Applicability of Fuzzy-Based Visual Inspection Approach for Condition Assessment of Bridges in Developing Countries: A State-of-the-Art Review

Visual inspection method is a widely used technique for periodically assessing the condition of existing bridges. The visual inspection method is simple, easy to use and requires minimum investment. As a result, it is particularly suitable for developing countries where paucity of fund and availability of advanced equipments for condition assessment of bridges are limiting factors. However, the effectiveness and reliability of the assessment depend largely on factors such as the technical competence of the inspector, his/her experience, perception, judgment, etc. Such subjectivities, inherent in visual inspection method, may however be addressed by fuzzy approach. This technique has the capability to analyze a complex system, inherent with uncertainties, using approximate reasoning which is neither exact nor inexact. Therefore, fuzzy logic-based visual inspection approach couples the simplicity and economy of visual inspection method and mathematical rigor of fuzzy logic to minimize the uncertainty and unreliability of visual inspection data. As a result, it has the potential to be used as an effective tool for condition assessment and rating of bridges in developing countries. Hence, in this paper an effort is made to review the existing literature on this technique and its components under a few broad categories and discuss the advantages as well as limitations of each of them. Finally, knowledge gaps and challenges are discussed to motivate future research in this field for practical implementation in developing countries. © 2020, The Institution of Engineers (India).