<p>This study developed an integrated displacement- and energy-based interpretation framework for evaluating the axial performance of deep foundations from full-scale field tests. The framework was applied to two instrumented compression load tests on bored and barrette piles in İzmir, Türkiye. A field-calibrated energy formulation was established by relating measured load–settlement energy to an idealized elastic reference energy through the dimensionless coefficient β. The same formulation was used to convert serviceability and ultimate displacement limits into energy-equivalent thresholds. Strain-gauge measurements were used to derive axial load transfer, segmental shaft resistance, base resistance, and back-calculated undrained shear strength. The results showed that the barrette pile exhibited shaft-dominated behavior, with approximately 92% of the applied load resisted by skin friction. It also showed higher cumulative energy absorption and more pronounced stiffness degradation than the bored pile. A site-specific correlation between standard penetration test N₆₀ and back-calculated undrained shear strength was developed and checked against cone penetration test-based estimates. The proposed framework links energy metrics, stiffness degradation, strain-gauge-derived load transfer, and soil strength calibration within a single field-calibrated performance assessment approach for deep foundations.</p>