Avaliação de cantoneiras em aço inoxidável submetidas à compressão axial

Abstract

The stainless steel has been increasingly used in civil construction due to its characteristics of strength, corrosion resistance and durability, as well as its aesthetic and sustainable appeal. However, the current standards for this material were obtained by analogies with the behaviour of carbon steel, and do not usually differentiate among the various types of stainless steel. This study presents an extensive numerical analysis of hot-rolled equal-leg angles subjected to axial compression, adopting austenitic, duplex and ferritic steels. This choice was made because the equal-leg angle columns can develop flexural minor-axis buckling or flexural-torsional buckling, a phenomenon that mixes two pure buckling modes (torsional and flexural major-axis). In the numerical analysis, characterization curves obtained experimentally in other studies were adopted, and the calibration was materialized by the introduction of imperfections to the model, seeking to obtain consistent values, based in tests already performed. Subsequently, the analysis program was expanded to include 31 commercial sections. By comparing the results of the numerical analysis to the normative prescriptions, it was concluded that the current procedures, in general, underestimate the strengths of austenitic and duplex steels but overestimate the strength of ferritic steel. Therefore, some changes were proposed for each type of stainless steel, considering the two buckling modes that could happen. This proposal achieved very accurate results, close to the ones obtained in the numerical analysis, and corrected some problems of the current standards, both for flexural buckling and flexural-torsional buckling.