Analytical study on the composite behavior of rectangular CFST columns under combined compression and torsion

Abstract

In this paper, a total of 44 rectangular CFST column finite element models are established and verified. The effect of loading path, the working mechanism and the constraint interaction of rectangular CFST column under compression-torsion loading are discussed. The obtained results show that the ultimate axial bearing capacity of CFST column is decreased when the torsional moment is applied first, and the ultimate torsional capacity is increased when the compression force is applied first. The working mechanism of the compression-torsion CFST column can be simplified as unity of “pulling/compressive torsion” of the steel tube and “compressive torsion” of the core concrete. Finally, the torque-axial force correlative formula of rectangular CFST column is proposed, and is verified well with the test results and finite element results with higher accuracy and less dispersion.

Keywords

• Concrete filled steel tube
• Compression-torsion
• Finite element
• Ultimate strength
• Loading path