Adhesive bonding in steel beams strengthened with CFRP

The strengthening of metallic beams with a bonded carbon-fibre-reinforced polymer (CFRP) plate has found many applications in bridge and building structures in recent years. The structural behaviour of the adhesive bonding in this technique is the most distinct element to be considered. In this paper, previous analytical, experimental and numerical studies under static and fatigue loadings by the present authors are reviewed. An S-N curve based on the peak interfacial stresses is proposed to predict the fatigue life to crack initiation of the retrofitted beams. An equation to predict the fatigue life during the crack propagation has also been developed. Finally, the geometric effects of the spew fillet and of the taper at the plate end of the retrofitted beam are discussed. In the conclusion, design recommendations for steel beams strengthened by bonded CFRP plates are detailed based on the findings obtained from the studies presented.