Flexural and Shear Resistance of High Strength Concrete Beams

In the present paper, an analytical model is proposed that is able to determine the shear resistance of high strengthreinforced concrete beams with longitudinal bars, in the presence of transverse stirrups. The model is based on the evaluation of theresistance contribution due to beam and arch actions. For the resistance contribution of the main bars in tension the residual bondadherence of steel bars and the crack spacing of R.C. beams are considered. The compressive strength of the compressed arch is alsoverified by taking into account of the biaxial state of stresses. The model was verified on the basis of experimental data available in the literature and it is able to include the followingvariables in the resistance provision: - geometrical percentage of steel bars; - depth-to-shear span ratio; - resistance of materials; -crack spacing; - tensile stress in main bars; - residual bond resistance;- size effects. Finally, some of the more recent analyticalexpressions able to predict the shear and the flexural resistance of concrete beams are mentioned and a comparison is made withexperimental data.