Experimental study on CFRP-strengthened steel beams

Recently, as a viable alternative to strengthening or repairing steel bridges with welded or bolted plates, bonded CFRP plates have been used. The main goal of the presented study is to compare the flexural behaviour of steel beams strengthened with the CFRP plates. The research has evaluated two strengthening schemes: adhesive-bonded passive plates and adhesive-bonded prestressed or active plates. The ductility and yield/ultimate carrying capacity of steel beams as well as the effectiveness of strengthening have been established in each case. The failure modes of the strengthened beams comprised the CFRP plate debonding or plate rupture, depending on the strengthening system (passive or active) and some system parameters, as the CFRP modulus of elasticity, end plate anchoring and plate prestressing level. The influence of these parameters on the strengthening effectiveness has been also discussed.