A melon vault is a domed vault divided by ribs or folds into a number of equal, curved segments (webs), so that seen from below it resembles a sliced melon. It is also called an umbrella dome, pumpkin dome or parachute dome; the German term is Melonengewölbe or Schirmgewölbe.
How it is built up
An ordinary dome is one continuous spherical surface. In a melon vault the vault rises in segments between ribs:
- Each segment is curved in plan (convex or concave) rather than straight
- The segments meet at a single point at the crown, or around an oculus (a round opening)
- The ribs act as load-bearing ribs: the forces are led to a limited number of springing points rather than spread evenly around the whole circumference
Because the load travels through the ribs to a few supports, the area between the springings can stay open — for windows or niches, for example.
Where you find it
The melon vault belongs mainly to prestigious architecture:
- Roman architecture — the Serapeum at Hadrian’s Villa near Tivoli holds one of the best-known early examples
- Renaissance and Baroque — domes over chapels, stair halls and grand rooms
- Byzantine and Islamic architecture — related ribbed dome forms
When restoring a melon vault, the ribs deserve the most attention: cracks running along a rib point to settlement at the springing or to the supporting walls spreading outwards. A structural assessment is needed before any repointing or repair.
Related terms
- Vault
- Dome
- Vault rib
- Cloister vault
- Rib vault
- Oculus
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