This paper describes a sequence of experiments on a long-span asymmetric composite cellular beam. This type of beam has become very popular, combining the composite action between the steel and concrete with the increased section depth, compared with more commonly used solid-web I sections. Openings in the steel web also reduce the self-weight and can accommodate the passage of service ducts. Eurocode 4 recommends a high degree of shear connection for asymmetric composite beams despite the practical difficulties in achieving this. Recent research suggests that the required degree of shear connection could be reduced, particularly for beams that are unpropped during construction. However, little test data exists to verify the behaviour of unpropped composite cellular beams. Therefore two series of testswere conducted on a 15.26mlong asymmetric composite cellular beamwith regular circular openings and an elongated opening at themid-span. The degree of shear connection was 36%, less than half of that recommended in Eurocode 4, and the beam was unpropped during construction. The beam was subjected to uniformly distributed loading and shear load during the tests. The end-slip, mid-span vertical deflection, shear connector capacity and strain distribution were examined. The beam failed at an applied uniform load of 17.2 kN/m2 (3.4× design working load 5.0 kN/m2). The member withstood an applied shear load that was 45% higher than predicted, and exhibited a Vierendeel mechanism at the elongated opening. Overall, these tests demonstrated the potential of unpropped composite cellular beams with low degrees of shear connection

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This article reviews the performance characteristics of and some recent developments in slim‐floor and integrated beam construction. This form of construction provides a flat floor using precast concrete slabs or deep composite decking and offers advantages over other forms of construction in many sectors. Composite slim‐floor beams have superior stiffness and can achieve longer spans.

The development of the " CoSFB-Betondübel" is presented in