STEEL JACKET STRUCTURES FOR THE NEW EKOFISK COMPLEX IN THE NORTH-SEA

This paper describes novel design aspects of two steel jacket structur es which have recently been installed in the Ekofisk offshore oil comp lex in the Norwegian sector of the North Sea, The design had to accomm odate the effects of increasing water depth over the life of the struc tures as well as significant movements within the founding sea-bed soi ls resulting from extraction-related subsidence, Other unusual aspects of the project included dealing with wave diffraction effects from a large nearby tank structure, the incorporation of a significant number of cast steel nodes (including the world's largest cast leg node) int o jacket fabrication, and special aspects of follow-on engineering res ulting from fabrication site queries.