Reliability and Redundancy of Offshore Structures

The purpose of this study is to develop a general method for estimating the system reliability of offshore structures with the aid of the full distribution method and to introduce a probabilistic definition of structural redundancy. Structures are treated as systems of structural components. Failure of any number of these components results in a redistribution of the internal and/or external forces. The probability of structural failure is then evaluated by examining a limited number of significant sequences of member failures that produce collapse of the structure. The structure examined is an indeterminate deep off shore truss under fully developed sea conditions. Two different types of material behavior are considered to characterize the type of failure of the components: ductile and brittle behaviors. This reliability analysis and redundancy definition will form an important analytical basis for further investigation of offshore structural integrity.