Generalized Second Moment Reliability Index

ABSTRACT A crucial property of any measure of structural reliability should be comparativeness. With this point in mind this paper discusses some well-known versions of so-called reliability indices. Such reliability indices, defined by use of second moment information, have been used for the last decade, specifically within safety code committee work. This paper defines a generalized second moment reliability index that satisfies some few fundamental canonical rules and principles of simplicity. The reliability index is specifically defined to be used when no high quality information is available to the engineer other than the limit state surface and a second moment representation for the set of basic variables of the structural problem. In a parallel paper the author demonstrates the practical operability of this reliability index even for multimode failure systems.