Performance of the High-Strength Self-Stressing and Self-Compacting Concrete-Filled Steel Tube Columns Subjected to the Uniaxial Compression

摘要

To improve the compactness of concrete and prevent the debonding between steel tube and concrete core, a high-strength self-stressing and self-compacting concrete-filled steel tube (HSS-CFST) column is introduced. This paper deals with an experimental study on the uniaxial compression of HSS-CFST. A total of 51 specimens subjected to axial compression were investigated. Important variables, including self-stress level, concrete strength, tube thickness, and length-to-diameter ratio, were studied. The failure modes, ultimate bearing capacity, and post-peak ductility were analyzed. The results showed that the use of HSS concrete in CFST yielded a better uniaxial compression performance in comparison with the conventional CFST specimens. An increase of 12.4% in ultimate bearing capacity was observed for an HSS-CFST specimen having a self-stress of 5 MPa. The improvement becomes more pronounced as the length-to-diameter ratio increases. Besides, increasing concrete strength can also contribute significantly to the ultimate bearing capacity, while improvement on the post-peak ductility is not obvious. Furthermore, a numerical analysis considering the self-stressing was carried out, which provided good agreement between the experimental results. Finally, predictive equations specially to calculate the ultimate bearing capacity of HSS-CFST columns were proposed and then validated by the experimental results.