Main infrastructures in Korea are maintained according to the result from periodical in-depth inspection. The process is based on the ‘Special Act on the Safety Control of Public Structures’ and accompanied specific guide. The Act has mainly focused on the physical condition and safety of structures up to now. Recently we are faced with the threats coming from aging of structures and climate change. These interior/exterior changes are strong challenges to maintain expected performance of structures. What is more, convenience for people and functionality are came to the fore as important indices. In these circumstances, the government of the Republic of Korea is preparing for a paradigm shift to performance-based maintenance system which can evaluate integral condition of structures with regard to the various performances. In this study, performance indices, detailed inspection items and following inspection techniques are defined. The grade assigning method using the results from inspection and integral evaluation procedure are suggested. This can be used for establishing a improved and long-term maintenance strategy toward an appropriate goal considering various performance characteristics.

Construction projects of SOC(Social Overhead Capital) have been rapidly increased since 1970s in Korea. So, it is expected that the infrastructures which have been used for more than 30 years will be increased in a few years. The maintenance of infrastructures is essential because the deterioration of infrastructures can greatly influence the national economy and people by its failure. The existing evaluation method of tunnels in Korea is mainly focused on the structural safety such as appearance defects or safety factors. So it has many limitaions which do not consider the tunnels’ various performances, e.g. durability, serviceability and so on. Thus, the new concept of evaluation method is needed to deal with the structure aging issues and to keep the tunnels performances continuously. In this study, the new concept of evaluation method for existing tunnels will be presented. The performance requirements are derived from Delphi-survey which is a structured communication technique. And the weight factors of evaluation indices are derived from AHP(Anlaysis Hierarchy Process) analysis. Finally the total performance evaluation was conduted by field application of target tunnels in Korea to verify the proposed method.