Introduction

Concrete-Filled Steel Tube (CFST) columns are widely utilized in modern structural engineering due to their superior axial load-bearing capacity, ductility, and fire resistance. These composite members synergize the compressive strength of concrete and the confinement effect of the surrounding steel tube, making them highly effective in high-rise buildings and bridge piers.

To further enhance the mechanical performance of CFST columns, particularly under axial compression, innovative hybrid configurations have been investigated. One such configuration involves embedding an inner I-shaped Carbon Fiber Reinforced Polymer (CFRP) profile within the concrete core. CFRP materials are known for their high strength-to-weight ratio, corrosion resistance, and excellent fatigue performance. The inclusion of an I-shaped CFRP profile offers several potential advantages: improved load distribution, enhanced confinement, and delayed local buckling of the steel tube.

Embedding CFRP profiles in CFST columns represents a novel hybrid structural system that can potentially enhance performance under axial loading. The findings of this study could inform the design of more resilient and lightweight composite columns suitable for modern construction demands. Additionally, the use of CFRP can mitigate issues related to steel corrosion and concrete degradation over time, contributing to longer service life and reduced maintenance.

This study focuses on the axial compression behavior of middle-long CFST columns with centrally embedded I-shaped CFRP profiles. The primary objectives are to assess the influence of the CFRP insert on load-carrying capacity, failure modes, and deformation characteristics, and to compare the performance with conventional CFST columns without internal reinforcement. Experimental compression tests are conducted to analyze parameters such as peak load, axial displacement, stiffness degradation, and interaction between the steel tube, concrete core, and CFRP profile. In this example, the dynamic explicit step is selected to perform the simulation.

Understanding the behavior of such hybrid columns under compression not only contributes to improved structural efficiency but also provides insights into novel composite configurations for advanced civil engineering applications.