Session: 10-02-02 Bucket Foundations and Suction Piles

Submission Number: 174197

Simplified Design Methods for Hybrid Monopile-Bucket Foundations for Offshore Wind Turbines 

The continued upscaling of offshore wind turbines to 15–26 MW and expansion into deeper waters have pushed conventional monopile foundations to their limits, with weights approaching 2,500 tonnes that exceed the capacity of 40–50% of European installation vessels. Hybrid monopile–suction bucket foundations offer a promising solution by enabling staged installation and improving load distribution; however, their dual-foundation nature creates a complex four-dimensional design space that requires computationally intensive three-dimensional finite element analyses.

This study presents a set of simplified design methods to streamline the design process through three key contributions: (1) a regression-based approach using only three strategically selected 3D FE simulations to predict lateral capacity and initial stiffness across the design space, reducing computational requirements while maintaining high accuracy; (2) application of the INFIDEP tool for rapid design, achieving computation times two orders of magnitude faster than conventional software; and (3) characterization of lateral p–y response in clay revealing three distinct depth zones that govern soil-structure interaction mechanisms. The identified depth zones—bucket-dominated zone, transition zone, and monopile-dominated zone—provide essential insights for developing simplified beam–spring models suitable for integrated structural analyses. Together, these methods offer practicing engineers an efficient and accurate approach for preliminary sizing, optimization, and structural assessment of hybrid monopile–bucket foundations.

Presenting Author: Henry Gunawan Norwegian Geotechnical Institute

Presenting Author Biography: Henry Gunawan is a PhD Fellow at the Norwegian Geotechnical Institute (NGI) as part of the POSEIDON MSCA Doctoral Network program. His research focuses on developing design procedures for hybrid offshore wind turbine foundations. He holds an M.Sc. in Civil Engineering from Delft University of Technology and a B.Sc. in Civil Engineering from Bandung Institute of Technology. Prior to his PhD, he worked as a Geotechnical Engineer at Seaway7, specializing in offshore foundation installation and applying machine learning to geotechnical data analysis.

Authors:

Henry Gunawan Norwegian Geotechnical Institute
Nallathamby Sivasithamparam Norwegian Geotechnical Institute
Zhongqiang Liu Norwegian Geotechnical Institute
Yutao Pan Norwegian University of Science and Technology