Evidential reasoning approach for bridge condition assessment

Bridge condition assessment is usually conducted by bridge inspectors on the basis of visual inspections. This inevitably involves human being's subjective judgments and uncertainties. In order to model uncertainties associated with subjective assessments, this paper presents an evidential reasoning (ER) approach for bridge condition assessment. The ER approach has the following advantages over other approaches for bridge condition rating: (1) the relative importance of different bridge components and elements is incorporated into the model; (2) bridge condition ratings are treated as assessment grades rather than precise numerical values, which is more logical; (3) bridge element can be assessed to two adjacent assessment grades at the same time if it cannot be precisely assessed to only one assessment grade, each with a belief degree (probability, confidence) to show to what extent the element is assessed to the two different grades, respectively; (4) the overall assessment of a bridge is a distributed assessment, which provides a panoramic view about the bridge condition. A case study is provided to illustrate the implementation process of the ER approach for bridge condition assessment.