A fuzzy expert system for deterioration modeling of buried metallic pipes

This paper presents the framework of a proposed expert system that is used to predict the deterioration rate of buried metallic pipes, based on surrounding soil properties. The knowledge base of the expert system is developed using two sources of information available for evaluating the deterioration of pipes: expert knowledge and field data. The novelty of the proposed approach lies in the modeling process and the framework of the expert system, complying with the nature of the information available. The knowledge base is composed of a subjective and an objective model. The former is based upon fuzzy IF-THEN rules representing the expert knowledge obtained from published work and an expert survey. It determines the soil corrosivity potential (CoP). The objective model is a single-input-single-output (SISO) model that relates the deterioration rate (DR) to CoP. The objective model may be developed using either fuzzy modeling or a regression analysis of field data. The result of the latter is based on a set of available field data, used in a previous study, is presented.