Numerical modeling of reinforced concrete beams considering the effect of metallic fibers on ductility in the ULS: coupled approach via one-dimensional MEF and Mazars damage model

Abstract

Concrete is the most used material in construction around the world. The characteristics of this material provide great advantages compared to other materials due to its great capacity to assume different architectural forms, good resistance to water action, and low relative cost. Structural designs have several requirements to consider the structure is safe. Among the requirements to guarantee the safety of the structure is ductility, which is a measure of the structure's deformation capacity before failure. Ductility is an important structural property in order to achieve an adequate mechanical behavior since, in addition to allowing large deformations before failure, it contributes to the effort redistribution process. An alternative to improve the ductility of structural elements is the addition of fibers, which help in the process of resistance and also in reducing the propagation of cracks, providing greater durability. The behavior of fiber-reinforced concrete elements is extensively studied and several constitutive models have been proposed. However, much of it has an empirical character, which generates limitations, requiring an analytical model that faithfully and generally reproduces the tensile behavior of fiber-reinforced concrete. This proposal aims to contribute to the formulation of a tensile constitutive model for fiber reinforced concrete, combining it with a mechanical model based on the one-dimensional Finite Element Method with non-linear material behavior for the study of the ductility of fiber reinforced concrete beams. The effect of the fibers will be considered from the calibration of the internal parameters of a damage model to represent the concrete, having as reference the developed tensile constitutive model. Different combinations of concrete compressive strength, relative neutral axis position and volumetric ratio of metallic fibers will be analyzed to determine the effect of fibers on the ductility of reinforced concrete beams reinforced with metallic fibers. (AU)