Análise numérica de colunas estaiadas e protendidas em aço carbono e aço inoxidável

Abstract

The load-carry capacity of slender columns is limited by global instability. Nevertheless, by adding a set of cross-arms and prestressed cable, the horizontal displacement due to the buckling phenomenon can be reduced, and, as a result, the load capacity is considerably increased. In addition to the load capacity increment, the architectural aesthetics, assembly process and the cost-benefit factor has aroused the interest of engineers, architects, and researchers in the theme. Even though it has been a well-known structural system since the ‘60s, there are still many studies in development, such as stability, the number of crossarms and guidance for the analytical design. In most of the studies in the literature, carbon steel was the main material used, and the present study will also be evaluating stainless steel in the structural behaviour. The main objective of this study is to evaluate and compare the behaviour between carbon and stainless steel and later compare the results with analytical methods to obtain the load capacity. The numerical model was calibrated from experimental tests carried out with stainless steel columns and was able to reproduce the capacity and stiffness behaviour. A parametric study was carried out to expand the analyzes to other sets of elements, column, cross-arm and stay and later compare the results with the design methods present in the literature. The parametric study has shown that the stiffness of the stays is the main element contributing to the increment of load capacity., Depending on the selected elements, the structural system may be underused. Furthermore, it was identified that the greater the slenderness of the column is, the greater the tendency of the material to behave in the elastic regime of the material stress versus strain curve. Finally, the analytical design based on existing methods was evaluated, and a modification in the existing formulation was proposed, aiming at a better approximation of the obtained numerical results.