Conceptual Axial Stress-Strain Behavior Assessment of Drilled Displacement Piles Using Full-Scale Load Tests Database-Video

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Video Summary

Abolfazl Islami presented a data-driven assessment of the axial stress–strain behavior of drill displacement (DD) piles. Using 40 full-scale case histories from around the world, the study normalized load and settlement by pile cross-sectional area and length, allowing piles of different sizes to be compared. The database included pile dimensions, soil conditions, CPT profiles, and measured load–displacement responses. The analysis examined ultimate capacity, stiffness, yield behavior, toughness (energy absorbed), and resilience (energy recoverable during unloading). A settlement of 5% of pile diameter and the 80% Brinch Hansen criterion were identified as useful indicators of ultimate load. Results suggested that toughness increases with embedment depth and soil strength, but decreases as pile diameter increases. Compared with other foundation types, DD piles showed strong energy absorption and resilience. Islami concluded that stress–strain assessment can support more consistent foundation comparisons and performance-based design, while larger databases could reduce uncertainty and improve efficiency and sustainability.

Keywords

drill displacement piles

axial stress-strain behavior

pile capacity and stiffness

toughness and resilience

foundation performance comparison