Full-Scale Load Testing and Extraction of Augered Cast-in-Place (ACIP) Piles in Central Florida-Article

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The study reports a full-scale demonstration of augered cast-in-place (ACIP) piles in central Florida, conducted to improve understanding of their installation, quality control, and structural performance. Seven instrumented piles, 457 or 610 mm in diameter and installed in mostly sand and silty sand, were monitored and tested: two in axial compression, two in tension, and two laterally. A seventh pile was extracted for inspection.<br /><br />Automated and manual monitoring produced broadly consistent grout-volume measurements. Thermal integrity profiling using embedded wires and removable probes gave comparable results; wires provided more continuous readings, while multiple sensors on a reinforcement cage were better suited to assessing pile geometry and alignment. The extracted pile showed no necking or inclusions. Its average diameter was 494 mm, about 8% above its 457 mm nominal diameter.<br /><br />Compression tests reached maximum loads of approximately 3,300 kN and 3,980 kN. Analysis of embedded strain-gage data showed that the Incremental Rigidity method generally tracked soil-strength variations more plausibly than the Constant Modulus and Tangent Modulus approaches, although some instrumentation failures required assumptions. Tension capacities were estimated at 1,824 and 2,538 kN; the authors note that unsleeved center bars may crack piles and inflate measured head displacement through bar elongation. Lateral tests established allowable capacities of about 83 and 107 kN under the applied displacement criterion.<br /><br />At 28 days, grout strength averaged 52.3 MPa, exceeding the specified 41.4 MPa. The findings support the feasibility of ACIP piles for structural applications and highlight the importance of reliable installation records, redundant instrumentation, appropriate thermal-sensor arrangements, and sleeving reinforcement bars during tension testing.

Keywords

augered cast-in-place piles

ACIP piles

full-scale demonstration

installation quality control

structural performance

thermal integrity profiling

axial compression testing

tension testing

lateral load testing

grout strength