Behavior of CFRP confined rectangular high-strength concrete-filled steel tubular columns under eccentric compression

• Published in: Engineering structures 2024-12, Vol.321, p.119006, Article 119006
• Main Authors: Gao, Dinghui, Du, Yansheng, Chen, Zhihua, Zhao, BingZhen
• Format: Article
• Language: English
• Subjects: Carbon fiber reinforced polymer (CFRP); Eccentric compression behavior; Fiber element method; High-strength materials; Rectangular concrete-filled steel tube
• ISSN: 0141-0296
• DOI: 10.1016/j.engstruct.2024.119006

This paper presents an experimental study on the eccentric compression behavior of rectangular high-strength concrete-filled steel tubular columns confined with carbon fiber reinforced polymer (CFRP- CFST). Seventeen specimens were tested under eccentric compression, examining key parameters involving eccentricity, number of transverse CFRP layers, slenderness ratio, corner radius, CFRP partial wrapping scheme, and CFRP orientation. The effects of these parameters on failure mode, load-displacement relationship, strain development, and ultimate mechanical properties were analyzed and discussed. The ultimate bearing capacity (Nu) of CFRP-CFST columns improved with an increase in transverse CFRP layers, corner radius, and CFRP wrapping proportion, while it decreased with increasing eccentricity and slenderness ratio. Partial wrapping schemes reduced the effectiveness of CFRP confinement, with the outward local buckling of the steel tube primarily occurring in areas without CFRP confinement. Longitudinal CFRP provided less improvement to Nu compared to transverse CFRP under small eccentricity conditions. A theoretical model based on the fiber element method was developed to predict the ultimate bearing capacity and implemented through a custom program to facilitate calculations. The model was validated using a test database comprising results from this study and previous research. Additionally, axial force-bending moment (N-M) interaction curves were rapidly generated, providing a theoretical basis for the design and practical application of CFRP-CFST columns in practical engineering.