Beam-columns with Thin Wall Cross-sections in Case of Fire

Abstract

The fire behaviour of class 4 cross-sections beam-columns is investigated in this paper. The local buckling of the cross-sections as well as the global instabilities are evaluated. A numerical parametric study is conducted with the help of different finite element software to analyse the efficiency of current EN 1993-1-2 simple design rules. It is demonstrated that these current simple rules do not allow a cost-effective design of such steel elements. Following the new simple design rules developed in the scope of FIDESC4 project to calculate the effective properties of class 4 cross-sections and the lateral torsional buckling resistance/buckling resistance of corresponding members, a new interaction curve is proposed and the numerical results are now compared with the new obtained resistances. Statistical results are given to approve the new method and show its efficiency in terms of safety level and economic design.