Semi-submersible foundations are the most common type for floating wind turbines due to their stable motion and mature technology. To reduce costs for larger-scale applications, this study explores using steel-concrete composites. An economical foundation concept was designed for a site in the South China Sea to support a 20MW-class turbine, aiming for low steel consumption. A rapid two-step structural strength assessment was implemented. First, a global finite element model used plate-beam elements for steel and equivalent plates for concrete to evaluate overall strength. Second, critical concrete areas were analyzed in detail using a sub-modeling technique with a refined solid-element model. Results show the design has satisfactory motion performance, with equivalent steel consumption effectively controlled below 330 ton/MW. Strength verification confirms both steel and concrete components meet safety standards. This research provides valuable insights for developing and assessing large-scale steel-concrete composite floating wind turbine foundations.
Wang et al. (Sun,) studied this question.