Stainless steel is known to have a better behaviour at elevated temperatures than carbon steel. This, combined with its aesthetic appeal and corrosion resistance, makes stainless steel structures an attractive alternative to carbon steel structures. However, EN 1993-1-4 does not establish de-sign rules associated with global analysis of stainless steel frames and EN 1993-1-2, devoted to carbon steel, provides a conservative approach for the fire design of stainless steel structures. Hence, current European codes do not provide efficient design guidelines for stainless steel frames subject to fire and therefore the response of this type of structures should be assessed by means of experimental tests and/or numerical analyses. The main objective of the paper is to assess the nonlinear structural response of stainless steel frames subjected to fire, focusing the investigation on the influence of the degree of utilization. A comprehensive numerical analysis on Class 1 and Class 3 stainless steel frames and Class 1 carbon steel frame subjected to fire is carried out varying the degree of utilization. Calibration of the FE models has been carried out as a part of a study of transient thermo-mechanical models, which are needed to assess the response of stainless steel frames subjected to fire.The authors acknowledge the funding from the MINECO (Spain) un-der Project BIA2016-75678-R, AEI/FEDER, UE “Comportamiento estructural de pórticos de acero inoxidable. Seguridad frente a ac-ciones accidentales de sismo y fuego”.Peer ReviewedPostprint (author's final draft
