Application of fuzzy sets for estimating service life of reinforced concrete structural members in corrosive environments

In this work, an effort is made to use the ability of fuzzy sets in handling uncertainties for evolving a general methodology for durability-based service life design of reinforced concrete structural members. In the proposed methodology, the variables defining the quality of construction, workmanship and exposure conditions are treated as fuzzy variables. The exposure condition of the member is represented by a quantified environmental aggressiveness factor (EAF). Based on the value of EAF and the specifications given in any code of practice, the grade of concrete, water–cement ratio and the required cover thickness can be determined. After designing the member using the existing standard design procedures, service life of the member can be estimated using the proposed methodology. In the present work, service life is estimated based on the degradation in resistance of the member due to loss of area of reinforcement caused by chloride-induced corrosion—a major concern in coastal environments. An example problem is provided to illustrate the efficacy of the proposed methodology.