Proposta analítica para estimar as resistências residuais à tração por flexão em concreto reforçado com fibra de aço

Abstract

This research presents equations that estimate the residual resistances, fRi (i = 1 to 4), based on the main parameters that influence the performance of steel fiber reinforced concrete (SFRC), such as the geometric properties of steel fibers, the concrete compressive strength (fc) and fiber volume fraction (Vf). For this purpose, the research was divided into three stages, the first one consisted of creating an extensive and diversified database to, from it, develop the residual resistances equations through multiple regression. The next stage was experimental, composed of 15 beams (150x150x550) mm notched and tested to flexural tension, with variable fiber volumes, with contents of 0.0%, 0.5%, 1.0%, 1.5% and 2.0%. Finally, for the analysis of the equations elaborated in the first step, another database is presented, in which experimental results collected from the literature and those obtained in this research were inserted, and, additionally,performance comparisons were performed with four other existing analytical models. It was concluded that the analytical proposal presented by this study to define the residual resistances, in comparison with the other existing empirical models, stood out for its good performance, since it was the most accurate, less penalized and dispersed, demonstrating the reliability of the equations.