Feasibility Investigation into Strengthening of Timber Bridge Stringers

摘要

The majority of timber bridges in the United States are nearing the end of their service life. They exhibit several types of damage, which occurs in their structural elements such as timber stringers. The most commonly encountered damage type in timber stringers in bridge structures is horizontal splits. Researchers investigated the feasibility of repairing timber stringers that showed signs of horizontal splitting along the length of the member. Timber stringer damage types were reviewed with particular attention to horizontal splits along the span, and the factors contributing to these failure types were studied. Typical timber stringers recently taken from service were examined to understand the effects of horizontal split damage and its impact on the effectiveness of the repair methods. Several methods for repairing horizontal splits along the span of timber stringers were employed, including fiber reinforced polymer plates attached to the vertical sides of the stringers with lag screws. Thirteen stringers were repaired with approximately 44% increase of the unstrengthened post failure load capacity. It was proven that the methods examined in this study may be feasible to repair timber stringers with horizontal splits.