Cross-section behaviour and CSM based design of stainless steel I-sections in fire

In this paper, a comprehensive investigation into the cross-section behaviour and design of stainless steel I-sections in fire is carried out. Shell finite element (FE) models able to mimic the cross-section response of stainless steel I-sections at elevated temperatures are developed and validated. An extensive numerical parametric study is then conducted using the validated shell FE models to comprehensively investigate the behaviour of stainless steel I-sections in fire, taking into account 12825 stainless steel I-sections and covering a very broad range of cross-section slendernesses, cross-section geometries, elevated temperature levels and stainless steel grades. Based on the results from the parametric studies, a new version of the deformation based cross-section design approach Continuous Strength Method (CSM) is proposed for the fire design of stainless steel cross-sections. The proposed new version of the CSM is assessed against (i) the stainless steel cross-section design provisions of the European structural steel fire design standard EN 1993-1-2 and (ii) the existing versions of the CSM. The results demonstrate that the proposed version of the CSM offers a very reliable approach to predict the ultimate resistances of stainless steel I-sections at elevated temperatures, leading to more consistent ultimate resistance predictions relative to EN 1993-1-2 and the existing versions of the CSM.