Jacket structures are used to support offshore facilities, such as those to support oil and gas reservoir facilities and for renewable energy to support substations and wind turbine generators. Most jackets are connected to the seabed using open-ended steel tubular piles. The design methods for the capacity of these open-ended piles were calibrated to the measured capacity of piles in the engineering pile database. The capacity of a pile is estimated by addition of the external shaft friction and base capacity. Using a one-dimensional finite element method, which models the response mechanisms of the supporting components, a detailed analysis was made of a selection of these pile design methods. It was found that, in terms of total capacity and distribution between friction and end bearing, some methods were better suited to clays while others were more applicable for sands. In cases where the capacity distribution was poor, an assessment was performed to determine if the distribution could be improved by applying factors to the shaft and base resistances. The work shows that the interrelationship of shaft and base capacities is not direct, and depends on the characteristics of the pile and soil.
Trevon M. Joseph and Guy T. Houlsby
Keywords: finite-elements, open-ended-piles, design methods, pile response, capacity
Publisher: DFI