Estudio del comportamiento del hormigón armado ante esfuerzos normales y tangentes mediante modelos seccionales de interacción completa

Abstract

Frame structural analysis has been traditionally based on classic beam theories whose starting hypotheses imply the existence of solely normal stresses in the cross-section or, in some cases, shear stresses in simplified fashion. These methods have been satisfactorily used in the nonlinear analysis of structures dominated by normal forces. Further, there have been many intends to directly extend them to non-linear analysis of concrete structure under more general loading where the theories cannot be applied in a general fashion due to the inclined cracking and anisotropic material behavior. Hence, real structural response under important shear, torsion or confinement cannot be suitably reproduced by traditional beam methods. In this paper, the advantages of frame element idealization of structures are analyzed and the applicability range of traditional schemes considering only normal stresses is defined. A sectional model capable of reproducing 3D stress states in the cross-section domain is briefly presented and used to analyze the response of sections and continuous structures under load cases influenced by tangential forces and confinement. It should be highlighted that the real distribution of normal stresses may be modified in the cracked zone of the beam and affect the structural stiffness. Hence, a shift in the stresses of transverse reinforcement under concomitant bending moments with shear is to be noted as the reciprocal manifestation of the well-known shift of stresses in the longitudinal reinforcements. On the other hand, the model allows a more realistic representation of actual shear patterns of beams and evaluation of actual rotation capacity on length of plastic regions.