RESISTANCE OF CONCRETE-FILLED STEEL TUBES TO PUSHOUT FORCES

Pushout tests have been carried out on 56 concrete-filled steel hollow section tubes. Square and circular sections were used in this series, and the same concrete mix was used throughout the experimental programme. All specimens were 450mm-long, and the steel-concrete interface was about 400mm-long. The tested specimens consisted of an equal number of square and circular steel hollow section tubes. The load was applied at the top of the specimens on the concrete core, and was resisted either by resting the steel section on its base, through the use of brackets welded to the sides of the steel specimens, or through thick plates welded to the sides of the steel hollow sections. Specimens were tested both with and without the use of mechanical shear connectors. The test results showed clearly that the resistance of the specimens to the pushout load is a function of the shape of the steel hollow section used, the type of shear connectors employed, and also the way in which the load is applied to the steel section. (A)