Axial Load-Displacement Relationship and CPT Correlation for ACIP Piles in Texas Gulf Coast Soils: Fid-Bau Portal

Axial Load-Displacement Relationship and CPT Correlation for ACIP Piles in Texas Gulf Coast Soils

Vipulanandan, C. / Tand, Kenneth E. / Kaulgud, S.

Non-displacement augered cast-in-place (ACIP) piles are being increasingly used in construction because they can be installed relatively rapidly with minimum environmental impact and have the flexibility to quickly adjust pile length for varying soil conditions as compared to the other deep foundation systems. Due to lack of understanding of ACIP pile behavior, in many instances, the design capacity of the ACIP pile must be verified by performing one or more full-scale load test on site before installing the production ACIP piles. Hence there is a need to better quantify the performance of ACIP piles in various soil conditions. In this study the load-displacement behavior of eight full-scale ACIP piles with diameters in the range of 410 to 460 mm was investigated. The length of the piles varied from 9.1 to 21.3 meters and the measured pile capacities varied from 1520 to 2670 kN. A two-parameter non-dimensional hyperbolic relationship to represent the non-linear load-displacement behavior of ACIP piles has been verified with the full-scale test data available from eight tests performed in clay, sand and mixed soil profiles in the Texas Gulf Coast region. The parameters required for the model were related to the in-situ soil properties obtained from the CPT tests and the pile dimensions. The ultimate load capacity predicted by the hyperbolic model was higher than that of the LPC method. The ratio of maximum applied load during the load test to predicted ultimate capacity using the hyperbolic relationship varied from 0.78 to 0.97 with an average of 0.86. The displacement needed to mobilize half of the ultimate pile capacity of the ACIP piles was in the range of 0.35 to 1.5% the diameter of the pile.