Analysis of a straight free-standing stair in reinforced concrete through analytical and numerical models via Finite Element Method
DOI:
https://doi.org/10.33448/rsd-v11i8.30842Keywords:
Free-standing stairs; Finite Element Method; Bending moment; Deformations.Abstract
Special stairs have gained more space in structural projects in recent times. The calculation structural models used for these stairs must portray the behavior at failure (ELU) and in service (ELS) and can be generated through simplified analytical models or with the use of numerical methods. In this perspective, this article presents the analysis of free-standing stairs in reinforced concrete through slab thickness variation and the obtainment of normal bending forces and deformations. For that, the analytical methods of Knijnik & Tavares (1977) and Araújo (2014) were used, as well as the Finite Element Method (FEM), with the help of the structural analysis program SAP2000®. Computational models composed by bar and shell elements were evaluated. From the simulations carried out, a satisfactory approximation between the analytical and numerical models with shell elements was observed, while the models formed by bar elements presented negative bending moments higher than those observed in the other two models. Furthermore, it can be verified, through the models with shell elements, in the central region of the landing next to the flights, the existence of bending moments concentration points, indicating the need for a complementary reinforcement in this region. Finally, it was observed that, for smaller thicknesses, the analytical method presented greater deformations, followed by the numerical model formed by bar elements and, finally, the model with shell elements. However, as the thickness increased, there was convergence of results between the analytical and numerical models analyzed.
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