Improved Interval Evidence Theory–Based Fuzzy AHP Approach for Comprehensive Condition Assessment of Long-Span PSC Continuous Box-Girder Bridges

A comprehensive condition assessment of long-span prestressed concrete (PSC) continuous box-girder bridges in service is the foundation of bridge maintenance and management. In this paper, first, the original interval evidence theory is improved through the conflict test of original evidence and the correction of conflict evidence based on credibility. Second, a new comprehensive condition assessment method considering the interval uncertainty of measured data and the impact of measured conflict data is proposed for long-span PSC continuous box-girder bridges through the natural integration of the improved interval evidence theory (IIET) and the fuzzy analytic hierarchy process (AHP). Third, to illustrate the implementation process of the proposed method, a three-span PSC continuous box-girder bridge is assessed considering the effect of spatial variability of materials and structural dimensions. The advantages of the proposed method over the existing AHP assessment method and the traditional combination method are verified by comparing the condition assessment results with the actual status of components or the whole bridge.