Análise da eficiência de Concreto Reforçado com Fibras em pilares submetidos à Flexão Composta Reta

Abstract

The incorporation of fibers to conventional concrete aims to improve the post-cracking resistance of a structural part, because the fibers contribute to the particles of the concrete remaining together, minimizing, in this way, the concentration of stresses caused by cracking and consequently increasing the tenacity of the composite. Fiber Reinforced Concrete (CRF) works efficiently when the composite structural element of this material is

subjected to traction, however it does not have the same effectiveness when it comes to compression. Thus, there are still few scientific studies related to the use of CRF in pillars–in which the predominant effort is compression–when compared to studies related to beams, in which the dominant effort is flexion. However, when the transmitted forces are not centered on the center of gravity (CG) of the pillar, as is the real case of buildings, tensile efforts are generated. Therefore, in the course of the reference work, the behavior of CRF composite pillars submitted to Straight Composite Flexion in the Last Limit State (ELU) is studied, verifying if, at the end, the fibers are favorable to the resistant capacity of the cross-section of the column. At first, information related to fibers, CRF and straight composite flexion is presented and, later, the use of CRF in pillars is evidenced in the described situation. The elaboration of a spreadsheet and the plotting of comparative graphs, based on the Rigid-Plastic Model, contribute to the visualization of the increase in the value of the resistant bending moment when compared to the fiberless concrete and demonstrates that the higher the fiber content, the greater the bending resistance of the element.