抄録
In order to maintain the soundness of the steel bridges in Japan rationally on the limited budget, the method which can do the effective preventive maintenance based on the degradation characteristic of the steel bridges and extension of life-span needs to be performed. This research analyzes periodic inspection results of the steel bridges on national roads of almost all of Japan from a viewpoint of an elucidation of the degradation characteristic. The transition probability of soundness which presumed time-homogenious as a premise differs greatly for every kind and environmental condition of damage. Moreover, the factor which has influence dominant in degradation by a multivariate analysis was not able to be specified.
