Precast Concrete Piles
Pre-cast R.C.C. piles are generally, of square section with chamfered corners. The section may be octagonal or circular. Better appearance is obtain in case of octagonal section and moreover reinforcement can easily be place in it. Precast Concrete Piles facilitate the driving processes, metallic shoes are use at the end 1 : 2 : 4 mix is use for normal loads and 1 : 1 : 3 mix is use for heavy loads and for driving through hard soils.
The diameter varies from 30 to 64 cm and the length varies from 4 m to 30 m. Such piles are not taper but have point lower ends. Tapering, if it has to be provide should not exceed 2 cm/m length of pile.
The function of the reinforcement is to resist the stress which will develop in the pile due to its handling, driving and loading. The reinforcement consists of longitudinal bars with spiral at he top and bottom ends. Suitable ties are provide in between them. In some cases, spiral may be provide for the whole length of the pile. Generally, these piles are cast horizontally and care should be taken that an unyielding base has been provide.
Advantage of Precast Concrete Piles
- Construct well before the execution of the work.
- Prepare by proper workmanship and if any defect remains, the same can be repair.
- They keep the reinforcement at their proper positions. The reinforcement does not get displace.
- Withstand loads only after concrete has properly cured.
- More conveniently under water.
- They are not affect by additional forces develop due to the driving of adjacent piles.
- More suitable when a portion of them is to remain expose.
Disadvantages of Pre-Cast Concrete Piles
- Difficult to handle and transport.
- Cannot be construct of exact lengths. Therefore, if additional length is to be provide. Then, the cost increases and the pile becomes weak at the joints.
- Liable to become weak due to the shocks of driving.
- Involve extra labour, time and funds and if found to be too long after driving then the extra length has got to be cut down.