How Classification will deal with the shifting from the traditional 20y design life to 40 or more

摘要

In the last years there has been a growing demand to push the traditional 20y design life for offshore floating production units to 40 or more. Although this demand is not surprising in civil engineering and for some of the existing gravity-based structures, it may lead to significant changes on the review of Classification Societies of their Rules for Steel Offshore Units. This paper will concentrate on the different ways that are being looked at to ensure a sound design and construction for units expected to last that long without any drydocking. From the practical application of ageing theories (coating, corrosion, fatigue, creep,..) to particular construction procedures and surveys (extend of full penetration, material selection, definition detail..), passing through lasting conscious designs, this paper will present the current philosophies and the lines of development that will provide the future rules. It will also give some insight to the typical examples of degradations that may limit the expected uninterrupted service life and the means available to detect and correct them in time. The authors hope that the paper will help the different players, designers, operators and contractors not only with the new units that are being discussed, but also on those already operating for ensuring a lasting, and why not, extended safe service life.