Shape dependent wave force and bending moment of offshore wind substructure system

In this study, analytical study to optimally arrange the multi-piles and the concrete base parts of the steel-concrete hybrid substructure for offshore wind was carried out. In order to minimize wave force and wave-induced bending moment subjected to the substructure system, diffraction and structural analysis were carried out for three types of hybrid substructure to the concrete base height. As the results of this study, wave-induced bending moment of hybrid substructure indicated about 20.6 ~ 24.7 % level comparing with the mono-pile for the extreme wave condition. Wave-induced bending moment at the foundation pile head was similar with the mono-pile for the concrete base height 8.0 m case. Therefore, in order to certify the same structural safety for hybrid substructure with the mono-pile, it was found that the critical height of the concrete base was the 8.0 m.