Building with earth - Gernot MINKE (1)

Openings for doors and windows
Wall apertures will destabilise a wall system.
During earthquakes, diagonal cracks often
occur, starting at the window edges (15.20).
In order to achieve a good bond, lintels
must penetrate at least 40 cm into the wall
(15.21). In this case, however, the area
above the lintel may be weak and may
come off during an earthquake, so the best
solution is to use the lintel as a ring beam
on which the roof structure rests. It is also
recommended that the section below the
window be built as a light, flexible structure,
for instance from wooden panels or wattle
and daub. The following rules have to be
taken into account (15.23 and 15.24).
a) The width of a window should not be
more than 1.2 m and not more than 1 /3 of
the length of the wall.
b) The length of walls between openings
must be at least 1 /3 of their height and not
less than 1 m.
c) Doors must open outward. Opposite the
entrance door should be a large window or
another door, which acts emergency exit
(15.24).
15.20
dangerous
acceptable
15.22
better
best
15.21
15.20 Typical failures
caused by seismic movements
(Tolles et al., 2000)
15.21 Types of lintels
15.22 Stabilised openings
15.23 Recommendable
dimensions of openings
15.24 Recommendable
positions of openings
15.25 to 15.26 Earthquake-resistant
low-cost
housing prototype with
bamboo-reinforced
rammed earth walls,
Guatemala 1978
140
Earthquake-resistant building