A SYSTEMS RELIABILITY CASE STUDY OF AN EIGHT-LEG JACKET PLATFORM

This report describes a systems reliability analysis of an idealized eight-leg, steel-frame offshore jacket platform located in 140-ft of water, and designed for a 100-year return period wave. The reliability of the steel-frame structural system (excluding piling) under gravity and extreme wave loads was estimated using a structural systems reliability analysis procedure developed at Stanford University /1/. Wave loads and member resistances were treated as random variables, and reliability calculations were performed using first-order reliability methods. Reliability analyses were conducted to study the effect of using X-bracing versus K-bracing in the principal load-carrying bents, the effect of wave load variability, the decrease in reliability under damaged conditions {simulated by removing selected frame members), and the adequacy of horizontal bracing to transfer loads among the frame bents.