# Mechanical properties of concrete filled steel tube members constrained by carbon fiber reinforced materials under bidirectional coupled loading

## TL;DR

This paper studies how carbon fiber reinforced materials affect the strength of concrete-filled steel tubes under combined bending and twisting forces.

## Contribution

The study introduces new equations for predicting the strength of CFRP-concrete filled steel tubes under combined bending and torsion.

## Key findings

- Nine specimens were tested to analyze the torque-angle behavior of CFRP-concrete filled steel tubes.
- A finite element model was developed and validated for numerical analysis of the specimens.
- Equations for bearing capacity under combined bending and torsion were derived based on experimental and numerical results.

## Abstract

Carbon fiber reinforced composite structures have been a research hotspot in recent years, with 9 specimens designed for static tests under bending and torsion loads of CFRP concrete filled steel tubes. The torque angle (T-θ) curve was studied from an experimental perspective. Subsequently, a reasonable finite element model was established using ABAQUS software. In addition, the effects of changes in parameters such as the number of steel concrete strength, bending ratio, and steel ratio on C–CF–CFRP-ST bending and torsion specimens were studied through numerical parameter research. Finally, equations of bearing capacity of CFRP-concrete filled steel tube under coupled bending and torsion are proposed.