On the behaviour of R/C beams without shear reinforcement

The behaviour of beams without shear reinforcement has been analysed through a non-linear finite element procedure, in which a constitutive model recently proposed by the Authors, (PARC), has been implemented into a FE program. The stiffness matrix has been evaluated assuming non-linear orthotropic relationships for plain and reinforced concrete, subjected to plane stresses. The main contributions to shear strength after cracking, such as dowel action, aggregate interlock, bridging effect, compression of concrete struts, have been taken into account. The plane stress analysis has been conducted adopting a mesh of quadratic membrane elements, representing the middle plane of the section. The proposed formulation has been verified by performing comparisons with well-documented experimental tests reported in scientific literature. The non-linear analysis has been able to accurately represent the response of the structures to the applied loads, and to investigate the influence of each stiffening contribution on the shear resistance evaluated at a given cracked vertical section.