This research conducted a detailed study of the formation of the isostatic lines in corbel reinforced concrete due to the impossibility of analyzing them by the theory of Euler-Bernoulli as it does not meet some of its assumptions.Once the geometry of the structural element is established, its analysis is carried out by using as programming environments MatLab, Excel, AutoCAD and a finite element commercial modeling program with ANSYS in order to compare and calibrate the models resulting from the two analysis techniques.The result of this investigation established for the family of a plane isostatic stress state since the other component of principal stresses (3) is zero for almost all measuring points and where it was not, its value is negligible.