Creep behavior of FRP-Reinforced wood members

In this study, the writers aim to provide a basic understanding of the creep behavior of wood members reinforced with fiber-reinforced plastic (FRP) materials epoxy-bonded to the tension faces. An analytical method is presented first for the deformation of cross sections based on a Burger model combined with a mechanosorptive element for wood, Findley's model for composite materials, and a stress-relaxation procedure to yield the cross-section stresses and strains as a function of time, for both constant and variable temperature and humidity conditions. Parametric studies assessing the effect of the type and area fraction of composite material on the creep response of FRP-reinforced wood members are also presented, for both constant and variable environment. Finally, the analytical model is employed to predict the time-dependent deflections of wood beams reinforced with carbon fiber-reinforced plastic (CFRP) laminates of different thicknesses, and the results of a short experimental program involving FRP-reinforced wood beams under constant environment conditions are also described. The (limited) results are in good agreement with the analytical model.