Fuzzy reliability in hydraulics

A fuzzy reliability model is developed for a flood levee where both load and resistance are assumed to be fuzzy. A new measure of reliability index is proposed within the framework of fuzzy set theory to assess the reliability of such a hydraulic structure. The methodology is illustrated with a case study on an existing levee system of Sebes-Koros River in Hungary. The load is taken as the fuzzy wind wave action above the 100 year flood level; the resistance of the levee to wind waves is also considered to be fuzzy. A parametric analysis on the widths of the fuzzy set membership functions of both load and resistance is carried out. The results indicate that the proposed index may be a viable measure of reliability in such problems