Push-out tests and analytical study of shear transfer mechanisms in composite shallow cellular floor beams

• We investigated shear transferring mechanisms of shallow cellular floor beams.
• Resistance and behaviour of the shear connection were studied in 24 push-out tests.
• Resistance of shear connection is governed by opening diameter and concrete grade.
• Tie-bar and stud greatly increase resistance and ductility of the shear connection.
• A calculation method for shear resistance of the shear connection is established.

The shear transferring mechanisms of composite shallow cellular floor beams are different with the conventional headed shear studs, and have not been investigated previously. This paper presents the experimental and analytical studies of the shear transferring mechanisms with the aims to provide information on their shear resistance and behaviour. The composite shallow cellular floor beam is a new type of composite floor beam that consists of an asymmetric steel section with circular web openings and concrete slabs incorporated between the top and bottom flange. The unique feature of the web openings allows tie-bars, building services and ducting to pass through the structural depth of the floor beam, creating an ultra-shallow floor beam structure. The shear connection of the composite shallow cellular floor beam is formed innovatively by the web openings, as the in-situ concrete passes through the web openings may or may not include the tie-bars or ducting to transfer the longitudinal shear force. In total, 24 push-out tests were carried out to investigate the shear connection under the direct shear force. The effect of loading cycles on the shear connection was also investigated. The failure mechanisms of the shear connection were extensively studied, which had led to the development of a calculation method of shear resistance for the shear connection.