Strengthening Glulam Beams with Steel and Composite Plates

Paper in proceeding, 2009

The stiffness requirements in the design of timber beams in serviceability limit state is a factor that often makes it necessary to increase the beam dimensions beyond what is required for strength. This causes increased material use and thus higher production costs. This study is an effort to investigate the viability of using Steel and CFRP (carbon fibre reinforced polymers) as reinforcement in new glulam beams. By gluing CFRP to the tension side of the beam it is possible to move the fracture from tensile rupture to the compression side of the beam which is beneficiary due to the more ductile behaviour of wood in compression. In the experimental part of the investigation, nine glulam beams strengthened with bonded steel and CFRP-laminates were tested to failure. The effect of various geometrical properties for the laminates was investigated, as well as strengthening with different amounts of laminates on the tension and compression side.