Abstract
Serviceability assessment of existing bridges relies heavily on subjective judgements based on heuristics to be made by the experts. So, it is important to consider how to extract and express heuristics that has a certain level of intrinsic fuzziness due to subjectivity. In this paper, an empirical knowledge acquisition method is proposed by relating the knowledge, acquired from questionnaires, with a basic probability based on Dempster & Shafer theory, and quantifying the subjective uncertainty included in the knowledge using the concept of Yager's measure and Dempster & Shafer theory. Furthermore the proposed method has been applied to a questionnaire conducted to evaluate the serviceability of an existing bridge. And the validity of the method is verified through the comparison between the subjective rating results acquired from the application of the method and the objective rating results obtained from various field tests conducted to a same bridge.
