Comparisons of hydroelastic behaviors of a pontoon-type VLFS and of a column-supported VLFS in waves

Abstract

A very large floating structure (VLFS) for various applications such as a floating airport is generally classified into a pontoon-type, a column-supported type or a semisub-type. It is expected that large elastic deformations of such structures are induced by the dynamic effects of waves, because the horizontal dimension is extraordinary large compared to the thickness of the structures or of their upper deck. However, there exist few researches as to how the structural type of a VLFS affects its elastic deformations in waves. Recently, we have developed a prediction method of hydroelastic behavior of VLFSs. In this paper, the characteristics of wave-induced elastic deformations of a pontoon-type VLFS and those of a column-supported VLFS are compared using the developed method. It is found that the characteristics can be categorized in terms of the area ratio of the water surface area of the corresponding VLFS to the plain projected area of the whole structure rather than be categorized in terms of the structural type. This, in turn, implies that the relevant parameter that determines the elastic deformations of a column-supported VLFS is not the number of columns but the area ratio