Bridge health index considering deterioration mechanisms based on statistical analysis of visual inspection data

This paper presents the resutls of an evaluation of the bridge health index for 1325 bridges managed by the Gifu Prefectural authorities. The proposed bridge health index is statistically calculated using data from periodic inspections conducted by the authorities between 2001 and 2010. The database contains the results of five-step discrete data on many items set for decks, girders, expansions, shoes and accessories. The five-step grading is based on visual observation of the degree of deterioration for various members and components. However, due to the excessive amount of inspection items and components in bridges, the summarized grade obtained in this inspection is insufficient for making an effective repair and maintenance plan. Accordingly, indices that enable an overall evaluation of each bridge (or main components such as RC deck) are required. This study aims to express health indices for the RC decks of steel bridges and the PC girders of concrete bridges using an overall indices based on principal component analysis, which can clarify identify the health condition of the bridges with deterioration mechanism. Furthermore, the possibility of uniformly evaluation with RC decks and PC girders was considered.