Design of deep penetration piles for ocean structures

Ocean structures for oil development have been constructed, or planned for construction, on continental shelves off 60 countries and in water as deep as 840 ft. Descriptions of four significant structures, in the Gulf of Mexico, Cook Inlet, North Sea, and Persian Gulf illustrate design and construction features of pile foundation systems currently used offshore in areas of severe environmental conditions. Pile size selection is dominated by substructure design considerations. Pile lengths to develop required axial capacities are estimated from static analyses using boring and test data. Designing pile wall thickness requires difference equation analyses to predict bending stresses resulting from wave and other lateral forces. Estimates of vertical and horizontal pile movements, as required to assist substructure design, are also obtained using difference equation solutions. Pile installation is primarily achieved by driving, using hammers with rated energies up to 600,000 ft-kips. Research needs to support the rapidly advancing development of ocean structures are examined.