Compacted Concrete Piles
(also known as Compacto or Franki type Piles)

Advantages

• By driving and subsequently withdrawing a heavy-walled tube as construction progresses, no danger of contamination of the finished pile exists.
• Application of high energy blows (up to 200,000 joules) in forming the expanded base has the double advantage of providing a very dense concrete bulb through which the column loads are distributed, as well as compacting the surrounding soil, thereby increasing its bearing capacity and shear strength.
• Additional carrying capacity is developed during construction of the shaft by expelling compacted concrete out against the already compressed soil with blows up to 40,000 joules of energy.
• Upgrading of soil properties at each pile location results in minimizing effects due to variations in soil type and density over the entire site.

Disadvantages

• Depths generally limited to 15 m and most suited for granular soils.
• Vibrations during installation can be excessive.
• Due to being a displacement type pile site heave can be appreciable depending on pile spacing and insitu density.
• Batter cannot exceed 1 in 4.

General

• Three standard sizes are normally installed, namely 400 mm, 500 mm and 600 mm diameter.
• Design load capacity up to 800 Kn, 1,100 Kn and 1,500 Kn, respectively.
• Most cost efficient when loaded to maximum design load.