Reliability-Based Screening of Offshore Platforms

Abstract

This paper describes development of a reliability-based screening procedure for platform assessments and requalifications. The objective of this procedure is to identify the critical structures and structure components that need to undergo a detailed assessment so that limited resources can be efficiently used. The reliability-based screening procedure helps identify potential failure modes and weak links in the structure, and provides information on the effects of load reduction and strengthening measures on the reliability of the platform. The reliability analysis screening procedure is based on a first-order second-moment (FOSM) formulation. A study is summarized of the implications of the simplified FOSM method. In the case of an eight-leg drilling and production platform located in the Gulf of Mexico, the results from FOSM reliability analysis are compared with those from first and second-order reliability methods (FORM and SORM). There is excellent agreement between the FOSM and FORM/SORM results.