PSI - Issue 84

Luca Vené et al. / Procedia Structural Integrity 84 (2026) 544–551

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The comparison between the results in Cesaro et al. (2024) and those inferred via the proposed procedure shows a overall good agreement in both shape and extent confirming its robustness, accuracy, and consistency in capturing the group interaction mechanisms and the performance-based response of pile foundations. 4. Conclusions In the present study, a new procedure for the evaluation of performance-based interaction domains for eccentrically loaded pile groups was developed. Each pile was modeled as an axially deformable element, and the surrounding soil was represented as an elastic half-space following the Mindlin (1936) formulation. The load-settlement response of each pile–soil system was obtained through a Boundary Element Method (BEM) analysis and incorporated into a hyperbolic load–settlement law, capturing the nonlinear behavior of individual piles while maintaining a consistent representation of the soil–pile system. Pile–pile interactions were explicitly considered through interaction coefficients derived from the superposition of soil displacement fields. This allowed the model to account for group effects under the assumption of spherical hinges at the pile cap, enforcing compatibility of displacements and rotations while neglecting bending moments at the pile heads. The resulting framework reproduces the overall response of the pile group in a physically consistent and numerically stable manner. The proposed procedure was then validated against results available in the literature (Cesaro et al., 2024). The comparison showed good agreement between the results obtained using the proposed procedure and those reported in this Ref., confirming its accuracy in evaluating both ultimate capacity (capacity-based) and serviceability (performance-based) conditions. This unified and robust approach represents a significant step toward a performance-based design of pile-supported foundations, ensuring both accuracy and versatility in practical geotechnical engineering applications. Acknowledgements The authors wish to thank Satap S.p.A. (Turin, Italy), part of the ASTM Group, for providing the data used in this study and for supporting the industrial PhD program. References Caputo, V., Viggiani, C., 1984. Pile foundations analysis: A simple approach to nonlinearity effects. Rivista Italiana di Geotecnica, 18(1), 32–51. Cesaro, R., Di Laora, R., Iodice, C., Mandolini, A., 2024. Interaction domains for capacity- and performance-based design of pile groups. Acta Geotechnica 19, 4695–4714. Di Laora, R., de Sanctis, L., Aversa, S., 2019. Bearing capacity of pile groups under vertical eccentric load. Acta Geotechnica 14(1), 193–205. Di Laora, R., Iodice, C., Mandolini, A., 2022. A closed-form solution for the failure interaction diagrams of pile groups subjected to inclined eccentric load. Acta Geotechnica 17, 3633–3646. Franza, A., Sheil, B., 2021. Pile groups under vertical and inclined eccentric loads: Elastoplastic modelling for performance-based design. Computers and Geotechnics 135, 104092. Gorini, D.N., Callisto, L., 2022. Generalised ultimate loads for pile groups. Acta Geotechnica 17, 2495–2516. Mindlin, R.D., 1936. Force at a point in the interior of a semi-infinite solid. Physics 7(5), 195–202. Poulos, H.G., 1968. Analysis of the settlement of pile groups. Géotechnique 18, 449–471. Poulos, H.G., Davis, E.H., 1980. Pile Foundation Analysis and Design. John Wiley & Sons, New York. Rosati, A., Gaudio, D., Di Prisco, C.G., Rampello, S., 2023. Use of interaction domains for a displacement-based design of caisson foundations. Acta Geotechnica 18, 445–468.

The MathWorks Inc., 2025. MATLAB R2025b. Natick, Massachusetts. Viggiani, C., 1999. Fondazioni. Hevelius, Benevento, pp. 426-427