The Effect of Transverse Stiffener Beams on Shear Transfer

There are many wooden bridges in the United States. Their decks are often built of timber beams nailed together and covered with asphalt. The asphalt plays a mechanical role, and it provides environmental protection for the wood deck. The asphalt layer deteriorates and requires replacement. That leads to a faster deterioration of the deck, increased maintenance, and shorter bridge life. The flexibility of the deck is a probable cause of the fast deterioration of the asphalt. Low temperatures lead to deformations of the deck and may lead to cracks, which are propagated by mechanical and environmental effects. This project investigates stiffening the bridge deck by connecting a beam perpendicularly to the deck planks with metal bolts to reduce deformations of the deck. The additional beam is called a Transverse Stiffener Beam (or TSB). It can be incorporated as a part of new bridges or be attached to existing bridges. The investigations show the TSB significantly reduces deformations of the deck in most cases. The study indicates the positive effects of the TSB's should be expected in other applications. The magnitude of the effects can be analyzed with the computer program developed during this project.