Building with Earth: Design and Technology of a Sustainable Architecture

Structurally optimised domes

In order to avoid the disadvantages of

Nubian dome technology, a new technique

for making domes using a rotational guide

was developed at the BRL. With this tech-

nique, the structurally optimal geometry of

the dome can be achieved without form-

work. This geometry avoids all tensile ring

forces as well as compressive ring forces.

The derivation of this shape is described on

p. 116 of this chapter.

The rotational guide has a right-angled

head into which the blocks are placed. This

angle can be moved on a curved metal

T-section bent to shape. This T-section is

fixed to a rotating arm, which is in turn fixed

to a vertical post. Illustrations 14.65to 14.68

show the application of this technique to

a dome with a 7 m free span and 6 m of

clear height, which was built at the Univer-

sity of Kassel in Germany in 1992. The apex

is covered with a 16-sided pyramidal sky-

light. The thickness of the dome wall is only

20 cm and the cross-section was derived

using a computer program in order to get

the optimum shape with no ring forces, as

described on p. 116 of this chapter. In order

to prevent the blocks of the upper layers

from sliding while under construction, the

courses are not exactly perpendicular

to the surface of the dome, but are slightly

127 Designs of building elements

14.63

14.64

14.66 14.65

14.67 14.68

14.62