A new design model for adhesive joints used to bond FRP laminates to steel beams

The strengthening and repair of existing structures using bonded carbon fiber reinforced polymer, CFRP, laminates has attracted a great deal of attention in the past two decades. Investigations clearly indicate the great potential of this method for restoring the capacity of corroded steel beams and improving their fatigue life. One important issue regarding the use of this technique in strengthening steel structures is the design of adhesive joints used to bond FRP laminates to steel substrates. Very limited research work has been conducted in this area and, at the present time, there is a lack of suitable design models for FRP-strengthened steel members. This paper is mainly concerned with a proposal for and verification of a new design model for adhesive joints used to bond FRP laminates to steel beams for strengthening and repair purposes. Quasi-static tests were performed on steel plate and full-scale beam specimens bonded with CFRP laminates to evaluate the new design model proposed in this study. The failure, in all specimens, took place at the steel-adhesive interface. The new design model presented in this paper was found to be accurate in terms of predicting the ultimate load and failure mode of the joints