This paper presents the results of a comparative study of steel-structured buildings built according to Brazilian standards and their behavior when exposed to fire. An eleven-story building, exposed to different fire conditions was analyzed using both simple and advanced dimensioning analytical methods. The simple approach determines, by means of analytical expressions, the ultimate strength capacity in an elastic domain. The advanced approach uses a numerical tool, Program SAAFE (System for Advanced Analysis of Fire Engineering), developed on the basis of the plastic-hinge theory, which is applied to perform the inelastic analysis of the proposed steel-framed structure under fire conditions. The obtained results are contrasted, taking into account the proposed regulations of the new Brazilian code for steel buildings, making it possible to outline the advantages of considering steel ductility in the current design practice for steel structures under fire conditions.
Steel structures; fire design; nonlinear analysis; plasticity