Sahin Caglar TunaTuna, Şahin Çaglar2025-10-0620252075-530910.3390/buildings151527232-s2.0-105013271471http://dx.doi.org/10.3390/buildings15152723https://gcris.yasar.edu.tr/handle/123456789/6295https://doi.org/10.3390/buildings15152723This study presents a numerical and experimental evaluation of axial load transfer mechanisms in deep foundations constructed in stratified cohesive soils in & Idot,zmir T & uuml,rkiye. A full-scale bi-directional static load test equipped with strain gauges was conducted on a barrette pile to investigate depth-dependent mobilization of shaft resistance. A finite element model was developed and calibrated using field-observed load-settlement and strain data to replicate the pile-soil interaction and deformation behavior. The analysis revealed a shaft-dominated load transfer behavior with progressive mobilization concentrated in intermediate-depth cohesive layers. Sensitivity analysis identified the undrained stiffness (Eu) as the most influential parameter governing pile settlement. A strong polynomial correlation was established between calibrated Eu values and SPT N60 offering a practical tool for preliminary design. Additionally strain energy distribution was evaluated as a supplementary metric enhancing the interpretation of mobilization zones beyond conventional stress-based methods. The integrated approach provides valuable insights for performance-based foundation design in layered cohesive ground supporting the development of site-calibrated numerical models informed by full-scale testing data.Englishinfo:eu-repo/semantics/openAccessdeep foundations, performance-based design, load transfer mechanism, finite element modeling, strain energy analysis, soil stiffness correlationDESIGN, PILEDeep FoundationsFinite Element ModelingPerformance-Based DesignLoad Transfer MechanismSoil Stiffness CorrelationStrain Energy AnalysisArticle