A country has been devoting a lot of attention in order to prepare the aging facilities. we were examined the status of hydrological facilities and reviewed the detailed guidelines for the safety assessment procedure. This study were derived the problems of safety assessment procedure by comparing detailed guidelines and field applications. Also, we proposed improvement plan of the assessment procedure.

The Goal of research is that decision-making in bridge and tunnel maintenance were estimated by prediction models of condition and value engineering. We developed the software that can be calculated asset values and it’s condition depending on budget scenario by the bridge and tunnel prediction model. It can be determined an optimal budget of facilities and it’s values using prediction model of cost and condition.

The in-depth inspection and maintenance process is based on the ‘Special Act on the Safety Control of Public Structures’ and accompanied specific guide. They prescribe the evaluation standard for physical condition and safety on structures. Recently we are faced with the threat coming from the aging of structures and external condition such as climate change. In this study, sustainable and long-term maintenance strategy is derived.

「Special Act for the Safety Control of Public Structures」is for the periodical inspection and maintenance on the main structures. It is based on the reactive measures for the found faults and the maintenance budget is allotted with a ceiling. Therefore decision makers cannot establish long-term strategies and connot consider the serviceability from a user's point of view. The infrastructure maintenance system has to be renewed considering for the efficiency in the face to the rapid increase of the rate of deteriorated facilities.