What Are Concrete Piles?

Cast-In-Place Piles

• Cast-in-place or CIP piles are formed usually using an augur. The augur drills a cavity into the earth for the pile, keeping the soil in a plugged hollow stem. The cavity is filled with grout, forming the pile. Using vibrations different reinforcements are placed into the grout while it's still malleable. CIP piling requires no pile drivers and often no steel casing, reducing cost and environmental damage caused by vibrations.

Precast Piles

• Precast piles are reinforced using cages or tension wires. Cage designs vary including hoops, spirals and horizontal bars joined by vertical connectors. Tension wires better support stress on concrete piles by preventing cracks from opening. Pile connectors or splices add tensile strength to concrete piles. One method includes connecting steel dowels from one pile to corresponding holes drilled in the adjoining pile with epoxy or grout. Another method uses pointed ends covered in steel which fit into the pile below it.

Advantages

• Precast concrete piles are popular essentially because they are better suited for mass production. Design standardization and rapid production time are maintained while producing quality concrete piles. Piles are resistant to transportation cracks and relatively simple to install including pile caps, which join each part of a pile, geared towards ease of use. Even in weak soils, precast concrete piles can support heavy loads. For additional strength these piles can be spliced.

Shapes

• The shape in which a concrete pile is precast determines its characteristics. Different shapes handle different stresses caused by load type. Load types include temporary, permanent, repetitive and transient. Circular piles provide high durability, stability and visual appeal but are more expensive and have surface defects. Pentagon and octagon piles also result in defects due to their complex shape. Other shapes such as the star and rectangle are difficult to orient correctly but offer greater bending resistance.