Abstract
In East Japan, the bridge structures face severe environmental condition which induces composit deterioration of salt damage, frost damage and more. The estimation of deterioration rate and the analysis of predominant factors of deterioration would be effective for improving the efficiency of bridge maintenance. To evaluate the deterioration risk quantitatively, two types of survival analysis, Kaplan-Meier estimator and Cox regression analysis, are applied to the periodic inspection data of bridges in East Japan. KaplanMeier estimator is applied to the PC bridge girders' data. The difference of deterioration rate between deterioration mechanisms can be discriminated by the estimator, and degradation tendency can be determined. Cox regression analysis is applied to RC slabs' data to estimate the respective effect of structural and environmental condition on the deterioration. In this analysis, the predominant risk factors are quantitatively explained, and the validity of estimation is assessed by actual inspection records. Furthermore, by comparing the calcurated hazard rate of individual bridges, the actualized or potential risks are evaluated quantitatively. These results demonstrate the applicability of survival analysis to the inspection data, which can introduce the reasonable insight to bridge maintenance.
