Earthquake protection for poor people’s houses
Practical Action
Reinforcement for ring beams may take many shapes:
Concrete columns and beams are the most expensive solution.
Timber beams, on top of and within the walls are usually much cheaper. The Turkish
building code suggests the use of horizontal timber bond-beams at four levels: at the
basement, under and above windows, and under the roof. These bond-beams can be
double, with a 10 x 10cm timber profile at
each side of the wall, connected by 5 x 10cm
ties at 50cm intervals (Figure 3). They can
also be single, on the outer face of the wall,
and braced in the corners (Figure 4).
Timber frames were also suggested after the
1976 earthquake in Guatemala, where the
traditional adobe wall is much thinner,
provides little structural support, and acts as
more of an infill than elsewhere. The frame
should consist of horizontal beams at roof and
basement levels with vertical posts at corners Figure 5
and intersections, and braces to make the
frame more rigid (Figure 5). Such wooden
frames require good connections with the
adobe masonry, through anchor bolts, nails or
wire mesh.
In Mexico, U-shaped or hollow adobes have
been suggested, to incorporate timber or
concrete reinforcement more easily (Figure 6).
Steel bars can be used, in horizontal or
vertical joints, to tie walls together or to the
foundation, but they are expensive. In Ecuador
and Honduras barbed wire or other steel wire
has therefore been suggested for use in
Figure 6
combination with a timber frame (Figure 7).
Welded mesh in the joints is an alternative
commonly used in the south west of the USA
and in southern Africa (Figure 8). Wire mesh
incorporated into a plaster becomes
ferrocement, and can be used to reinforce
high-stress areas, around corners or openings
(Figure 9).
The Turkish code allows the wooden bond-
beams to be replaced by canes 5cm apart,
tied every 50cm. In Peru, both vertical and
Figure 7
horizontal reinforcements with reeds and
bamboo are used. One method uses bitumen-
stabilized adobes (bitumen is mixed in with the soil), with small holes in the vertical
joints for a halved bamboo (also painted with bitumen) to pass through. Horizontal
reinforcement then consists of quartered bamboo laths (Figure 10).
In India, split bamboo mesh, dipped in bitumen, is used as a reinforcement of the
plaster on adobe walls.
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