Bond behaviour of CFRP-to-timber interfaces

Abstract

The use of externally-bonded Carbon Fibre Reinforced Polymer (CFRP) sheet is a promising and effective method for increasing the shear and flexural strength of existing timber members. This study examines the bond behaviour of CFRP sheet adhesively bonded to a Douglas Fir timber substrate using a single-shear pull-off test. Eleven specimens were tested to analyse the failure mechanism, FRP strain and FRP-timber interfacial bond stress distributions. The influence of parameters including bond length and width are also discussed. The concept of effective bond length was demonstrated to be applicable for CFRP-to-timber bonded systems, which was found to be approximately 60 mm and 40 mm for the 0.167 mm and 0.111 mm thick CFRP sheets used in this study.