Behaviour of Cellular Steel Beams Under Uniform Moment at Elevated Temperatures

Cellular steel beams have proved to be one of the most significant developments in steel construction. The introduction of an opening in the web of a beam alters the stress distribution within the member and also influences its collapse behaviour under the thermal load developed during a fire attack. Behaviour of cellular beams under fire can be predicted by performing simplified coupled (thermal-structural) field analysis. This paper covers the effect of parameters, viz. the span of the beam, size and spacing of the openings (cellularity), and load ratio on the behaviour of cellular beams with hinge–hinge support conditions under a uniform moment and uniform elevated temperature. The present numerical study is based on finite element analysis (FEA) which covers the both geometrical and material nonlinearity. Moreover, in this study, the material degradation at elevated temperature is not considered, and hence, the temperature at which deformations increase rapidly indicates the upper limit of web yield temperature. The result from the present study shows that the cellularity, load ratio, and span of the beam have a significant effect on temperature-deformation behaviour and theoretical web yield temperature of beams.