Limit State Design in DNV96 Rules for Submarine Pipeline Systems: Background and Project Experience

摘要

This paper discuss the safety philosophy and limit state design methodology adopted in the new revision of Det Norske Veritas (DNV) "Rules for Submarine Pipeline Systems". The new Rules completed late 19% (denoted DNV'96 in the following) constitutes a complete revision of the previous Rules from 1981 and provide a significant step forward for pipeline design and operation. DNV'96 adopts the latest research achievements and practical experience gained through the most challenging pipeline projects recently executed. The adopted limit state format allows for a large flexibility in design. It applies explicit design checks for physical limit states rather than implicit design check covering a number of failure modes. The safety philosophy adopted including the novel safety class concept will be discussed. The background for design criteria related to pressure containment are presented and the principles for assessing and accounting for the influence of system effects, material quality, hydro test and pressure safety systems are discussed. The implicit higher allowable utilisation given by the LRFD-format for the pressure containment is illustrated. Design performance, feedback from the industry and experience gained since the issue will be discussed.