A new design model for adhesive joints used to bond FRP laminates to steel beams - Part A: Background and theory

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. A large number of concrete structures all over the world have been strengthened and repaired using this technique. In recent years, there has also been a trend towards using this method to upgrade steel structures. 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, which consists of two parts, 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. The first part of the paper reviews the existing design methods and presents the background to the new proposed model. The second part of the paper deals with experimental work undertaken to verify the new model