| Laminated timber bridge decks reinforced with fibre reinforced polymers (FRP) are a relatively new and promising alternative to traditional laminated timber decks and concrete slab decks, offering light weight and high strength, at low cost and reduced construction times. FRP reinforcement has also been shown to protect timber elements from environmental strains and reduce the variability in the strength of timber, allowing the bridge decks to remain in service for longer periods without deterioration or the need for regular maintenance.This report outlines the research conducted to analyze the behaviour of FRP-reinforced timber decks under live loading and develop appropriate simplified design methods. Specifically, simplified design methods presented in the Canadian Highway Bridge Design Code (CHBDC) for bridge deck design and longitudinal load distribution are examined and the principles used in their formation adapted to this application.Material properties are characterized from testing and analytical models and are used to develop models of transverse deck flexural strength, load distribution in the deck, and distribution of bending moments and shear forces to bridge girders. Non-linear moment-curvature models of the deck section are used to determine the ultimate strength of the deck section and appropriate reinforcement ratios. An orthotropic plate model is used to analyze deck behaviour and determine appropriate expressions for the load distribution parameter, Dt, used in CHBDC deck design. The semicontinuum method is used to model full bridge behaviour, and D-type analysis is applied to establish girder moment and shear distribution parameters for single and two lane bridges.Though several bridges using this technology have been built across Canada, design has relied on traditional methods which do not accurately represent the behaviour of these decks, and therefore do not take full advantage of the benefits of using FRP-reinforcement. |
