What is a Florentine arch?
A Florentine arch is a round or segmental arch whose outer curve (extrados) and inner curve (intrados) are not concentric: the intrados has a larger radius than the extrados, so the arch is thick at the springing and tapers towards the crown. The arch takes its name from the Renaissance architecture of Florence, where this form was widely used in arcades and windows.
Geometry
In an ordinary semicircular arch, the intrados and extrados share a common centre, so the arch has the same depth throughout. In the Florentine arch the centres of the two curves do not coincide. As a result:
- The springing zone (where the arch begins) is relatively deep and thick.
- Towards the keystone the arch becomes narrower.
- The intrados can form a flatter, wider opening than a strictly semicircular arch.
Application
The Florentine arch became popular in the Italian Renaissance, particularly in Florentine palaces (palazzi) and cloister courtyards. It is applied in:
- Arcades and colonnades, where a slender, elegant arch form is desired;
- Windows and door openings in natural stone or masonry;
- Loggias, where the slimmer crown enhances openness.
Properties
The differing geometry produces a visually lighter arch but requires carefully cut arch stones (voussoirs), because each stone has its own individual wedge shape.
Related terms
- Round arch
- Segmental arch
- Keystone
- Arch construction
- Voussoir
- Springing
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