Reinforcement of Bolted Timber Joints Using GFRP Sheets in Poplar and Pine Woods

Failure in timber structures occurs mainly in crucial points such as joints areas.Therefore, the idea of using composite sheets in timber joints has been introducedas a method in order to increase the strength and ductility behaviour oftimber joints. This research aims to study the behaviour of bolted joints in poplar andpine woods, which are reinforced by two types of GFRP sheets. A single shear boltedjoint consisted of 3 timber members whose length and width were 30 cm in lengthand 5 cm in width. The thickness of each member was 4 cm for internal part and 2 cmfor external part. The employed steel bolt was 10 cm in length and 1 cm in diameter.In this respect, one layer of GFRP sheet was used to be bonded to timber membersby using epoxy resin and left between the clamps for 24 hours. They were then keptat room temperature for three weeks. Also the effect of adding a wood veneer on thereinforced joints was investigated. The tensile strength of the reinforced and controlsamples (un-reinforced joints) was measured according to ASTM D5652-92 standard.The results show that the reinforced samples have higher tensile strength comparedto that of reinforced joints, although it is not statistically significant. Also, two typesof sheets influence the joint behaviour as the reinforced joints display more ductilitybehaviour.