Pendentive

The pendentives are shown in yellow.

A pendentive is a constructive device permitting the placing of a circular dome over a square room or an elliptical dome over a rectangular room. The pendentives, which are triangular segments of a sphere, taper to points at the bottom and spread at the top to establish the continuous circular or elliptical base needed for the dome. In masonry the pendentives thus receive the weight of the dome, concentrating it at the four corners where it can be received by the piers beneath.

Prior to the pendentive's development, the device of corbelling or the use of the squinch in the corners of a room had been employed. Pendentives were commonly used in Orthodox, Renaissance, and Baroque churches, with a drum with windows often inserted between the pendentives and the dome. The first experimentation with pendentives were made in Roman dome construction beginning in the 2nd–3rd century AD, while full development of the form was achieved in the 6th century Eastern Roman Hagia Sophia at Constantinople. The diameter of its central dome remained unsurpassed anywhere in the world until the Renaissance Florence Cathedral, itself not a pendentive dome.

Gallery

• 
  Arches (left and right), dome (top) and pendentive (centre) in Moscow Cathedral
• 
  Holy Trinity Church in the Czech Republic
• 
  Formation of a pendentive
• 
  A pendentive, labelled A
• 
  Pendentive structure

See also

• Hagia Sophia
• Squinch

Sources

• Heinle, Erwin; Schlaich, Jörg (1996), Kuppeln aller Zeiten, aller Kulturen, Stuttgart, ISBN 3-421-03062-6{{citation}}: CS1 maint: location missing publisher (link)
• Rasch, Jürgen (1985), "Die Kuppel in der römischen Architektur. Entwicklung, Formgebung, Konstruktion", Architectura, vol. 15, pp. 117–139