Improved load capacity of a hybrid bucket foundation for offshore structures in sand

Abstract

As offshore structures grow larger with increasing depth and distance from shore, their foundations must increase in strength owing to the larger supporting capacity needed. This requires new approaches to ensure economic and reliable infrastructure. Suction bucket foundations (SBFs) are viable options in offshore settings owing to their easy installation and affordability; however, they suffer from performance limitations. Recently, a hybrid bucket foundation (HBF) design has been proposed in which a suction bucket is connected to an underlying mat to increase load capacity. However, the behavior of this design under combined vertical, horizontal, and/or moment loads is not yet well understood. In this study, we used centrifuge models to investigate the behavior of HBFs and conventional SBFs under different load conditions. The results demonstrated the feasibility and superior performance of HBFs. In particular, the bearing capacities of HBFs under vertical and combined loads were similar to 1.91 and similar to 1.82 times higher, respectively, than those of SBFs within the testing ranges. These findings indicate that the mat component attached on top of the hybrid bucket unit significantly improves the bearing capacity.