Design approach for estimating soil damping due to monopile-soil interaction of an offshore wind turbine under fatigue loading

📢 Check out our newest paper in SDEE journal in the following link demonstrating a simple and efficient model approach that builds on the PISA 1D representation of the monopile foundation and soil reactions by using a kinematic hardening law to describe the monotonic and cyclic soil-structure interaction response in the springs.

💡This work comes from our experience with monopile design for OWF developments and was motivated by the limitations of the simplified methodologies typically adopted in current design practice that lead to significant soil damping underestimation and increased foundation costs. The adoption of the proposed approach can improve the reliability of soil damping used in fatigue assessments of OWTs founded on monopiles and more rigorously incorporate site-specific soil conditions, offering a practical approach for engineering design practice.

Design approach for estimating soil damping due to monopile-soil interaction of an offshore wind turbine under fatigue loading - ScienceDirect

ISFOG 2025

📢 GR8 GEO made its mark at the 5th International Symposium on Frontiers in Offshore Geotechnics (ISFOG 2025) in Nantes, France! 🌍⚙️

Our team participated with FIVE cutting-edge papers showcasing our latest innovations and insights in offshore geotechnics. From advanced numerical analyses of OWTs on suction buckets under seismic loading, spudcan penetration, offshore pipeline end manifolds on liquefiable soils and numerical validation of PISA field tests on clay to novel centrifuge experiments of OWT monopiles in saturated dense sand under storm cyclic loading, we’ re pushing the boundaries of what’s possible in the industry! 💡 

📍 "Centrifuge modelling of an OWT monopile foundation in saturated sand subjected to cyclic dynamic storm loading" by Panagiota (Yota) Tasiopoulou, Taxiarchoula Limnaiou, Lampros Sakellariadis, Jacob Chacko, Jones L., Agalianos A. and Anastasopoulos I. can be found at https://www.issmge.org/uploads/publications/132/133/ISFOG2025-51.pdf

📍 "Analyses of spudcan penetration and its effect on an adjacent offshore WTG monopile foundation" by Vasileios Drosos, Yannis Chaloulos, Panagiota (Yota) Tasiopoulou, Takis Georgarakos, Amalia Giannakou and Jacob Chacko can be found at https://www.issmge.org/uploads/publications/132/133/ISFOG2025-117.pdf

📍 "Insight into the cyclic response of OWT pile foundations in clay: Numerical simulation of PISA field tests" Panagiota (Yota) Tasiopoulou, Taxiarchoula Limnaiou, Amalia Giannakou and Jacob Chacko can be found at https://www.issmge.org/uploads/publications/132/133/ISFOG2025-52.pdf

📍 "Dynamic Soil-Structure Interaction evaluations of liquefaction-induced settlements of a Pipeline End Manifold (PLEM)" by Yannis Chaloulos, Giannakos S., Taxiarchoula Limnaiou, Charalampos Tsifis, Amalia Giannakou, Jacob Chacko, Meijer A., Vazquez Perez G. and Hoffmann C. can be found at https://www.issmge.org/uploads/publications/132/133/ISFOG2025-204.pdf

📍 "3D dynamic effective stress analyses of an offshore wind turbine on suction bucket jacket foundation under earthquake loading" by Yannis Chaloulos, Charalampos Tsifis, Taxiarchoula Limnaiou, Panagiota (Yota) Tasiopoulou, Vasileios Drosos, Amalia Giannakou and Jacob Chacko can be found at https://www.issmge.org/uploads/publications/132/133/ISFOG2025-162.pdf

Fully-Coupled cyclic time-history analyses of monopile foundations in sand

Sneak peek 📢 ! Check out our contribution to the Special Issue of Ocean Engineering: "State of Practice – Geotechnical Considerations for Offshore Wind" in the link below (limited free access until April 19th).

The paper presents the results of 3D coupled cyclic time history numerical analyses of a monopile supporting a 12 MW Offshore Wind Turbine, installed in dense cohesionless soils and subjected to a 600-s load history corresponding to the high phase of a 35-h design storm. The goal of the study is to investigate the governing mechanisms and gauge potential conservatisms or uncertainties in approaches for monopile analysis used in practice. The Ta-Ger constitutive model, implemented in FLAC3D and calibrated against site-specific cyclic tests, is used to model the complex soil response. Emphasis is placed on the effect of drainage conditions, an aspect typically overlooked in practice, although often stated as critical. Analyses show that the drainage of the system can substantially affect the response. In low-permeability soils (e.g., cohesionless soils with low-plasticity fines) widespread liquefaction may occur inducing high rotations above allowable limits. On the contrary, systems that can drain effectively within each cycle, develop moderate excess pore pressures which do not jeopardize performance. Current design procedures are often unable to accurately capture these effects possibly leading to either conservative or unconservative outcomes. Suitably validated advanced numerical analyses can be used as complementary tools to standard methods to assess these uncertainties.