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

PPT Presentation

Pdf Summary

The presentation develops a conceptual stress–strain framework for evaluating the axial behavior of drilled displacement (DD) piles. It argues that converting load–displacement test results into normalized stress–strain curves can support more consistent comparisons among foundation types and improve design assessment.<br /><br />The study compiles 40 full-scale static load tests from multiple countries, covering Fundex, Atlas, Omega, and Berkel D piles. The database includes piles 356–650 mm in diameter and 7–19.5 m deep, installed in clay, sand, and mixed deposits. The researchers examine load–displacement records and assess several criteria for estimating ultimate pressure. The 5% breadth and Brinch-Hansen 80% criteria are selected for further analysis because they are straightforward and applicable across the cases.<br /><br />The framework also evaluates energy-related performance. Resilience represents energy absorbed in the elastic range, while toughness represents energy absorbed up to a specified displacement or failure threshold. The analysis indicates that longer, narrower DD piles in mixed soils tend to have higher toughness.<br /><br />The presentation compares DD pile stress–strain behavior with that of spread footings, helical piles, driven piles, and drilled shafts. It concludes that a database-driven, normalized stress–strain approach can help assess strength, stiffness, displacement, and energy absorption while addressing uncertainty in foundation design. DD piles are presented as an efficient and potentially sustainable foundation option, and energy-based assessment as a useful contribution to designing resilient foundations.

Keywords

drilled displacement piles

stress-strain framework

load-displacement tests

ultimate pressure

energy absorption

foundation design

normalized curves

static load tests

toughness

resilience