Building Services / Trades > Piling and Foundations Cape Town

What is piling ?

Deep foundations are sometimes indicated by geotechnical engineers when soil conditions are poor or a heavy design load needs to be carried.

Piling makes deep foundations possible. Piles are commonly made from reinforced concrete and steel

Common types of piling

Auger Piles

Auger piling is a commonly used piling technique since it is best suited to partially saturated soils. An auger rig drills the piles into place.

Drilling is carried out by rotation of the drilling head and lowering of the auger allowing it to penetrate into the soil. Once the auger flight is full with soil it is withdrawn and spun off. This procedure is repeated until the desired depth is reached.

Once the drilled hole has been completed, a reinforcing cage is lowered down into position. The shaft is then filled with concrete and is vibrated  to assist compaction of the liquid concrete.

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Continuous Flight Auger (CFA)

CFA is suited to saturated ground conditions where collapse and groundwater are a problem. These piles are installed by means of a hollow continuous flight auger, and drilled into the ground .

When the desired founding level is reached in soil or rock, cement grout is pumped into the hollow stem of the auger. The spoil rising up the auger ensures that soft material cannot fall into the void at the bottom of the rock socket.This also flushes the base of the pile ensuring a clean contact with the bedrock.

The auger is then slowly withdrawn from the ground, bringing the soil held between its flights with it. While grout is simultaneously filling the shaft.

Once the auger has been removed from the grout-filled pile shaft, a steel reinforcement cage is immediately lowered into the liquid grout.

Various sizes and depths are possible according to design