Target Design Levels for Maritime Structures

Abstract

The main objective of a project is to verify the requirements and target levels for values of reliability, functionality, and operationality during the useful life of the structure. Such requirements should be provided by external studies carried out by the promoter. In their absence, the engineer has to specify requirements using his or her own criteria. This paper describes a procedure that defines the target levels for maritime structures in terms of their general and operational intrinsic natures. These natures are used to evaluate the importance of the structure as a function of the economic, social, and environmental impact produced in case of serious damage or a total loss of functionality and stoppage, respectively. This procedure gives recommendations for values of a structure’s minimum useful life, joint probability of failure against the principal failure modes, adscribed to ultimate and serviceability limit states, minimum operationality, average number of admissible technical breakdowns, and maximum allowed duration of a stoppage mode.