Innovative FRP reinforced UHPC floating wind turbine foundation: A comparative study

Conventional floating offshore wind turbine (FOWT) foundations, typically constructed from steel, are prone to corrosion and fatigue, resulting in high maintenance costs and limited lifespan. To address these issues, Fiber-Reinforced Polymer (FRP) reinforced ultra-high performance concrete (UHPC), referred to as FRU composites, has been proposed as an alternative due to their superior mechanical properties and high resistance to harsh marine environments. This paper presents a comparative analysis of the hydrostatic and hydrodynamic performance of FOWTs with FRU and steel foundations. The FRU-based FOWT foundation was developed based on an existing steel FOWT foundation, maintaining similar overall dimensions while adjusting wall thickness to ensure comparable stiffness in the central and side columns and equivalent strength in the buoyancy tank. Then, FOWT models were established for a 10 MW wind turbine on foundations made of FRU or steel. The results show that the FRU foundation has an enhanced capacity to resist overturning, with a center of gravity 1.67 m lower and a wind heel angle 0.8° smaller than the steel foundation. In addition, the time domain motions of FOWTs with FRU and steel foundations were examined under various loading conditions. It is found that under normal loading conditions in the 0° direction, the FOWT with the FRU foundation shows an 8.6% smaller peak surge motion and a 27.3% smaller peak pitch response compared to the FOWT with steel foundation. However, under extreme conditions, the peak surge motion of the FRU foundation FOWT increases by 2.1%, while the peak pitch response decreases by 1.6% compared to the steel foundation FOWT. These findings highlight the potential of FRU composites as a promising alternative for FOWT foundations. • FRP reinforced UHPC (FRU) composites are proposed and designed to be the foundation of an OFWT. • FRU OFWT has a larger anti-overturning moment and a better motion response. • The comparisons on pitch and roll motions of the FRU or steel OFWT depends on the wave period. • Time domain analysis demonstrates FRU OFWT has a better motion performance compared to the steel OFWT.