In-plane structural response and design of steel I-section beam-columns at elevated temperatures

In this paper, the behaviour and design of steel I-section beam-columns in fire are explored. Finite element models capable of mimicking the behaviour of steel beam-columns in fire are developed. Results from fire experiments on steel I-section beam-columns from the literature are utilised for the validation of the finite element models. Extensive structural performance data are generated on the response of steel I-section beam-columns through numerical simulations, considering different cross-section shapes, elevated temperature levels, member slendernesses and loading conditions. The accuracy and safety of the beam-column design methods provided in the current European structural steel fire design standard EN 1993-1-2 and its upcoming version prEN 1993-1-2 are explored. A new fire design method for steel beam-columns that is compatible with the room temperature beam-column design method provided in the European room temperature structural steel design standard EN 1993-1-1 is put forward. The proposed design rules enable the establishment of a consistency between the beam-column design methods of the European structural steel room temperature and fire design standards (i.e. EN 1993-1-1 and EN 1993-1-2), which is currently lacking. The higher accuracy, safety and reliability of the proposed fire design rules for steel beam-columns relative to those given in EN 1993-1-2 and prEN1993-1-2 are verified.