Retrofitting of shear damaged RC beams using diagonal CFRP strips


JOURNAL OF REINFORCED PLASTICS AND COMPOSITES, vol.30, no.17, pp.1495-1507, 2011 (SCI-Expanded) identifier identifier


The results of an experimental investigation for the retrofitting of shear-damaged RC beams using diagonal CFRP strips are presented in this article. The experimental study consisted of seven shear-deficient, T-cross-sectioned, 1/2-scale, simply supported beam specimens. One beam is used as the reference specimen. The remaining six specimens are tested in two stages. At the first stage, specimens are shear damaged severely and the shear-damaged RC beams are retrofitted using diagonal CFRP strips by wrapping them around the beam in the shape of a 'U'. Then, retrofitted beams are tested to failure. In this study, 50mm wide CFRP strips are used with three different spacings such as s(f) = 125, 150, and 200 mm. One of the two specimens with the same spacing is tested with anchorages at the ends of the CFRP strips. Although the strips without anchorages improved the shear strength of the shear-damaged beam, they could not prevent the shear failure. Shear-damaged specimens that are retrofitted with anchoraged CFRP strips showed to improve the shear strength, and ductile flexural behavior was observed in them. When the CFRP strains of the strips with and without anchorages are compared, maximum strains at anchoraged strips are approximately 1.55 times larger than those without anchorages. Calculated shear load carrying capacity of the specimens, according to ACI 440 and FIB regulations, are approximately 2% larger than the experimental one.