ACPs have long been a favorite foundation system of geostructural engineers. They provide extremely high axial and lateral resistance and can be installed without any vibration disrupting surrounding buildings.
Why Auger-Cast Piles?
Auger-Cast Piles offer heavy loading resistance coupled with low costs, but can only be installed in areas with soft, alluvial soils. ACPs are typically installed in urban environments but can be installed for any new construction requiring sturdy deep foundations.
ACPs are typically used in foundation systems requiring 70 to 300 kips of pile compressive capacity, primarily in new construction, such as multistory buildings or parking garages. As stated earlier, they are preferred in urban environments where vibratory or noise disruption is not allowed.
How it's done
A crawler crane with a drill motor connected to a power unit is used to power the continuously flighted auger to drill into the ground. Earth spoils are brought to the surface by the flights and removed while drilling. Once the tip of the auger has descended to the bottom of pier elevation, grout is pumped into the top of the auger and through its hollow center. The auger is slowly lifted from the newly drilled hole as grout is pumped. Once the auger is clear of the hole, a rebar cage is dropped in to reinforce the pile.
ACPs are a tried and true high capacity foundation. They can be installed with virtually no impact on surrounding areas. They provide high axial resistance and can be design to resist lateral loads due to earthquakes.
Chris-Hill has been installing ACPs for over 20 years. Many of the structures in the greater Memphis area are founded on Chris-Hill auger-cast piles.