Bridge structural safety assessment: a novel solution to uncertainty in the inspection practice

Numerous bridges worldwide have surpassed their design serviceability life and often exhibit potentially severe defects. To ensure their ability to carry on with their designed duties, a series of visual inspections are regularly carried out. Their output usually translates in the direct and unsupported assignment of a Defect Grade on the grounds of the inspectors’ experience and technical training. In light of such, said grade is affected by a non-neglectable amount of uncertainty which can lead to a wrong prioritization of maintenance operations and to the exposure of the infrastructure users to unnecessary risks. In the present article, a holistic analysis of the uncertainty in the bridge condition assessment inspection process was performed. The authors then attempt to decrease the uncertainty connected to the inspector’s subjective way of conveying an engineering constructs and communicating a verdict, a problem of semantic nature. To do so, a novel approach to the inspection practice is proposed on the grounds of a semantics-based defect evaluation. This one encompasses: (1) clear inspective objectives, (2) unambiguous definitions of the inspective lexemes, (3) a set of combination rules of the key inspective aspects and (4) a validation process to ascertain the correctness of a defect grade.