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Li, Yanbo

University of British Columbia

Development and application of bamboo in structural building in North America requires a reliable quality control method for bamboo raw materials and a suitable product which mechanical properties are predictable, controllable, and satisfies the local market demand while meeting the sustainability and supply chain concerns. The first part of this thesis investigated the feasibility of using stress wave based non-destructive evaluation commonly used to grade wood veneer for predicting the flexural modulus of elasticity (MOE) of flattened Moso bamboo. The goodness of fit between MOE and acoustic wave velocity (V) was low in bamboo compared with Douglas fir wood veneers because of low grain angle deviation in bamboo. Bamboo veneers showed lower V than Douglas-fir, likely linked to a combined effect of short cells with higher average microfibril angle. Segmenting by density can effectively group flattened bamboo veneers into different MOE grades (R² = 0.52) but combining density and wave velocity to compute dynamic modulus of elasticity gives more accurate prediction of apparent MOE (R² = 0.86). Part 1 suggested applicable quality control methods for non-destructively grading bamboo veneers. Part 2 of this thesis focused on the development of a bamboo-wood hybrid composite for structural applications. The effect of longitudinal cracks in bamboo esterilla was investigated as a pre-trail experiment. Results showed that the cracks did not significantly affect the MOR/MOE, bonding strength, and wood failure rate of bamboo esterilla when fabricated into a cross-laminated plywood. Three bamboos (Moso, Guadua, Vivax) were used to surface-reinforce oriented strand lumber (OSL) and a numerical model was developed to predict the effect of bamboo reinforcement on edgewise and flatwise stiffness. OSL surfaced with > 6.5mm thick Guadua and Vivax layers could meet the 1.75E target for edgewise MOE, and were comparable to common engineered wood products. The model mostly predicted the change in stiffness except for Guadua, likely because a different source of this bamboo was tested for baseline MOE input. Part 2 validated the potential of bamboo veneer and esterilla as a reinforcement material for structural composite lumber in timber building construction.

Text

2025-03-31

Attribution-NonCommercial-NoDerivatives 4.0 International

http://hdl.handle.net/2429/85588

Forestry

University of British Columbia

UBCV

http://creativecommons.org/licenses/by-nc-nd/4.0/