Durability of timber bridges is improved by using concrete decks, because it substitutes a roof. In this case, dead load is increased but this disadvantageous point is canceled by making the timber-concrete composite girder. In Japan, Design Criteria for this type of timber bridges have been developed in 2002 at Nagano Prefecture. And this bridge had been constructed for the first in 2003.
In this paper, the improvement method for this type of timber bridge is suggested, that is to product a composition precast girder that has T-beam cross section with the web made of timber and the upper flange made of concrete. And the advantage is discussed from the viewpoints of cost reduction and labor saving.
