Some issues on the strengthening of steel structures with fibre-reinforced polymer materials

Fibre-reinforced polymer (FRP) materials are widely accepted in the strengthening of civil engineering structures due to their unique characteristics such as high mechanical properties, low dead weight and very good corrosion resistance. In particular the use of FRP materials for strengthening concrete structures was deeply investigated in the past. More recently the use of FRP materials was also proposed in the strengthening of timber, masonry and steel structures. Several studies have been conducted in the literature on the reinforcement of steel structures by FRP materials. They include bond strength, fl exural and fatigue reinforcement, strengthening against local buckling and durability aspects. Future research should be conducted in order to propose more reliable design guidelines and to fi nally increase the acceptance in practice of this reinforcement technique. This paper illustrates some issues on the strengthening of steel structures with FRP materials starting from previous works from the authors. The paper starts with a discussion on the benefi ts and drawbacks in the use of FRP materials in the reinforcement of steel structures. Then some issues concerning the reinforcement of steel structures are illustrated. They include bond behaviour between steel and FRP, fl exural strengthening of steel beams including the post-yielding behaviour and bond durability under mechanical (fatigue) and environmental actions.