Dome

This article is about the building structural element. For the Japanese racing car constructor, see Dome (constructor)

File:StPetersDome.jpg

St Peter's Basilica (topped with a lantern), Rome

A dome is a common structural element of architecture that resembles the hollow upper half of a sphere. Domes do not have to be perfectly spherical in cross-section, however; a dome may be a section through an ellipse. If the baseline is taken parallel to the shorter of an ellipse's two diameters, a tall dome results, giving a sense of upward reach. A section across the longer axis results in a low dome, capping the volume instead. A very low dome is a saucer dome (see below). All the surfaces of any dome are curved. A spectacular innovation, one that is at the heart of Baroque style, is the oval dome, which gives axial direction and movement to the space beneath it. Though the oval dome is identified with churches of Bernini and Borromini, the first oval dome was erected by Vignola for a small chapel, Sant'Andrea in via Flaminia often called Sant'Andrea del Vignola, which was commissioned in 1552 by Julius III, and finished the following year [1], the biggest oval dome was built in the basilica of Vicoforte by Francesco Gallo.

Three domes that have been disproportionately influential in later architecture are those of Hagia Sophia in Constantinople, the Dome of the Rock in Jerusalem and the Pantheon in Rome. In Western architecture, the most influential domes built since the Renaissance have been those of St. Peter's Basilica in Rome and Jules Hardouin-Mansart's dome at Les Invalides in Paris. The dome of St. Paul's Cathedral in London was the inspiration for the United States Capitol in Washington, which in turn inspired domes of most of the US state capitols. See further influential domes below.

A cathedral is often referred to as a duomo in Italian or "dom" in German, not because so many are crowned with crossing domes over the space where transepts intersect the nave, but from the latin "domus", house, in this case the "domus dei", the house of God.. A dome is a mark of palatial ambitions whenever it is seen crowning a residence. The first residential domes were seen in Nero's Domus Aurea that covered the slope of the Palatine Hill, built after the Great Fire of Rome of AD 64 with a lavishness that scandalized the senatorial class.

In the 20th century, thin "eggshell" domes of pre-stressed concrete by architect-engineers such as Nervi opened new directions in fluid vaulted spaces enclosed beaneath freeform domed space which now might be supported merely at points rather than in the traditional constricting ring.

Characteristics

A dome can be considered as an arch which has been rotated around its vertical axis. As such, domes have a great deal of structural strength. A small dome can be constructed of ordinary masonry, held together by friction and compressive forces. Larger domes built after Brunelleschi's dome that triumphantly spanned the crossing of Santa Maria del Fiore, the duomo of Florence, have all been built as double domes, with inner and outer shells.

Interior of the dome, San Francisco City Hall

The concave triangular or trapezoidal sections of vaulting that provide the transition between a dome and the square base on which it is set and transfer the weight of the dome are called pendentives. (A less sophisticated version of a pendentive is a squinch.) Under the dome illustrated at left, the pendentives bear circular medallions in bas relief.

A half-dome forms the head of an exedra or its smaller version, a niche. In Late Antiquity, the exedra developed into the apse, with separate developments in Romanesque and Byzantine practice.

Many domes are topped by a lantern, a structure with openings (or windows) to admit light in the cupola.

Many sports stadiums are domed, especially in climates that have widely-variable summer and winter weather. The first such stadium was the Astrodome in Houston, Texas. A major improvement to the domed stadium was accomplished with the construction of SkyDome in Toronto, Ontario, the first domed stadium with a retractable roof.

Gandon's Four Courts, Dublin, with a saucer dome.

Saucer dome

A saucer dome is the architectural term used for a low pitched shallow dome. Described geometrically as being of circular base and a segmental (less than a semicircle) section.

Gaining in popularity from the 18th century onwards, the saucer dome is often a feature of interior design, viewed from below it resembles the shallow concave shape of a saucer. The dome itself being often contained in the space between ceiling and attic is invisible externally. These domes are usually decorated internally by ornate plaster-work, occasionally they are frescoed.

They are seen occasionally externally in Byzantine churches and mosques.

St. Basil's Cathedral, with onion domes.

File:Mosque dome 2.jpg

The dome of a mosque in Dubai.

Onion dome

Main article: onion dome.

The onion dome resembles more than half of a sphere, exemplified by Saint Basil's Cathedral in Moscow and the Taj Mahal. They are found mostly in eastern architecture, particularly in Russia, Turkey, the Middle East, and even India.

Famous domes

Listed in order of their completion:

• 27 BC - The Pantheon, Rome, Italy.
• 537 - Hagia Sophia, Constantinople
• 691 - Dome of the Rock, Jerusalem.
• 1312 - Dome of Soltaniyeh, Iran.
• 1436 - The Duomo, Florence, Italy.
• 1502 - The Tempietto, Rome, Italy.
• 1557 - Suleiman Mosque, Istanbul, Turkey.
• 1574 - Selimiye Mosque, Edirne, Turkey.
• 1593 - St. Peter's Basilica, Rome, Italy.
• 1616 - The Blue Mosque, Istanbul, Turkey.
• 1653 - The Taj Mahal, Agra, India.
• 1659 - Gol Gumbaz, Bijapur Karnataka India
• 1708 - Les Invalides, Paris, France.
• 1708 - St Paul's Cathedral, London, England.
• 1733 - Basilica Regina Montis Regalis, Vicoforte, Italy.
• 1749 - The Radcliffe Camera, Oxford, England.
• 1858 - St Isaac's Cathedral, St Petersburg, Russia.
• 1850s - The United States Capitol, Washington, DC, USA.
• 1965 - The Astrodome, Houston, TX, USA.
• 1989 - SkyDome aka Roger's Centre , Toronto, ON, Canada
• 2000 - The Millennium Dome, London, England. (This is not a true dome as it is not self supporting.)

Xanadu House

The Xanadu House was a home that used the concept of domes heavily in its shape and design. The home was one of the first non-indigenous homes to use curved surfaces throughout the exterior and interior.

See also

• Geodesic dome
• Cupola
• Concrete dome
• Doming technique
• Rotunda
• Dome (geology)
• Dome (mathematics)
• Dome (Slang)
• Gonbad

External links

• The Dome of Brunelleschi, Florence virtual reality movie and pictures