A conical vault (Dutch: kegelgewelf) is a vault shaped like (part of) a cone: it runs from a round lower rim tapering up to a point or to a smaller round upper rim. It is used to cover round or semicircular spaces.
How it works
Like other vaults, a conical vault carries its load mainly through compression: the stones or masonry meet in wedge fashion and lead the load along the curved form to the supporting walls. Because of the conical shape the vault is inherently stable and spreads the forces all around:
- Round lower rim — meets a circular or polygonal wall.
- Tapering surfaces — carry the pressure down and out to the rim.
- Point or drum — the form ends in a point or carries a lantern or spire.
Application
- Apses and half-domes — the semicircular end of a church choir can be covered with a cone-shaped vault.
- Round towers and stair towers — a conical vault closes off the top.
- Spires — as a load-bearing base beneath a tower spire.
Points to watch
- A conical vault suits a round or polygonal plan; a rectangular space calls for a cross or barrel vault instead.
- During building a timber centring (form) is needed to support the cone until the vault carries itself.
- It differs from a dome: a dome is spherical, while a conical vault runs straight to a point.
Related terms
- Vault
- Vault rib
- Keystone
- Arch
- Bricklaying
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