Resumo

JUAREZ, C. A. et al. Comportamiento analítico-experimental a cortante en vigas de concreto fibroreforzado. Concr. cem. investig. desarro [online]. 2015, vol.6, n.2, pp.64-79. ISSN 2007-3011.

In this research work, an analytical-experimental comparison of the shear behavior under diagonal tensile stresses is presented for a set of 32 partially fiber reinforced concrete beams. Additionally to the reference (Vf = 0 %), three fiber volume fractions (0.5, 1.0, 1.5 %) were studied for two water/cement ratios (w/c) = 0.55 and 0.85. In total sixteen beams were casted by duplicate, 8 with stirrups and 8 without stirrups. Flexural strength results for shear reinforced and non-reinforced beams were considerably higher that the estimations from ACI 318 equations. Procedures for theoretical predictions of the shear strength were also evaluated trough a comparison of three mathematical models obtained from reference literature (Imam, Swamy y Narayanan) with the obtained experimental diagonal tensile stresses. In comparison with the ultimate shear strength of the beams, results illustrate that these models adequately predict the effect of parameters as: w/c ratio, Vf, contribution of the steel bars length and presence of stirrups. In comparison with the experimental results the model proposed by Imam resulted less conservative because the predicted values were higher than the experimental values, while Swamy and Narayanan models provided conservative and more proximate values.

Palavras-chave : fiber reinforced concrete; beams; shear strength; analytical model; stirrups; steel fibers.