Load-reversed push-out tests on rectangular CFST columns

Xiushu Qu, Zhihua Chen*, David A. Nethercot, Leroy Gardner, Marios Theofanous

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

28 Citations (Scopus)


Load-reversed push-out tests have been carried out on 6 rectangular concrete-filled steel tubular (CFST) columns with the aim of investigating the nature of the bond between the concrete infill and the steel tube, the contribution of each bond stress component (i.e. chemical adhesion, microlocking and macrolocking) and the development of macrolocking within four half-cycles of loading. The contribution of microlocking to the total bond strength was obtained from the comparison between the ultimate strength of normal specimens and lubricated specimens, which also revealed the detrimental effect of lubrication on the bond strength. The macrolocking contribution was obtained from the comparison between the ultimate strength achieved in the first half-cycle of loading τu1 and the ultimate strength achieved in the third half-cycle of loading τu3 of the non-lubricated specimens. The developed bond mechanisms were explained and details of the interface bond stress distribution were obtained from the recorded axial strain gradients in the steel tube. Finally, the concept of a critical shear force transfer length was introduced, and its implications on practical design discussed.

Original languageEnglish
Pages (from-to)35-43
Number of pages9
JournalJournal of Constructional Steel Research
Publication statusPublished - 2013
Externally publishedYes


  • Concrete-filled steel tubes (CFST)
  • Interface bond strength
  • Interface condition
  • Load-reversal
  • Macrolocking
  • Microlocking
  • Push-out test

ASJC Scopus subject areas

  • Building and Construction
  • Civil and Structural Engineering
  • Mechanics of Materials
  • Metals and Alloys


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