Cellular beams are the preferred form of long span construction in multi-storey buildings. For efficient design of composite cellular beams, asymmetric sections are often manufactured in which the bottom flange is larger than the top flange. A further innovation is in the use of 80mm deep deck profiles which allows beam spacing to be increased to 4.5m, and so the effective slab width acting compositely with the long span beams is also increased. The values for shear connector (stud) resistance given in Eurocode 4 (EN 1994-1-1), when used in combination with these modern decking profiles, have led to problems in achieving the minimum degree of shear connection for composite beams in comparison to the former BS 5950-3. For secondary beams, the number of shear connectors that can be accommodated in a span is limited by the spacing of the deck ribs (typically 300mm for deep trapezoidal profiles), and it is found that even for pairs of shear connectors per deck rib, it is impossible to satisfy the shear connection rules in Eurocode 4 for long span asymmetric beams. SCI, with support from the Research Fund for Coal and Steel, is on the way to resolving this problem in design to Eurocode 4, and has completed a test on a 15.3m composite cellular beam at the University of Bradford. This is believed to be the longest composite cellular beam test ever carried out. The test was part-sponsored by ASD Westok.

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