Sustainable Technology of the Japanese Historical Timber Footbridge －The Kintaikyo Bridge－

Summary The Kintaikyo Bridge having been designated a national cultural property, the City of Iwakuni, home of the Kintaikyo Bridge, bears the responsibility of preserving the Bridge for present and future generations. The Bridge’s unique fivespan arch structure is a treasure that was created from the wisdom, effort and ingenuity of our ancestors. As a way of long sustaining the Bridge, the City of Iwakuni decided to guarantee the succession of bridge building 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 are dealt with, in which each of the central three spans of the Bridge is proved to be a unique arch structure. And finally the sustainable technology of the Bridge is fully discussed.