Effects of GFRP on bending strength of glulam made of poplar (Populus deltoids) and beech (Fagusorientalis)

• Fracture place was changed from shear side to compression side by increasing of GFRP layers in glulam timbers.
• GFRP materials improve mechanical properties of timbers.
• Produced the highest ultimate strength and stiffness in bending test.

The aim of this study is to investigate the bending strength of the specially reinforced glued laminated timbers (Glulams) with Glass fiber-reinforced plastic (GFRP). Glulam was produced using 5 layers of beech (Fagusorientalis) and poplar (Populus deltoids), which are widely used in Iran wood industries, Standard ANSI/ATIC/A190.1 was used for producing. Reinforcing process by GFRP was done using 4 methods including: using 1 layer and 2 layers of GFRP under the glulam layers (U1, U2) and 2 layers and 4 layers of GFRP between the glulam layers (B2, B4). Because of bending strength importance, this strength was investigated according to standard ASTM D 3737-03. The results showed that the highest strength and the lower strength in control samples made using any wood were obtained using epoxy glue and solid wood respectively. Also in reinforced glulam samples the highest strength was obtained using 4 layers of GFRP (B4). However samples made by beech wood have higher strength than samples made by poplar wood. Also the 3 point bending test results showed that fracture place was changed from shear side to compression side by increasing of GFRP layers.