Abstract:
Augered cast-in-place (ACIP) piles, also known as continuous flight auger (CFA) or augered pressure-grouted (AGP) piles, are a well-established method for installation of deep foundation elements. A current equipment constraint of ACIP piles is the largest pile diameter that can be constructed, typically around 36 inches diameter. To overcome this limitation, some ACIP contractors have begun offering deep foundations which in this presentation will be referred to as Tangent Bearing Elements (TBEs). A TBE consists of two or more ACIP piles spaced at one diameter center-to-center. The individual pile elements form a bundle which acts as a single foundation element in axial loading. This results in an efficient foundation installation method which produces equivalent-sized elements faster than traditional large-diameter bored piles. Because of their non-traditional geometry however, design engineers may be hesitant to utilize TBEs. This presentation examines the results of several bi-directional static load test programs conducted on TBEs and compares them to traditional single-element piles.