The social infrastructure, constructed in the period of rapid economic growth, is rapidly aging. It is very likely that social infrastructures using for many years will be damaged and destructed unexpectedly, which may result in serious damages to the life or assets of people. Even ending up in no troubles, the convenience of life may be lost.

To utilize the social infrastructure safely for many years, it is important to correctly measure and diagnose the type, location, and degree of the deterioration to predict the exact time of occurrence of the damages, and it is necessary to develop a technology that traces back to the cause of deterioration instead of conventional and empirical inspection and diagnosis technology.

The "Deterioration Diagnosis and Life Management Technology of Social Infrastructure" advocated in this strategic program means the measurement and diagnosis of the aged deterioration for the lifelines that support the life of people such as roads, bridges, railways, electricity, and water services, and the deterioration for the facilities that may intensely impact on the social activities and may give serious damages on people at the worst, in order to ensure the safety by detecting the symptom of the damage and destruction earlier than in the past by the evaluation of the life expectancy which is reflected on the maintenance, reinforcement and upgrade plan.

This technology is composed of following technologies: a technology relating to sensor and data processing of nondestructive measurement and diagnosis for the deterioration and damages of facilities; a technology for predicting the life expectancy according to the operating stress or external force such as earthquakes based on the deterioration phenomenon model, the damage marginal valuation model, or the combination of the models; a technology for monitoring the symptoms of damages and destruction in full-time basis; a technology for arranging sensors optimally; and a technology for data communication processing.

A part of elemental technologies including the deterioration model or the destruction limit evaluation model that determines the damage or destruction of facilities resulting in deterioration, has been independently developed. However, as a whole, it is necessary to develop and advance the elemental technologies, insufficient for highly credible life expectancy prediction or detection of damages and destruction, and to incorporate the data obtained in fields into the technologies to construct a system. Many of social infrastructures are maintained and managed by the state, local governments, IAAs and other public organizations, however, in many cases, the technical transactions of the maintenance and management are outsourced to private sectors. Especially, it may be difficult for private companies to independently promote the technology which is strong in its basic and commonness features and is including the basic research such as measurement principle and deterioration model, therefore, it may be reasonable for the government to take initiative from the viewpoint of taking full responsibility of the maintenance and management for social infrastructure.

By carrying out this proposal under the leadership of Japan, accidents can be avoided by detecting the symptom of damages and destruction earlier, and the aged social infrastructures can be appropriately fixed or replaced by diagnosing the life expectancy precisely, which will contribute to the improvement of safety and reduction of social economic load. In addition, the elemental technology for deterioration measurement and diagnosis as well as the modeling for deterioration mechanism may be advanced, which will enable the prediction of deterioration phenomenon at an environment difficult to measure directly.