Análise numérica do ensaio de arrancamento de barras de aço embebidas em concreto autoadensável

Abstract

The existence of reinforced concrete is directly related to adherence, as it is this mechanism that guarantees the reciprocity of materials, concrete and steel, in reaction to the imposed efforts. Generally, the adherence is investigated experimentally from the pullout test, proposed by RILEM-FIP-CEB (1973), which consists in the pullout of a bar positioned in the center of the cross section of a concrete prism. To collaborate with experimental studies perfomed out in the laboratory, numerical analysis can be developed, using the finite element method using the ANSYS program. The technique allows to extrapolate the investigation to other applications with less cost and time. In this research, a numerical analysis was performed based on data from experimental results available in the literature for pulling out 10 mm diameter steel bars, which used self-compacting concrete with compressive strength of 30 MPa. The contact interface between the concrete and the bar is the problem to be solved in the numerical simulations. Therefore, two different approaches were adopted: application of contact elements and material from cohesive zones (CZM), and the model of springs. The numerical results were validated from the experimental data and also compared with a numerical analysis carried out by the same author of the experimental studies. The numerical curves obtained in this work, mainly using the spring model to simulate the contact between the steel and concrete materials, showed a pullout force versus slip curve behavior close to what was experimentally reported and, in addition, the peak pullout force. presentation a maximum difference of 0.80% between the numerical models used in this research and the average force obtained experimentally. Thus, collaborating with the existing numerical analysis of the experimental data used as a reference, since it had underestimated the pullout force by approximately 25.1%, and the numerical curve showed some discrepancies when compared to the experimental curve.