Performance of stirrup-confined concrete-filled steel tubular stub columns under axial loading: A further investigation

Abstract

To investigate the effects of stirrup ratio and connection type of stirrups on axial compression performance of stirrup-confined concrete-filled steel tubular (CFST) stub column, experiments were conducted on 16 CFST stub columns. The axial compressive bearing capacity and ductility of square and circular CFST stub columns with welded and non-welded stirrups were studied. Besides, numerical models of the stirrup-confined CFST stub columns were established to validate whether the numerical modeling method for welded stirrup-confined CFST column is suitable for the non-welded counterparts. Then, the applicability of the formulas for the axial compressive bearing capacity of the large stirrup ratio CFST stub column was investigated. The results indicated that the stirrups have a significant constraint effect on the steel tube and improve the axial compressive bearing capacity and ductility of the CFST stub column obviously. The effects of the stirrups on the square composite column are more significant than the circular composite column. The welded stirrups are more effective on the bearing capacity and ductility. The numerical modeling method and formulas are suitable for the non-welded stirrup-confined and large stirrup ratio CFST stub columns.

Keywords

• Stirrup-confined CFST stub column
• Constraint effect
• Ultimate bearing capacity
• Non-welded stirrup
• Large stirrup ratio