middle surface as a singly or doubly curved surface, then by applying loads which are coplanar to the plate's plane thus generating significant stresses. Materials range from concrete (a concrete shell) to fabric (as in fabric structures).
ExedraAn exedra (plural: exedras or exedrae) is a semicircular architectural recess or platform, sometimes crowned by a semi-dome, and either set into a building's façade or free-standing. The original Greek sense (ἐξέδρα, a seat out of doors) was applied to a room that opened onto a stoa, ringed with curved high-backed stone benches, a suitable place for conversation. An exedra may also be expressed by a curved break in a colonnade, perhaps with a semicircular seat. The exedra would typically have an apsidal podium that supported the stone bench.
Oculus (architecture)An oculus (; : oculi) is a circular opening in the center of a dome or in a wall. Originating in antiquity, it is a feature of Byzantine and Neoclassical architecture. It is also known as an œil-de-boeuf from the French, or simply a "bull's-eye". The oculus was used by the Ancient Romans, one of the finest examples being that in the dome of the Pantheon. Open to the weather, it allows rain and air to enter and fall to the floor, where it is carried away through drains.
Parabolic archA parabolic arch is an arch in the shape of a parabola. In structures, their curve represents an efficient method of load, and so can be found in bridges and in architecture in a variety of forms. While a parabolic arch may resemble a catenary arch, a parabola is a quadratic function while a catenary is the hyperbolic cosine, cosh(x), a sum of two exponential functions. One parabola is f(x) = x2 + 3x − 1, and hyperbolic cosine is cosh(x) = ex + e−x/2. The curves are unrelated.
