Estudo numérico do reforço de vigas mistas de aço e concreto com polímeros reforçados com fibra de carbono

Abstract

With the crescent emphasis of steel and steel-concrete composite structures in Brazil, it’s evident that there will be a need to reinforce a crescent number of these structures, with the objective of ensure the durability and performance of buildings. Currently, the strengthening has two methods: the conventional one, which involves the cutting and replacement of steel plates or the addition of external plates to the steel profiles, and strengthening with fiber reinforced polymers (FRP), which still is a theme rarely explored in Brazil. In this field, the present work aims to study the structural behavior of steel-concrete composite beams strengthened with carbon fiber reinforced polymers (CFRP), through the development of numerical models and the study of an analytical model proposed in the reference. The numerical models developed were based on references available in the literature and were adjusted to simulate the beams studied experimentally and analytically in other works. Steel I-sections beams were modeled together with a concrete slab, considering situations of un-strengthened and strengthened beams with CFRP on the lower surface of the tension flange of the steel profile. All beams were subjected to a four-point loading system. To simulate the beams, the ANSYS software was used, which is based on the finite element method, for three-dimensional modelling and static and non-linear physical structural analysis. For the study of the analytical model, a spreadsheet for calculation automation was developed. The results obtained by the numerical simulation consist of displacement in the middle of the beams spans versus applied force, as well as the ultimate vertical load results obtained for the models analyzed. These results were satisfactory and allowed to validate the numerical models developed through the comparison with the experimental results of the references. The results obtained for the resistant moment of the composite beams by the study of analytical model were compared with those provided by the reference. The analytical model studied proved to be reliable for the calculation of the resistant moment of steel-concrete composite beams strengthened with CFRP.