A. GENERAL REMARKS During the last century, probabilistic methods for design and analysis of engineering systems have assumed a prominent place as an engineering tool. No longer do engineers naively believe that all problems can be analyzed with deterministic methods, but rather, it has been recognized that, due to unc- tainties in the model and the excitation, it may only be possible to describe the state of a system in terms of some random measure. Thus, with the need to address safety and design issues adequately and simultaneously to minimize the cost of a system, much attention has been given to the development of probabilistic criteria which can be applied in a systematic manner [l]t. These techniques allow for uncertainties in the parameters of the model as well as for uncertainties in both the static and dynamic loadings to be considered and therefore give a better measure of the reliability of a system. Widespread application of probabilistic methods can be found in disciplines ranging from civil, mechanical and electrical engineering to biology, economics and political science.