| With the ever decreasing availability of prime lumber, research must be conducted to develop more efficient uses for our wood natural resource. This research program was conducted to develop composite glued laminated (glulam) beams using Fiber Reinforced Plastic (FRP) materials. A preliminary study, conducted by Dorey and Cheng (1996), examined the potential of Glass (GFRP) and Carbon (CFRP) fiber reinforcement for glued laminated (glulam) timber beams and concluded that, despite the superior mechanical properties exhibited by the CFRP, when project economics were considered, GFRP appeared to be the superior reinforcing material.; The main test program involved investigating how a number of different parameters, specifically fiber profile, fiber fraction, weathering effects and beam size, affects the overall strength and stiffness of a GFRP glulam timber specimen. Results indicate that all of the fiber reinforced specimens showed a significant increase in strength over the unreinforced samples. Maximum strength and true stiffness enhancements of 127% and 120%, respectively, were achieved for specimens with only tensile reinforcement at a fiber fraction of 7.06%. Maximum strength and true stiffness enhancements of 149% and 202%, respectively, were achieved for doubly reinforced specimens at a fiber fraction of 6.74%. The weathering tests showed that there was no significant effect on the phenolic resorcinol formaldehyde bond between the glass fiber and the adjacent wood fibers. Beam size effects were inconclusive from the test data because of the height to width ratio selected. A strain compatibility model was developed and provided a test to predicted ratio of 1.062. |
