Investigating the flexural behaviour of reinforced laminated veneer lumber beam with near-surface mounted CFRP

This study investigates the effect of carbon fiber-reinforced polymer (CFRP) plate reinforcement on the flexural performance of laminated veneer lumber (LVL) beams using the near-surface mounted (NSM) technique. A total of six specimens were tested in four-point bending, including two control beams and four beams with CFRP plate reinforcement in the tensile zone. The variations of the CFRP plates considered included differences in depth plates. All test beams were compared in terms of bending strength, initial stiffness, midspan vertical displacement, and failure load. Experimental results indicate that the bending strength of the beams increased by approximately 37 % for a 20 mm depth of CFRP and 66 % for a 40 mm depth. In addition, the flexural stiffness of the strengthened beams improved by 21 % for the 20 mm depth and 37 % for the 40 mm depth. These results suggest that the NSM technique with CFRP reinforcement in tensile areas significantly enhances the structural performance of LVL beams, with depth being a critical factor in improving both strength and stiffness. Considering the contribution of CFRP plates, a theoretical model is developed to predict the ultimate moment capacity and bending stiffness of CFRP-reinforced LVL beams. It was shown that the predicted results closely aligned with the experimental ones.