Glulam beams strengthened with pre-stressed basalt fibres

Timber has throughout history played an important role in all kinds of construction work where its properties are very sought after. Engineered timber products such as glulam have managed to increase these properties even more with stronger and stiffer material. In recent years new ways have emerged that enhance these properties even further by strengthening it with materials that have more tensile strength and higher modulus of elasticity. To study the effect of gluing basalt fibres on the tension zone of glulam beams an experiment was conducted in the structural laboratory (Sel) of Reykjavik University. 12 glulam beams 3,2 m long, 65 mm wide and 167 mm high in strength class GL30c were randomly divided into 3 groups with 4 beams in each group. For each group the beams were either reinforced with slack basalt fibres, pre-stressed basalt fibres or with no reinforcement for comparison. The reinforcement ratio of the basalt fibres was about 0,45% of the beams cross section for both slack and pre-stressed beams. The pre-stressing was done with cambering where the beam was cambered to the point where the stresses in the timber reached 90% of authorized stresses according to the standard EN 14080:2013. The beams were then tested in a four-point bending test. Results of the experiment showed a 37% increase in moment capacity for the slack reinforced beams and 64% for the beams reinforced with pre-stressed fibres. The modulus of elasticity also increased but not as much as the moment capacity or 11% for the slack reinforced beams and 19% for the pre-stressed beams. When the experimental results were compared with values estimated by calculations to predict the pre-stress in the fibres and the moment capacity, an apparent difference was found in the values where the calculations under estimated the moment capacity and overestimated the pre-stress. Keywords: Strengthened glulam, Basalt fibres, Pre-stressed glulam, Cambering

Author dc:creator

• Guðmundur Ingi Hinriksson 1981-

Contributors dc:contributor

• Háskólinn í Reykjavík

• Byggingarverkfræði
• Meistaraprófsritgerðir
• Timbur
• Burðarþol
• Tækni- og verkfræðideild
• Civil engineering
• Timber
• Strength of materials
• School of Science and Engineering

Language dc:language.iso

en

Handle dc:identifier.uri

http://hdl.handle.net/1946/25603

OAI identifier oai:identifier

oai:skemman.is:1946/25603