Numerical analysis of cold‐formed steel sigma-shaped beams in fire conditions

Abstract

This paper presents the development of a finite element model for predicting the flexural behavior of cold-formed steel beams subjected to fire and with restrained thermal elongation (different grades of axial and rotational restraint). The numerical simulations were carried out with the finite element software Abaqus/CAE. The numerical model was compared with experimental results in order to validate it for further parametric studies. This paper provides details of the simulation methodology for achieving the numerical stability and faithful representation of detailed structural behavior. To verify the accuracy of the Abaqus model the numerical and experimental results were compared in terms of axial restraining forces, vertical mid-span deflections, critical temperatures and failure modes of the beams. The numerical results showed a good agreement with the experimental ones. However, the critical temperatures determined numerically were slightly lower than the numerical ones in the simply supported and axially restrained beams and the opposite in the axially and rotationally restrained beams, this for both sigma and 2-sigma section beams.