Abstract
Recently, some bridges which were built for the rapid economic growth period become obsolete all once in Japan. The percentage of bridges beyond 50 years after construction is about 18% in 2013, it becomes approximately 43% in 10 years and becomes approximately 67% in 20 years. There has been a great discussion about appropriate method of the maintenance of bridges in a limited budget. The regular inspection is carried out once in 5 years to grasp and diagnose the state of each material of bridges. The repair priority of each bridge is determined and recorded depending on health of respective components and importance of the bridge.
However, the natural environments that each bridge is put are different, and it is expected that deterioration rate is different. So the priority decision of bridges have to be considered not only the soundness of bridges provided by a regular inspection and the importance of bridges but also natural environments.
In this study, we analyzed the relationships between soundness of bridges and the natural environments using regular inspection data of Ishikawa Prefecture. Some bridges in Ishikawa Prefecture has been placed under the harsh environment. For example, the harsh environment are spraying antifreeze in the winter season, flying salt from the sea in the route facing the Sea of Japan, the fatigue of bridge by weight and the shock of the traffic vehicle in the urban area with much traffic and so on.
