Experimental and Numerical Modelling of Cellular Beams with Elongations Openings at Elevated Temperature

The growing popularity of the use of Cellular steel beams in composite floors comes at the same time as an increasing attention to the fire safety engineering design. The recommendation for their design in fire limit states remains very primitive and this is due to the lack of general research in this area. In fire, the temperature distribution across a composite member is non-uniform, since the web and bottom flange have thin cross-sections and a greater exposed perimeter than the top flange. The deterioration of the material properties of the web will therefore become an important effect on the overall performance of the member in the event of fire. This work describes an experimental and numerical study at elevated temperatures on the behaviour of full scale composite floor cellular steel beams with elongation openings. A total of three specimens, comprising three different steel geometries and loading conditions were tested at elevated temperatures. All beams were designed for a full shear connection between the steel beam and the composite slab using shear studs. Finite element models are established with both material and geometrical non-linearity using shell elements and solid brick element to compare the experimental results. This paper will also demonstrate the capability of the developed simple design approach in comparison with numerical modelling, experimental tests and existing design software used by the Steel Construction Institute (SCI).