Resistance and behaviour of carbon steel and stainless steel columns with axial and rotational end‐restraints in fire

Abstract

AbstractDue to the presence of neighbouring structural elements, carbon steel and stainless steel columns are typically axially and/or rotationally restrained at their ends in fire. Despite the significant influence of the axial and rotational end‐restraints on the behaviour, the fire design rules for steel columns provided in the European structural steel fire design standard EN 1993‐1‐2 were originally developed considering the structural response of axially unrestrained steel columns with pin‐ended support conditions. Thus, EN 1993‐1‐2 may provide inaccurate ultimate resistance predictions for axially and/or rotationally restrained steel and stainless steel columns in fire. Considering this, this paper investigates the behaviour and design of carbon steel and stainless steel columns with axial and/or rotational end‐restraints at elevated temperatures. A number of carbon steel and stainless steel I‐section columns are considered, taking into account different axial and rotational end‐restraint stiffnesses, room temperature loading ratios, member and cross‐section slendernesses. A new design method for the fire design of axially and/or rotationally restrained steel and stainless steel columns is put forward. The accuracy of the proposed new design method is extensively verified against the results from nonlinear shell finite element modelling.