Structural fire design of SHS, RHS and CHS high strength steel columns

Abstract

Despite substantial progress in recent years to improve the design guidance for high strength steel (HSS) structural elements, this has mainly been for ambient conditions with their fire response still in need of further research. Accordingly, this paper reports on an investigation into the structural performance of unprotected HSS hollow section columns in fire. Finite element models of columns made from square, circular and rectangular hollow sections are developed and are validated against test data at ambient and elevated temperature. The validated models are employed to perform parametric studies to assess the influence of a range of variables such as the grades of HSS, levels of temperature exposure and cross-sectional geometry. The structural fire design resistance method for a column given in the Eurocode is assessed based on the FE results. Consequently, new buckling curves are proposed, which provide a more accurate prediction of the real capacity and reliability analysis is also performed on the new proposed design formulations.