Part III

Short-bored piled foundations are used 1)_____ small houses and lightweight framed buildings constructed 2) _____ soils that expand and contract 3) _____ changes in the moisture content. These soil types include clay and black cotton.

The type of foundation shown in Figure 8.8 can be constructed quite quickly and avoid the need to dig deep trenches. Short-bored piles are more effective and cheaper than conventional foundations if the soil responds easily to the changes 4) _____ the atmosphere.

Figure 8.8 Short-bored Pile Foundation

These foundations are not suitable 5) _____ use on rock, flint or sites with many tree roots because the holes must be straight and consistent in diameter.

The holes are dug 6) _____ hands with an auger and then concrete is poured 7) _____ them to form a column in the ground when it hardens. The concrete columns in the holes in the ground are the piles.

The measurements in Table 8.1 are typical dimensions for short-bored piles.

Table 8.1 Measurements for Short-bored Piles

Components	Measurements (mm)
Depth of the hole for the piles	2500-3000
Pile diameter	250-360
Pile spacing
Beam width for 225 mm wall
Beam depth for 225 mm wall	150-200
Reinforcement diameter	15 mm with 6 mm stirrups

Figure 8.9 Timber Displacement Piles

Figure 8.9 represents timber displacement piles for lightweight buildings. For this foundation straight tree trunks should be used and treated with preservative and sharpened 8) _____ the ends to drive them 9) _____ the ground. It is better to use an auger to remove some 10) _____ the pile-driving process is started.

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