Discussion on Social Discount Rate and Most Suitable Timing for Repair Work in Maintenance Planning of Infrastructure

Abstract

It is essential to keep functions of existing infrastructure over their required levels, which may contribute sustainable social and economic development in Japan. For this purpose, it is important to plan an appropriate maintenance strategy based on the preventive maintenance scenario rather that the collective maintenance one.
However, the significance of the social discount rate has not been made clear when estimating the life cycle cost for necessary interventions in the preventive maintenance scenario. There still remain controversial issues on either the discount rate should be taken into account or not.
This paper firstly examines the concepts of the social discount rate in various fields. Then, the differences were made clear when the social discount rate is taken into account or not. Finally, a calculation model was formulated to propose the most suitable timing for repair work when the social discount rate is taken into account.