Uplift Capacity and Displacement of Pre-Bored PC Piles in Undrained Soils

This study aims to present interpretation recommendations to aid in the design of pre-bored PC piles in undrained soils, along with preliminary results for model factors to characterize model uncertainty. Measured capacities are estimated from the load-displacement curves using six interpretation methods, each assessed by employing the L2 method as a normalizing criterion. Predicted capacities are calculated via the α and β methods using analysis parameters for drilled shafts and are compared with measured capacities. Results show mean normalized capacities ranging from 0.45 to 1.60, with 6.4 to >43.9 mm displacements. A comparison of load-displacement behaviors reveals that pre-bored PC piles require greater displacements to mobilize the capacity than drilled shafts, driven piles, and barrette piles. The analysis highlights an overprediction of side resistance. Model factors, defined as the ratio of measured to predicted capacities, can calibrate resistance factors for reliability-based design.