Experimental testing of FRP plate reinforced glulam

In recent times, the use of pultruded fibre-reinforced polymers (FRPs) is becoming increasingly common in the construction industry. Designers have developed an improved understanding of the benefits that these materials offer in the stiffening and strengthening of steel and concrete structural members. However, limited research has been undertaken with regard to strengthening of timber members. This study examines the flexural reinforcement of low grade glulaminated spruce with a commercially attractive FRP plate incorporating glass fibres. The experimental test programme involved the testing of unreinforced beams, beams reinforced with FRP plates, unreinforced beams incorporating a sacrificial lamination and beams reinforced with FRP plates which included a sacrificial lamination below the reinforcement. The unreinforced beams in general displayed linear elastic behaviour and exhibited brittle tensile-flexural failures in comparison to the pseudo-ductile behaviour of the reinforced beams. The beams, which included both the reinforcement and sacrificial lamination, initially fractured in the sacrificial lamination after which significant ductility was exhibited. The load carrying capacity exceeded the initial fracture load in a number of the beams. The reinforced beams demonstrated modest enhancements in the stiffness of the section in comparison to the unreinforced beams. Furthermore, the reinforced beams showed satisfactory improvements in the ultimate moment carrying capacity in comparison to the unreinforced beams. No bond failures were observed throughout the experimental test programme.