Influence of temperature on the bending capacity of timber beams strengthened with CFRP laminate
Journal Title: Annals of WULS, Forestry and Wood Technology; Zeszyty naukowe SGGW - Year 2016, Vol 94, Issue
Abstract
Influence of temperature on the bending capacity of timber beams strengthened with CFRP laminate. Nowadays external bonding of high strength fiber laminates is very popular method of enhancing the load capacities of existing structures. Sometimes those strengthenings are subjected to direct sun exposition. Paper shows the dangers appearing due to the uncontrolled growth of temperature caused by the solar radiation. Possible development of temperature was investigated by the exposition of timber samples during the summer months in the southern Poland. The maximum noted temperature in the adhesive layer exceeded 70°C and was almost 10°C higher than measured together on concrete samples. This phenomena is caused by generally lower heat capacity and heat transfer ability of timber. The second part of the experiment consisted of bending tests of timber beams heated from the strengthened side with the use of linear infra-red radiators. When the temperature measured in the adhesive layer reached the 70°C beams were loaded to the moment of failure. Despite fears, such a temperature did not result in loss of adhesion and delamination of overlays. Only a slight decrease of stiffness and consequently the strengthening effectiveness was observed. It means that CFRP strengthening of timber elements, which could be subjected to direct sun exposition should be protected by additional layer of thermal insulation able to reflect the infra-red radiation
Authors and Affiliations
Rafał Krzywoń, Marcin Górski, Szymon Dawczyński
Keywords
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