Building with earth - Gernot MINKE (1)

14.63
14.62
14.64
14.66 14.65
14.67 14.68
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 technique,
the structurally optimal geometry of
the dome can be achieved without formwork.
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 14.65 to 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 University
of Kassel in Germany in 1992. The apex
is covered with a 16-sided pyramidal skylight.
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
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Designs of building elements