Structural Preservation of the Japanese Historical Timber Bridge: Kintaikyo Bridge

The Kintaikyo Bridge was originally constructed in 1673. The Kintaikyo Bridge has undergone repairs and renovations on countless occasions. The City of Iwakuni, home of the Kintaikyo Bridge, bears the responsibility of preserving the Bridge for present and future generations. Despite the Bridge's unique five-span arch structure, which is designed to enhance durability, the Bridge is vulnerable to natural disasters such as floods and earthquakes. As a way of long sustaining the Bridge, the City of Iwakuni decided to guarantee the succession of bridge construction technology, so as to ensure repeated rebuilding of the Bridge. This solution is unique in the history of bridges in the world. In this paper, the background of bridge construction, the bridge construction system and the structural characteristics of the Kintaikyo Bridge will be dealt with, in which each of the central three spans of the Bridge is proved to be a unique arch structure. And finally the structural preservation of the Bridge will be discussed.