Papyrus Press Advance Researches in Civil Engineering 2645-7229 6 4 2024 12 01 Comparative Numerical Evaluation of Helical and ‎Conventional Pile Foundations under Seismic and Wind ‎Loading Using PLAXIS 3D 1 16 250668 10.30469/arce.2025.568328.1090 EN Dima MOHAMMED Civil Engineering Department, Altınbaş University, Istanbul, Türkiye Mohsen Seyedi Civil Engineering Department, Altınbaş University, Istanbul, Türkiye Journal Article 2025 12 24 This research presents a three-dimensional numerical comparison of helical and conventional pile ‎foundations subjected to sequential seismic and wind loading using PLAXIS 3D. Eight scenarios ‎were analyzed by integrating soil stratification, pile type, and layout configuration to evaluate ‎lateral displacement, stress distribution, and bending behavior under dynamic conditions. The ‎results show that helical piles consistently outperform conventional piles, reducing maximum ‎lateral deformation by approximately 15–40%. The greatest improvement is observed in clay-‎over-sand profiles, where deeper sand confinement enhances stiffness and limits pile curvature. ‎In contrast, sand-over-clay stratifications exhibit the largest displacements due to stiffness ‎inversion and the dominance of weak deep clay layers. Wind loading applied after seismic ‎excitation further increased displacement in all cases, highlighting the cumulative effects of ‎multi-hazard loading and post-seismic soil softening. Overall, the findings provide quantitative ‎insight into soil–pile interaction in layered soils and support the use of helical piles within ‎performance-based foundation design for dynamic environments.‎ https://www.arce.ir/article_250668_d62efdfc9db75b5178687bfbbb70cd0c.pdf