Analytical Investigation of Circular Concrete-Filled Steel Tabular Column

Abstract

This study presents an in-depth experimental and numerical investigation of Concrete-Filled Steel Tubular (CFSTS) columns subjected to axial loading. With the growing emphasis on composite construction methods, CFSTS columns have shown superior performance due to their strength, ductility, and efficient material usage. The research evaluates the axial behavior of CFSTS specimens using a combination of experimental testing and finite element modeling. Specimens with varying geometric parameters were tested to observe the impact on load-bearing capacity. Finite Element Analysis (FEA) was conducted using ABAQUS software to simulate the structural response, validate experimental results, and analyze stress distribution. The results demonstrate strong agreement between experimental and numerical outcomes, confirming the accuracy of the model. The study concludes with recommendations for practical application and further research directions in CFSTS structures. This comprehensive investigation contributes significantly to the design optimization and wider adoption of CFSTS columns in civil infrastructure.

Introduction

The construction industry is increasingly adopting composite structural systems for efficient, economical, and sustainable buildings. Concrete-Filled Steel Tubular with Steel (CFSTS) columns, featuring an inner and outer steel tube filled with concrete, offer enhanced load-bearing capacity, ductility, fire resistance, and delayed buckling compared to traditional columns. These columns are especially suited for high-rise, bridges, and seismic structures, with the hollow inner tube reducing weight and allowing space for utilities.

Despite their advantages, research on CFSTS columns under axial loading—particularly considering geometric variations—is limited. This study fills that gap through experiments and finite element simulations to evaluate the axial performance and failure mechanisms of CFSTS columns.

Key points from the study:

• CFSTS columns benefit from dual steel confinement, improving structural stability.

• Experimental specimens varied in tube diameters and wall thickness.

• Testing showed thicker steel walls increased load capacity; larger inner diameters reduced it.

• Failure modes included local buckling and concrete cracking.

• Finite element models validated experiments within a 6% margin.

• Results exceeded Eurocode 4 conservative design predictions by up to 12%.

This work advances understanding of CFSTS columns, offering valuable insights for design and practical applications in modern construction.

Conclusion

The comprehensive experimental and numerical study presented in this paper affirms the significant structural benefits of Concrete-Filled Steel Tubular (CFSTS) columns under axial compressive loads. The results conclusively demonstrate that CFSTS columns possess high axial strength, increased ductility, and favorable energy absorption characteristics, all of which are desirable in modern civil infrastructure applications. The experimental phase confirmed that specimen performance is strongly influenced by geometric parameters, particularly the wall thickness of steel tubes and the spacing between the inner and outer skins. The best-performing columns combined thick steel walls and moderate annular concrete thickness, creating optimal confinement and load-sharing conditions. Observed failure modes, including outward buckling and concrete crushing, aligned with well-documented composite behavior, reinforcing the reliability of the test setup. Finite Element Analysis using ABAQUS proved highly effective in simulating the behavior of CFSTS columns. The model accurately captured load-displacement responses, stress distributions, and failure modes, offering a valuable tool for design validation and parametric studies. Its predictive capabilities allow engineers to simulate a range of configurations without extensive physical testing, significantly reducing cost and time. From a practical standpoint, the CFSTS column system is well-suited for structures requiring high axial load resistance and ductility, such as high-rise cores, bridge piers, and industrial columns. Their hollow core offers opportunities for utility routing or even prestressing tendons in hybrid systems. The improved fire performance due to the concrete infill and dual steel layers adds another dimension of safety.

References

[1] Han, L.H. (2003). Influence of concrete compaction on the strength of concrete-filled steel RHS columns. Journal of Constructional Steel Research. [2] Hassanein, M.F., Patel, V.I., El Hadidy, A.M., Al Abadi, H., & Elchalakani, M. (2018). Structural behaviour and design of elliptical high-strength concrete-filled steel tubular short compression members. Engineering Structures. [3] Dai, X.H., Lam, D., Jamaluddin, N., & Ye, J. (2014). Numerical analysis of slender elliptical concrete filled columns under axial compression. Thin-Walled Structures. [4] Heidarpour, A., & Zhao, X.L. (2017). Tubular Structures XVI. CRC Press. [5] Garbatov, Y., & Soares, C.G. (2025). Innovation in the Analysis and Design of Marine Structures. CRC Press. [6] Aamir Hassan & Javed Ahmad Bhat. (2023). Behavior of partial-length stiffened and full-length stiffened CFSTS columns under axial load. World Journal of Engineering. [7] Al-Kabasi, A.A.A. (2025). Numerical Modelling on the Behaviour of Concrete Filled Steel Tube with Ferrochrome Slag as a Fine Aggregate. Sultan Qaboos University.

Copyright

Copyright © 2025 Ravi Dabas, Ankit Sethi. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.