A REGULARIZED BEAM FINITE ELEMENT BASED ON A DAMAGE-PLASTIC MODEL FOR THE ANALYSIS OF R-C FRAMES

In this paper a new beam finite element is presented, for the analysis of the cyclic response of reinforced concrete frames under static and dynamical loadings. A generalized section constitutive law is proposed, based on a damage-plastic model, describing the damaging process of the brittle cementitious matrix and the ductile behavior of the reinforcements. The beam element is formulated via a force-based approach, so that the equilibrium along the element is always satisfied. Furthermore, a simple regularization technique is proposed to overcome the localization problems connected with the softening constitutive behavior, and in order to obtain objective numerical results. A numerical solution algorithm, based on an iterative element state determination and a predictor-corrector procedure at the section level, is developed and some numerical applications are presented.