Um Modelo Elasto-Plástico para a Aderência da Interface entre Concreto e Reforςo de Aςo

Abstract

Stress transfer between concrete and steel bars of the reinforcement is a complex phenomena dependent on many variables. Uncountable studies on the subject have been presented by decades, but few are capable of simulating the complex iterations that occur at the interface. To simplify analyses, many models define a priori the sliding versus bonding stress relation of the interface, which depend on several factor, as the concrete confinement. In the model proposed in this work, an elasto-plastic model is used. Yielding/rupture surfaces are defined in the Mohr´s space in order to take into account different fracture modes found at the interface: pull-out, splitting and steel yielding. Softening that follows the damage process is considered. In this case the sliding versus bonding stress relation is obtained automatically as a result of the analyses, capturing, for instance, the effect of concrete confinement. The change from splitting failure to pull-out failure can be also automatically captured by the model. Comparisons of experimental results with simulations made in a finite-element context for a simple pull-out test confirm the adequacy of the model.