Behavior of glulam beams strengthened with BFRP bars

Currently, FRP fiber composites are increasingly used in construction. They can be used in the form of: tapes, mats and bars. Composite rods are already widely used in reinforced concrete structures as replacements for steel rods. They are also used as elements for repairing various types of structures: reinforced concrete, timber, steel and masonry. It is much less popular to use composite rods as reinforcement elements for laminated timber beams at the production stage. The paper presents the results of experimental and numerical analysis of glued laminated timber beams, reinforced with BFRP basalt-epoxy rods to determine the effect of the distribution of composite reinforcement on the load-bearing capacity of reinforced joists. The tested elements were reinforced with bars of various diameters, arranged differently at the cross-section. The beams were made of GL24h wood, while basalt-epoxy bars with a diameter of 7 and 9 mm were used to strengthen the beams. During the experimental investigations, the deflection of beams, the value of the destructive force and the form of destruction, were investigated. Computer calculations based on the Finite Element Method (FEA) were also obtained, achieving good consistency of displacement results. In numerical studies, wood and composite rods have been modeled as an orthotropic material. The numerical analysis was carried out in the elastic range. In experimental studies, significant differences in the values of deflections and destructive forces in the scope of one research series were observed, which may be due to the inaccuracy of execution. Values of destructive forces in experimental studies were not directly related to the value of reinforcement percentage of different series of beams. (paper)