Combined Torsion, Flexure, and Axial Compression Applied to Concrete-Filled FRP Tubes

St Onge J., Fam A.

10th International Conference on Fibre-Reinforced Polymer (FRP) Composites in Civil Engineering (CICE), İstanbul, Turkey, 8 - 10 December 2021, vol.198, pp.461-471 identifier identifier

  • Publication Type: Conference Paper / Full Text
  • Volume: 198
  • Doi Number: 10.1007/978-3-030-88166-5_39
  • City: İstanbul
  • Country: Turkey
  • Page Numbers: pp.461-471
  • Keywords: CFFT, Concrete, Torsion, Bending, Axial, BEHAVIOR, BRIDGE
  • Istanbul Technical University Affiliated: No


This paper presents the testing results of four concrete-filled fiber-reinforced polymer tubes (CFFT) to evaluate their response under combined axial compression, flexural, and torsional loading. The first three samples evaluated each of the loading states individually, while the final sample tested a combination of all three loads. The presence of the axial compressive force was found to increase cracking strength by 178% in flexure and 105% in torsion while improving load retention after cracking. More importantly, combined loading was found to improve the flexural capacity by 34%, while reducing the torsional strength by 30%. This loading state had little effect on the flexural and torsional stiffnesses along with the maximum flexural deflection but reduced the twist capacity by 68%. Failure in the combined loading state was governed by the rupture of the tube resulting from high longitudinal tension on the bottom surface like in the case of pure flexure.