Effect of plate end and adhesive spew geometries on stresses in retrofitted beams bonded with a CFRP plate

Adhesive bonding technique has been widely used in construction as an alternative to conventional joint techniques, particularly in retrofitting schemes using carbon fibre reinforced polymer (CFRP) plates. Spew fillets and end tapers have been suggested for reducing the stress concentration in the adhesive layer of retrofitted beams. In this paper, finite element (FE) analyses were employed to determine the effects of the spew fillet and the taper on interfacial adhesive stresses and the strains in the CFRP plate. A total of eight cases with different configurations of spew fillet and different tapers have been considered. The results largely agree with the findings on lap joints, but the effect of spew fillets is far less than that for lap joints. Moreover, the results show a combination of an inside taper in the plate and a triangular fillet give the most reduction in the maximum interfacial stresses. The results of the FE analyses also show that the effect of spew fillet size on the strain close to the plate end, which confirms previous analytical and experimental results.