Structural reliability – fuzzy sets theory approach

In the paper two kinds of uncertainty: randomness and imprecision are proposed to be considered in a structure description. Imprecise experts' opinions can be described using fuzzy numbers. As a result, the reliability analysis of a structure can be based on the limit state function with fuzzy parameters. As a consequence, the structural failure or survival can be treated as fuzzy events. The probabilities of these fuzzy events can be the upper and the lower estimations of the structural reliability. They can be achieved using well-known reliability methods (e.g. Hasofer-Lind index and Monte Carlo simulations). They can be used as a base for the calibration of partial safety factors in design codes.