Numerical Approaches Aimed at a Sustainable Design: The Case of Wind Tower Foundations

The current effort towards the progressive switch from carbon-based to renewable energy production is leading to a relevant spreading of both on- and off-shore wind turbine towers. Regarding reinforced concrete shallow foundations of onshore wind turbine steel towers, possible reductions of reinforcement obtainable by employing steel fibre-reinforced concrete (SFRC) may increase their sustainability, speed of erection, and competitiveness. At the same time, there is a strong need to extend the life of foundations erected more than 15 years ago, originally designed for only 20 years. The paper presents a numerical investigation based on the results of a research programme in progress at Politecnico di Milano with ENEL, concerning the reinforcement with steel fibres of concrete shallow foundations embedded in a sandy soil subjected to both cyclic and monotonic loading. The approach takes advantage from a careful modelling of soil-structure interaction to highlight the safety margins correlated to conventional design and shows how the multi-directional resistance of SFRC allows a significant reduction of resources, preventing any brittle behaviour correlated to a reinforcement reduction.