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Reference Details
Dagher H., Lindyberg R. 2003. "Development of AASHTO specifications for FRP-reinforced glulam beams", Transportation Research Board.

FRP-glulams are obtained by reinforcing the tension and/or compression sides of glued laminated (glulam) beams with Fiber-Reinforced Polymers (FRP). This paper describes a mechanics-based numerical model for FRP-glulam beams that is being used to develop AASHTO bridge design specifications. The paper compares the modelís 5th percentile Modulus of Rupture and bending stiffness predictions with those calculated from 250 laboratory beam test results. The model shows excellent agreement with the laboratory test results, particularly in its ability to predict 5th percentile values which form the basis for wood design properties. FRP Tension reinforcement was observed to significantly increase girder bending strength (by over 100%) and to a lesser extent bending stiffness (by 10%-20%). Reinforcement also reduces variability in mechanical properties which allows for higher design values. The model shows that the volume effect in FRP-glulam beams gradually disappears with increasing tension reinforcement ratios, and that the volume effect is eliminated at an E-glass tension reinforcement ratio of 2%. This result is particularly significant for long non-southern pine glulam girders where the volume effect may reduce bending strength by up to 30%. Tension reinforcement also increases ductility which provides for a safer failure mechanism. Ductility ratios near 3 have been calculated from beam laboratory test results. With the increased strength and elimination of the volume effect, the smaller, high-performance FRP-glulam bridge girders may present a viable alternative to conventional glulams.
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