Building with Earth: Design and Technology of a Sustainable Architecture

Domes

The Nubian dome technique has been
known in Upper Egypt for thousands of
years. In this technique, circumferential
courses of adobes are laid using a movable
guide (14.62).
With this technique, blocks are turned on
edge. This avoids slippage of the freshly laid
blocks. However, this requires that special
wedge-shaped blocks be used periodically
(14.63). Due to the high labour input
required most domes were built without
turning the blocks, that is, placing them in
radially.
The main disadvantage of the Nubian
domes technique is that only spherical
domes can be produced. As explained in
this chapter, p. 116, in spherical domes, ten-
sile ring forces occur in the bottom
portions. Therefore, when covering larger

spans, steel strips or reinforced concrete ring

beams or other strengthening elements

have to be additionally applied. If this is not

considered, domes might fail, as has hap-

pened in practice.

The group Development Workshop,

Lauserte, France, built several residences,

offices and public buildings in Niger using a

modified version of this technique, shown in

14.64. Here, instead of the centrally mount-

ed rotating guide, an eccentric rotating

guide is used. By this, the shape generated

can be such that the tensile ring forces in

the lower part are avoided. However, com-

pressive ring forces thus created might

cause problems if larger openings are made

for entrances or windows.

126 Designs of building elements

14.59 to 14.60 Models

of different dome shapes

deriving from the Nubian

and Afghan techniques

(BRL)

14.61 Persian dome

with wind catchers

14.62 to 14.63 Nubian

dome (CRATerre, 1979)

14.64 Modification

of Nubian dome with

eccentric guide

14.65 to 14.68 Proto-

type dome (BRL)

14. 61

14.59

14.60