Experimental investigation of end-notched glulam beams reinforced with GFRP bars

Abstract

End-notched timber beams can have a significant decrease in load-carrying capacity as a consequence of stress concentration due to height reduction at the supports. To prevent crack opening and its propagation at the notches, these beams are usually reinforced. In this paper, extensive experimental research on end-notched glulam beams reinforcement with glass fibre reinforced polymer - GFRP bars is presented. Bending tests on unreinforced and reinforced end-notched glulam beams were carried out until the point of failure. Behaviour of tested beams is described through load–deflection diagrams, failure modes and ultimate loads. In addition, different reinforcement schemes of notches were analysed in order to determine an optimal configuration under the aspect of load-carrying capacity improvement in relation to the unreinforced beams. The effectiveness of GFRP bars as a reinforcement of end-notched glulam beams was evident from significantly increased ultimate load and deformability. The design procedures for unreinforced end-notched beams according to Eurocode 5 and reinforced end-notched beams according to German national annex of Eurocode 5 were analysed through comparison with the experimental results. Recommendations for the design of GFRP reinforcement are given.