Techno Press
Techno Press

Steel and Composite Structures
  Volume 57, Number 5, December 10 2025 , pages 421-439
DOI: https://doi.org/10.12989/scs.2025.57.5.421
 


Experimental and analytical investigation of square concrete-filled stiffened steel tubular stub columns with ring stirrups
Tarek Sharaf, Ahmed Hanefa, Mohamed Dabaon, Mohamed ElGhandour and Ashraf ElSabbagh

 
Abstract
    This paper presents an experimental, numerical, and analytical investigations into the behavior of square concrete filled cold formed stiffened steel tubular stub columns with ring (hoop) stirrups (SC-CFSST) under axial compression. The proposed composite column is fabricated by cold-bending four plates to form four parts of lipped angles, which are assembled by argon welding. Ring stirrups are inserted through the perforations along the longitudinal lips to provide additional confinement. To explore the combined enhancement effects of stirrups and stiffeners, six SC-CFSSTs confined with stirrups and three concrete-filled stiffened steel tubular (CFSST) stub columns without stirrups were tested. Experimental procedures, and results are discussed in detail. A finite element (FE) model was developed to simulate the models of specimens and validated against experimental results. The validated model was employed to conduct a parametric study to better understand the behavior of SC-CFSST columns with different parameters. The results demonstrate that installing ring stirrups significantly enhances confinement effect, improving both ultimate strength and enhances post-peak performance. In addition, international design provisions were utilized to predict the ultimate axial load of CFSSTs and SC-CFSSTs. The results were compared with experimental and numerical results, showing that the DBJ design approach provides the most accurate predictions. A new formula was introduced to estimate the ultimate strength of CFSSTs and SC-CFSSTs, considering combined confinement effects. The formula showed improved accuracy in predicting ultimate strength compared to both FE simulations and existing design predictions.
 
Key Words
     axial compression; cold-formed; concrete-filled; design codes; experimental analysis; FE analysis; stirrups
 
Address
Tarek Sharaf:Department of Civil Engineering, Faculty of Engineering, Port Said University, Port Said, Egypt

Ahmed Hanefa:Department of Civil Engineering, Faculty of Engineering, Port Said University, Port Said, Egypt

Mohamed Dabaon:Department of Civil Engineering, Faculty of Engineering, Tanta University, Tanta, Egypt

Mohamed ElGhandour:Department of Civil Engineering, Faculty of Engineering, Port Said University, Port Said, Egypt

Ashraf ElSabbagh:Department of Civil Engineering, Faculty of Engineering, Port Said University, Port Said, Egypt
 

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