Development of bridge management system for expressway bridges in Japan

Abstract

The Japan Highway Public Corporation (JH) that has been divided into three private expressway companies in October 2005 has been actively trying to reduce the maintenance costs for its express-highway networks. As the starting point of its series of efforts, JH has been trying to computerize all the processes of maintenance activities. JH proposed a total bridge management system (BMS) to support its decision-making process for well-planned maintenance by determining bridge condition, predicting future deterioration, and selecting optimal timing and method for repair and/or reinforcement. The original version of its BMS, called JH-BMS, was developed in 2003. Since then, some study results have been achieved to improve the quality of original JH-BMS. This paper discusses study results toward the development of JH-BMS, such as bridge soundness evaluation and deterioration prediction based on the inspection results, and optimum maintenance strategy to minimize life cycle cost. Future directions of research activities are also discussed. JHBMS is designed not only as a tool for proper budget allocation but also for supporting engineering decision-making process in the practical bridge maintenance field. JH-BMS is a decision-making support system on planning of bridge repair or reinforcement. The system uses a bridge maintenance database including the bridge specifications and inspection data in order to evaluate the soundness of bridge elements, predict deterioration, select optimal timing and method of repair or reinforcement and calculate the estimated costs. In JH-BMS, bridge conditions are evaluated by individual elements. Current condition of individual bridge elements is evaluated based on the inspection results, environmental condition and expected future traffic volume. And then, future deterioration of the elements is predicted at the time of inspection depending on the deterioration mechanism. The basic approach of JH-BMS is to calibrate the existing deterioration prediction equations (formulas) developed in Japan, based on the field inspection data. In these equations, specific mechanism of deterioration of each structure such as chloride attack or fatigue expected under severe environmental condition is taken into consideration. Historical inspection data will be used in JH-BMS to improve the accuracy of soundness evaluation and deterioration prediction of individual bridge elements. The results of accurate deterioration prediction enable the proposal of well-planned bridge maintenance strategies including preventive maintenances actions.