ABSTRACT
Visual inspection of existing bridges is the main source of information to prioritize maintenance. This qualitative examination is thus a critical part of civil infrastructure management. In Switzerland, main inspections are typically made every five years on bridges. The bridge condition is scored from 1 (good condition) to 5 (alarming state) by inspectors. This global evaluation is taken as the worst score among bridge-element conditions that are individually assessed during the visual inspection. As these evaluations do not account for the importance of this element to global structural safety, the bridge condition is often inaccurately evaluated by bridge inspectors. This paper proposes a methodology to assess the bridge condition in which bridge-element evaluations are coupled with element-failure consequences on the structural safety following a risk analysis. In this risk-based methodology, the bridge condition score typically depends on the conditions of the most important structural elements such as main girders and piers. Visual-inspection reports have been collected on a road including 60 bridges in Switzerland, and bridge-condition assessments are compared between the conventional and the risk-based methods. Based on a new visual inspection made by the authors, results show that the risk-based methodology provides more accurate bridge-condition evaluations than conventional approaches. Inspection reports often concluded in over-pessimistic bridge-condition assessments, while the proposed methodology helps reduce subjectivity by providing a quantitative approach for bridge-condition evaluations.
