PURPOSES : With the recent enactment of the 「Framework Act on Sustainable Infrastructure Management」 in Korea, the establishment of mid- to long-term management plans for social infrastructure and the feasibility evaluation of maintenance projects have become mandatory. To this end, the life cycle cost analysis is essential. However, owing to the absence of a deterioration model, trials and errors are in progress. METHODS : In this study, a deterioration model was established for bridges, which are the representative social infrastructures of roads, particularly for expansion joints that can cause enormous damage to not only the superstructure but also the substructure. The deterioration model was classified into rubber and steel, based on the material of the expansion joint. The analysis used the inspection and climate data conducted in Korea over the last 12 years. The Bayesian Markov Hazard model was applied as the analysis technique. RESULTS : The average life expectancy by type of expansion joint was analyzed to be 8.9 and 6.6 years for rubber and steel, respectively. For probabilistic life cycle cost analysis, the probability distribution of the life expectancy, validity range by confidence level, and Markov transition probability matrix were presented. CONCLUSIONS : In this study, the basis for deterministic and probabilistic life cycle cost analysis of expansion joints was laid. In future studies, it will be necessary to establish a standardized deterioration model for all types of infrastructure, including all bridge elements.

As the service period of bridges becomes increased the maintenance and management of existing bridges become also more important. Korea Expressway Corporation has collected data on the maintenance for a long period but those obtained data has rarely been thoroughly analyzed for the maintenance purposes. This study investigated the service life of extension joint of bridge among various bridge members and this attempt should be very meaningful as using the data obtained from the field. The service life of the extension joints can be used for the development of maintenance strategy in the future.