Analisi non lineare di travi in cemento armato non armate a taglio

A theoretical model is presented for describing the behaviour of shear critical beams without web reinforcement. The proposed formulation refers to “PARC” constitutive model, which is a smeared, fixed crack model for cracked reinforced concrete elements subjected to in-plane stresses. Advancements, with respect to this theory, have been introduced, in particular in the uncracked stage, considering the nonlinearity of the material subjected to a biaxial state of stress, and in the definition of the crack spacing. The proposed procedure, based on a secant-stiffness approach, has been implemented into a finite-element program, in order to simulate experimental tests carried out on beams containing no transverse reinforcement. The non-linear finite element analysis is shown to accurately model the response of the examined beam specimens, in terms of displacements, strains, width and pattern of cracks. In addition, comparisons with the provisions supplied by European codes (EC2) have been carried out.