WindFloat FC: A Four-Column Floating Wind Turbine Foundation - Part II - Structural Design and Analysis

Abstract As the floating wind industry transitions from pre-commercial to utility-scale projects, wind turbine generator (WTG) ratings of 15 MW and beyond are increasingly being considered. With this growth, some WTG original equipment manufacturers (OEMs) are expressing a preference for platforms operating in the stiff-stiff eigenfrequency regime, where the first coupled tower-platform frequency is above the nominal 3P frequency of the WTG. Central column platform designs, such as the WindFloat FC, are emerging as optimal solutions to achieve this new requirement. WindFloat FC was introduced by Principle Power to address the growing demands of upcoming utility-scale floating offshore wind projects. In addition to its technical advancements, the WindFloat FC emphasizes standardization and industrialization to streamline fabrication, reduce costs, and accelerate deployment at scale. This paper provides an in-depth look at the structural design and analysis of the WindFloat FC platform for a given case study, with a focus on three key aspects. First, the structural design methodology is described, highlighting strategies utilized to de-risk the primary structure. Second, it introduces a methodology for calculating the coupled eigenfrequencies of the wind turbine and platform. Lastly, structural analyses are performed to evaluate the platform’s performance under extreme and operational conditions dictated by metocean requirements, ensuring its long-term resilience and reliability. This work is complemented by another paper in these proceedings, which delves into the Global Sizing and Global Performance Analysis of the WindFloat FC platform.