Cellular Raft as a Foundation System for Onshore Wind Turbines

Abstract Onshore wind turbine foundations withstand significant overturning moments while ensuring structural integrity and cost-effectiveness. Conventional gravity-based foundations reach the resistance by using large volumes of reinforced concrete, leading to high construction costs and considerable embodied carbon emissions. This study examines the feasibility of a cellular raft foundation as an alternate support system for a Vestas V80 2 MW wind turbine within the geotechnical conditions of the Gabal El-Zeit Wind Farm in Egypt. A framework for analytical overturning capacity and three-dimensional finite-element calculations utilizing PLAXIS 3D was developed to assess the structural and geotechnical performance of the proposed foundation in comparison to the conventional gravity-base foundation. Parametric analyses were performed to investigate the impact of foundation diameter, tower weight, and backfill soil characteristics on overturning resistance. The findings indicated that the cellular raft foundation shows substantially greater overturning resistance compared to the conventional foundation of identical diameter, with analytical enhancements surpassing 50% and numerical assessments revealing an approximate 37.5% increase in ultimate overturning capacity. The improved performance is attributed to the stabilizing contribution of the soil infill and the developed structural efficiency of the cellular configuration. The parametric analysis indicated that foundation diameter is the primary factor influencing overturning capacity, whereas tower weight and backfill density demonstrated rather minor impacts. The proposed approach reduced the estimated material-related foundation cost by roughly 21% by significantly lowering excavation volume, concrete usage, and reinforcement needs. The results indicate that cellular raft foundations offer a structurally efficient, economically viable, and potentially more sustainable alternative to traditional gravity-based foundations for onshore wind turbine applications.