Simulação numérica da influência de aberturas no comportamento estrutural de vigas de concreto armado em pilotis de edifícios

Abstract

The integration of openings in reinforced concrete beams has become a prevalent practice in buildings with stilts, a development largely attributable to the high concentration of installations in these structures. However, such openings have the potential to compromise the structural performance of beams, particularly with regard to shear resistance. The present study evaluated the impact of horizontal openings near supports in reinforced concrete beams using numerical simulations in ABAQUS® software. The Concrete Damaged Plasticity (CDP) constitutive model was employed to conduct these simulations. A comprehensive analysis was conducted to assess the impact of variations in support types (double-supported and double-fixed), vertical positions (H20, H37, and H60), and opening dimensions (15x15 cm, 15x30 cm, and 15x45 cm). The numerical outcomes were then juxtaposed with the established standards delineated in ABNT NBR 6118 (2023), which stipulates the criteria for evaluating the strength of beams with dimensions of 15x15 centimeters. The comparative analysis revealed a decline in the maximum strength of these beams, ranging from 1% to 4%. Conversely, the openings measuring 15x30 cm and 15x45 cm resulted in losses of 11% to 15% and 17% to 32%, respectively. The H60 position exhibited the optimal performance, irrespective of the initial size of the opening. It was observed that beams with fixed support withstood greater loads than those with double support, thereby highlighting the role of connection in the rigidity of the system. Furthermore, it was observed that the introduction of apertures modified the failure mode of the beams, promoting brittle shear failures, since the shear stress exceeded the bending moment as a limiting factor. In light of the aforementioned findings, it was deduced that these conclusions served to underscore the necessity of incorporating stiffness compensation into the structural design of beams that are subject to openings. This approach contributed to the development of safer and more effective solutions.