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

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

Post-fire Behaviour of Innovative Shear Connection for Steel-Concrete Composite Structures

YesSteel-concrete composite structures are commonly used in buildings and bridges because it takes advantage of tensile strength of steel and compressive strength of concrete. The two components are often secured by shear connectors such as headed studs to prevent slippage and to maintain composite action. In spite of its popularity, very little research was conducted on steel-concrete composites particularly on headed stud shear connectors in regards to its post-fire behaviour. This research investigates the post-fire behaviour of innovative shear connectors for composite steel and concrete. Three type of connectors were investigated. They are headed stud shear connectors, Blind Bolt 1 and Blind Bolt 2 blind bolts. Push-out test experimental studies were conducted to look at the behaviour and failure modes for each connector. Eighteen push tests were conducted according to Eurocode 4. The push test specimens were tested under ambient temperatures and post fire condition of 200˚C, 400˚C and 600˚C. The results in ambient temperature are used to derive the residual strength of shear connectors after exposing to fire. Findings from this research will provide fundamental background in designing steel-concrete composites where there is danger of fire exposure

Ultra-high strength concrete filled composite columns for multi-storey building construction

10.1260/1369-4332.15.9.1487Advances in Structural Engineering1591487-1504ASED