Flexural behaviour of composite slim floor beams

Composite slim floor beams consist of a steel section embedded in a concrete slab, offering the advantages of a steel-concrete composite structure combined with a reduced floor depth. Several mechanisms contribute to the shear connection in this type of beam, such as headed studs, friction and clamping effects and the using of reinforcement bars passing through holes in the steel beam web. However, to date, nobody has systematically identified these mechanisms and Eurocode 4 does not provide specific design guidance for slim floor beams. A series of shear beam tests and flexural beam tests, using different arrangements of shear connectors, were carried out in order to assess the degree of shear connection and connector capacity in these beams. Most of the specimens used a novel shear connector, comprising a transverse steel bar surrounded by concrete, passing through a hole in the steel section web. This paper presents the findings from the flexural beam tests and draws comparisons with those from the previous shear beam tests. Numerical models will be developed in future to extend the data and include a wider range of parameters. The data will also be used to improve understanding of this type of beam and will lead to the provision of specific design guidelines for slim floor beams.