Stress-Laminated Timber Decks Using Glass FRP Tendons

摘要

In stress-laminated timber bridges, longitudinal wood laminations are post-tensioned transverse to traffic. The prestress force causes friction to develop between the wood laminations, enhancing the load sharing capacity of the system and causing the behavior of the individual laminations to approach that of a continuous orthotropic plate. While stress-laminated timber bridges can be cost-effective and relatively easy to assemble, one of their biggest drawbacks is the need to periodically re-tension them in sevice due to creep in the wood. This paper describes the results of an experimental program in which Glass Fiber Reinforced Plastic (GFRP) tendons, rather than the commonly emploed steel threaded bars, were used to post-tension a laminated wood deck. It is shown that properly designed GFRP tendons can significantly reduce prestress losses. Initial results are encouraging and it may be possible to significantly reduce or even avoid re-stressing in sevice.