Comparativo de modelos de previsão da fluência do concreto apresentados na NBR 6118 (2014) e no ACI 209-R (2008)

Abstract

Creep is a detrimental concrete phenomenon defined as the incremental deformation of a structural member when submitted to a constant tension over time. Many are the factors that influence its development, such as humidity, temperature and cement type. As a result of its multiple influential factors, an equation that can accurately predict the deformation of a structural element could not be found yet. But, there are some prediction models proposed by internationalsand national standards. Therefore, one of the goals of this paper is compare the prediction models presented by American and Brazilian standards, both between themselves and with experimental results. Furthermore, present how the above parameters affect this phenomenon. Another issue considered on this paper is the using of numerical modelling to predict the behavior of the concrete structures, which needs a reliable prediction model to reproduce the physical phenomenon. After verify that the American prediction model provides the closest results to the experimental values, it was implemented in an application developed using Fortran and the Finite Element Method. After the implementation, it was verified whether the values predicted by the application were the same or closed to the ones given by the electronic spreadsheet. It could also be concluded that the humidity is the factor that more influences on creep deformation and how bigger the humidity is, smaller is the deformation.