ReLAM: Nonlinear Probabilistic Model for the Analysis of Reinforced Glulam Beams in Bending

AbstractThe University of Maine, in conjunction with Willamette Industries, Georgia-Pacific, Strongwell, and APA—the Engineered Wood Association, tested 90 fiber-reinforced polymer (FRP)-reinforced glue-laminated wood (glulam) beams. This study showed that a FRP reinforcement ratio of 3% in tension can increase glulam-allowable bending stress (Fb) by more than 100%. Furthermore, this physical testing was used to verify a nonlinear probabilistic computer model for reinforced glulam, called the reinforced laminated (ReLAM) model. ReLAM uses moment-curvature (M-Φ) analysis and Monte Carlo simulation to predict the strength and stiffness of a population of reinforced glulams, requiring as input distributions of the lamstock long-span flatwise-bending modulus of elasticity (E), ultimate tensile stress, and ultimate compressive stress. ReLAM output lists the reinforced glulam modulus of elasticity (MOE) and Fb in terms of the gross cross-sectional dimensions, providing beam properties in the same fashion as the current tabulated properties for unreinforced glulams. ReLAM accurately predicted the Fb and MOE for the 90 reinforced glulams tested, demonstrating that it is a valuable tool for the analysis of reinforced glulams with various layups, reinforcing materials, and reinforcing levels.