Calculation of Corrosion Limit State Safety Factor by Application of Fuzzy Set Theory

Besides live loads, reinforced concrete structures are affected by many other influences that may reduce their safety. Corrosion of reinforced concrete structures may be observed in two time periods characterized by different intensities of the corrosion process development. They are an initiation period of the corrosion process and the propagation period of the corrosion process. Consequences of the reinforcement corrosion in concrete are the reduction of the steel bars' area and cracking of the concrete cover. The reduction of the reinforcement cross-section’ s bearing due to corrosion over a sufficiently long time period may result in bearing failure of the dimensioned cross-section. It is impossible to give a quantitative expression of all the factors’ influences, which cause the reinforcement corrosion resulting in reduction of the bearing area. Their influences are taken into account in the dimensioning procedure through the corrosion limit state safety coefficient. The description of the influence of some factors is qualitative, and the calculation according to the fuzzy set theory is taken as the most appropriate procedure for the safety coefficient definition.