Previsão da resistência à fadiga de vergalhões utilizando as curvas S-N: estudo da influência do diâmetro e do processo de fabricação

Abstract

Before the fatigue effect became an object of study in the Brazilian norms, there were already structures such as bridges requested by this effect. The rebars used in the construction of the bridges, when requested by fatigue, can end up breaking internally and causing a collapse of the structure without prior notice. To prevent this macro effect, it is necessary to understand the behavior of fatigue in its simplest form: the agents that will influence the fatigue resistance of the rebar used in the bridge. In this work, fatigue life will be predicted by studying the influence of the diameter and the manufacturing process. For this, S-N curves were constructed based on data collected in the bibliography and compared their results among themselves and between Brazilian and European standards. Rebar that had a diameter of less than or equal to 16mm, obtained resistance to fatigue superior to rebar with diameter above 16mm. Tempered and tempered rebars obtained their resistance to fatigue, superior to those of other manufacturing processes. The hot-rolled and cold-worked bars, although having the same microstructure, obtained different strengths that can be attributed to the carbon content in the rebar used as data.