Structural capacity deterioration is among the main causes of increasing failure probabilities of structural systems. The objective of this paper is to investigate probabilistic approaches based on the annual reliability index and annual risk of structural systems.

The article presents a review of the theory of reliability and its use for design code making procedures based on the probabilistic approach. Principles of structural safety in design code making are considered. This review article cites 135 references national and foreign authors.

The concept of optimal distribution of protective resources for structures in emergency situations, as technogenic, as well as earthquakes, tsunami, tornado’s, and other accidental actions is introduced. Minimax criterion is proposed. For an analysis of the type of «cost-efficiency» the target function is used.

The sources and the character of uncertainties in engineering modeling for reliability analysis are discussed. The paper comprises the Bayesian approach for the correct analysis (study) of the mechanical properties and influence of uncertainty on reliability index.