The data of Comparative Bearing Behavior of Double Layer Transition Segments for Composite Bucket Foundations Serving Offshore Oil and Gas Platforms and Wind Turbines

The foundations of offshore oil and gas platforms are subject to large vertical loads, whereas those of offshore wind turbines are subject to large overturning moments. Conventional support structures find it difficult to satisfy both requirements simultaneously. To address this conflict, the concept of a double-layer transition segment for composite bucket foundations, which can be used by both types of facility, is proposed. Using a combination of theoretical analysis and finite-element simulation, three configurations of the transition segment are compared: arc-shaped (AS), arc-shaped double-layer (AD) and folded-line double-layer (FD). These are compared under axial, horizontal, bending and combined loading, followed by a soil-structure interaction analysis. The axial load follows the parallel-stiffness rule, with the outer and inner layers sharing approximately 55% and 45% respectively, as predicted by a modified shell-membrane theory. The AD configuration achieves the lowest peak stress and the most uniform stress distribution. Under horizontal loading, its peak tensile stress (0.88 MPa) is only 31.4% of the FD value. Under combined loading, 20.8% lower than that of AS, with a coefficient of variation that is 13.3% lower than the AS configuration. When considering soil-structure interaction, the AD configuration still exhibits the smallest displacement and inclination. The AD configuration is therefore recommended, as it combines the stress dispersion of the arc profile with the stiffness regulation of the double-layer system.