Driven Precast Piles.

Driven precast piles can be used in areas where the soils, through which the pile is to be driven, are relatively soft and unobstructed and where the length of pile required can be determined to a reasonable accuracy. The piles can be cast to any suitable cross-section, i.e. square, rectangular, circular, hexagonal, etc. The shape and protection to the point of the pile is determined from the end bearing requirements and driving conditions. The pile head and the reinforcement are designed to take account of the pile-driving impact loads. Some disadvantages of this method of piling are that the pile can be damaged in a location out of sight during driving and the pile can be displaced if it meets an obstruction such as a boulder in the ground. In addition the accuracy of the estimated length is only proved on site and short piles can be difficult to extend and long piles can prove to be expensive and wasteful. A further disadvantage is the relatively large rig required for driving and the need for hardstandings that are often required to provide a suitable surface for the pile-driving plant.