Analysis of adhesive joints used to bond FRP laminates to steel members – A numerical and experimental study

The strengthening of existing structures using bonded fiber reinforced polymer laminates has attracted agreat deal of attention in recent years. However, when compared with concrete structures, the applicationof this method for strengthening structural steel members is somewhat limited. This is mainly due tothe lack of an established design code for treating FRP-strengthened members. Issues such as the complexityof failure modes and the lack of knowledge of the force-transfer mechanism are obstacles thatcontribute to the difficulty associated with developing accurate design models. A few studies have underlinedthe need for new design approaches to strengthening steel members, since the existing designmethods are not accurate enough.The first step towards developing new design models is to study these adhesive joints. This paper dealswith analyses of adhesive joints used to bond CFRP laminates to steel substrates using a numerical andexperimental approach. A numerical study of joints has been made utilizing the FE method, while, in theexperimental part of the study, an optic measurement technique has been used. Different aspects of jointbehavior, such as strain distributions along the bond line and through the thickness of the adhesive layerand failure mechanisms are discussed