Análise numérica de viga de concreto armado de ultra alto desempenho reforçado com fibras no software Abaqus

Abstract

With the technological development of construction methods, there is an increasing demand for mechanically and chemically superior materials as to enable more efficient, safe and cheap applications. In the last decade Ultra high performance concrete has been the subject of many studies in order to disseminate its use in several applications around the world. By adding fibers in the concrete matrix, it is possible for the element to resist stresses even when fissured through the phenomenon of sewing associated with the presence of fibers that act as bridges distributing the stresses across the crack and ensuring an increase in overall ductility. In this work, the author aims to characterize ultra high-performance concrete reinforced with fibers through the use of a computational model based on finite element analysis and experimentally validated of a rectangular simply supported beam with longitudinal reinforcement under bending stress. Furthermore, another objective of this study is to compare the behavior of the proposed model with the expected behavior in two calculation models used in the design fiber reinforced concrete structures presented in Brazilian standard NBR 16935 (2021) (rigid model and linear model) comparing values of moment, tension distribution and deformation in the most stressed section. Using the Concrete Damage Plasticity material in the Abaqus CAE package, the model was implemented successfully and validated using experimental test data available in literature. The results of this research demonstrate that the behavior observed in the proposed model did similar to what was expected in relation to deformations in the section and pointed to a conservative trend in the plastic model, since there was a significant discrepancy between its resistant moment value and the one extracted from the numerical model. With regard to the distribution of stresses, it was observed an interesting relationship between stress and strain in the tensioned part of the section, where the stresses remained constant while the deformations increased linearly as it approached the most tractioned face.