On the validity of classical beam theory for the analysis of thin-walled piles under lateral loading
On the validity of classical beam theory for the analysis of thin-walled piles under lateral loading
Open-ended steel piles connected by catenary mooring lines are one of the solutions for anchoring floating wind turbines. The piles are subjected to horizontal loading and the understanding of the pile behaviour in interaction with the foundation soil is essential for ensuring structural safety and optimizing design. To further understand this behaviour, an experimental campaign was conducted using a medium-scale model of a short open-ended pile (325 mm diameter, 2 m embedment) in dense sand, as part of the SAM-WT GEOLAB project. The pile was tested under monotonic lateral loading and instrumented with nine pile-head displacement sensors and 32 strain gauges along its length. The behaviour of a pile under lateral loading is usually analysed using the p-y curves method, which relates the soil lateral reaction on the pile shaft to the pile lateral displacement. Experimentally, the p-y curves can be derived from instrumentation of the pile shaft using strain gauges and the application of classical beam theories such as Euler-Bernoulli. However, this approach shows limitations when applied to thin-walled piles, as the simplified structural assumptions may not capture the real behaviour. This paper assesses the relevance and limitations of the classical approach to behaviour analysis. This is proposed here through analysis of experimental data and 3D finite element analyses of the pile, evaluating classical beam theory and the equivalent flexural rigidity approach. The results highlight that conventional modelling approaches fail to capture localized effects such as stress concentrations and cross-sectional ovalisation. These findings underscore the need for improved modelling strategies that can accurately represent the behaviour of thin-walled piles.
Lucas Vinicius Coelho Alves da Silva; Orianne Jenck; Christophe Dano; Rami Chalhoub; Joaquin Liaudat; Alexander Kochnev; C. N. Abadie; Fabien Szymkiewicz; H. Zachert
11th International Conference on Physical Modelling in Geotechnics (ICPMG2026)
Session 6: Onshore and offshore foundation systems
https://doi.org/10.53243/ICPMG2026-208