In the present investigation, the importance of correctly estimating the stiffness of the shear of reinforced concrete beams was taken into account, taking into account the effect of the shear fortune on the rigidity in reinforced concrete beams, on the other hand the rigidity was determined. obtained by testing a beam an experimental reinforced concrete beam with reinforcements at different distances of 4, 7, 9 and 11 cm. The rigidity in the experimental shear of a reinforced concrete beam and elaborated under the norm. To evaluate these hypotheses, samples formed by 4 groups were evaluated, each one of 5 reinforced concrete prismatic beams, with abutment separations of 4, 7, 9 and 11 cm respectively for each group. The samples were subjected to a 3-point bending test; using the 60-ton Tecno Test test machine and the effort and displacements were obtained for each instant of the test. W...