SPECIALLANDMARKS :ISSUE C O V E R S T O R Y ACIP piles being installed at the Revel Casino in Atlantic City, NJ The Evolution of Augered Cast-in-Place Piles In 2013, Augered Cast-in-Place (ACIP) piles are a mature foundation technology throughout the United States. General guidelines for the design and construction of ACIP piles are available along with numerous references for design in specific North American geologies. In fact, the current generation of contractors and geotechnical practitioners might view ACIP piles as just another deep foundation option to be considered, along with driven piles, drilled shafts and others. This acceptance has developed, however, over a 60-plus year period. The term, Augered Pressure-Grouted (APG) pile is often used when referring to ACIP piles because the piles emerged out of construction processes at the Intrusion-Prepakt firm in the late 1940s. The company’s specialty was pressure grouting and pre- placed aggregate concrete. The grouting was typically accomplished by driving a pipe to a target level and then injecting grout under pressure. In some soil conditions, it was necessary to use an auger to reach the desired grouting depth. In these circumstances, the grout pipe was driven beside the auger and grout was pumped as the auger was withdrawn. The grout pipe was then withdrawn as well. This was the genesis of the APG, or ACIP pile, and many piles were installed using this technique. Patent, Licenses The patent application, “Method for Forming Piles” was filed by Raymond Patterson of Intrusion-Prepakt in 1951, and the patent was granted in 1956. The process was eventually modified when a suitable hollow-stem auger was developed. Licenses were granted to the Lee Turzillo Contracting Company and Berkel & Company Contractors, Inc. in the late 1950s. Each of the three companies AUTHORS coined their own terms for the piling process: “Pakt-In-Place” for Intrusion-Prepakt, “Auger Pressure-Grouted” for Berkel and “Augercast” for Turzillo. Over time, “Augercast” was frequently used as a generic term for the system. The installation of these piles was, and still is, a highly nuanced process; “contractor dependent” is a term often seen today. Intrusion-Prepakt, Berkel and Turzillo all had personnel who were part of the original group that developed the system and who appreciated the craftsmanship involved in forming sound piles. Early installation platforms were wagon or truck-mounted, and augers were advanced by relatively low-torque power units of about 15,000 ft-lbs (20.3 kN-m). Leads were mounted on mechanical cranes that made it difficult to retract the auger smoothly, and grout was placed with pneumatic pumps. Masonry sand was used in the grout (to allow the grout to be pumped with the fairly low-power pneumatic powered piston pumps), and grout was batched on site from bagged cement, fly ash and a grouting agent. The use of the fine masonry sand limited the achievable compressive strength to typically about 3,000 psi (20.7 MPa). The construction of 400 to 500 linear ft (122 to 152.5 m) of piling in a single day was considered quite an accomplishment. The piles were generally 12 in to 16 in (0.3 m to 0.4 m) diameter with short lengths and of relatively low capacity. The contractors installing ACIP piles worked continuously to address these issues through the development of improved equipment and processes. 1970s and 1980s: Transitional Period The level of ACIP pile activity increased steadily in the early 1970s, although they were still being used primarily where loads were fairly modest or where substantial uplift resistance was required. Willie M. NeSmith, P.E. (retired), Alan Roach, President, and W. Morgan NeSmith, P.E., Chief Geotechnical Engineer, Berkel & Co. Contractors, Inc. 12 • DEEP FOUNDATIONS • NOV/DEC 2013
