Precast Concrete Piles.

These piles include conventionally  reinforced concrete piles and prestressed concrete piles.  Reinforced concrete piles are constructed with an  internal reinforcement cage consisting of several longitudinal bars and lateral ties, individual hoops, or a spiral. Prestressed concrete piles are constructed using steel rods or wire  strands under tension as reinforcement.  Since the concrete is under continuous compression, transverse cracks tend to remain closed; thus, prestressed piles are usually more durable  than conventionally reinforced  piles.   Influential factors  for precast concrete piles include splices and steel points.

(a)   Various splices are available to connect concrete piles.   The splice will provide the tensile strength required during driving when the resistance to driving is low.  Figure 1-2a illustrates the cement-dowel splice.  Refer to “Foundations” (Pile  Buck Inc. 1992) for additional splices.

(b)  Special steel points can be attached to precast precast piles during casting of the piles and include steel H-pile tips or cast steel shoes (Figure 1-2).

Figure 1-2.  Concrete pile splice and boot.