A dome is a special type of shell roof of semi-spherical or semi-elliptical shape. The modern thin shell dome may be considered as an evolution of a structural form known and used by man from ancient ages.
Dome structures may be divided into two main divisions:
- Smooth shell domes
- Ribbed domes
Smooth shell domes may be divided into:
- Domes with shells of uniform thickness.
- Domes with shells of uniformly varying thickness.
Smooth shell domes are constructed by brick, stone, concrete or tile. Ribbed domes may be built in steel, concrete or wood. A dome may be constructed with or without a lantern.
The structure of the dome is such that within certain height and diameter ratios very small thickness is required. They are used where architectural treatment is required such as in monumental structures or where roofs have to be constructed on buildings circular in plan or hexagonal in plan.