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Steel and Composite Structures
  Volume 39, Number 5, June10 2021 , pages 529-542
DOI: https://doi.org/10.12989/scs.2021.39.5.529
 


Experimental and numerical studies on the shear connectors in steel-concrete composite beams at fire and post fire exposures
Olivia Mirza, Sukanta Kumer Shill, M.G. Rashed and Kathryn Wilkins

 
Abstract
    Shear connectors are required to build composite (concrete and steel) beams. They are placed at the interface of concrete and steel to transfer shear and normal forces between two structural components. Such composite beams are sensitive to provide structural integrity when exposed to fire as they loss strength, stiffness, and ductility at elevated temperature. The present study is designed to investigate the shear resistance and the failure modes of the headed stud shear connectors at fire exposure and post-fire exposure. The study includes ordinary concrete and concrete with carbon nanotubes (CNTs) to build composite (concrete-steel) beams with structural steel. Experimental push tests were conducted on composite beams at ambient and elevated temperatures, such as 200, 400 & 600C. Moreover, push tests were performed on the composite beams after being exposed to 200, 400 & 600C. Push test results illustrated the reduction of ultimate shear capacity and stiffness of headed stud shear connectors as the temperature increased. Although similar values of ultimate shear were obtained for the headed stud connectors in both ordinary and CNT concrete, the CNT modified concrete reduced the concrete spalling and cracking compared to ordinary concrete and was observed to be effective at temperatures greater than 400C. All specimens showed a lower shear resistance at fire exposures compared to the corresponding post-fire exposures. Moreover, numerical simulation by Finite Element (FE) analyses were carried out at ambient temperature and at fire conditions. The FE analysis results show a good agreement with the experimental results. In the experimental studies, failure of all specimens occurred due to shear failure of headed stud, which was later validated by FE analyses using ABAQUS.
 
Key Words
    shear; stud connector; steel concrete composite; push test; fire exposure; elevated temperatures
 
Address
Olivia Mirza and Kathryn Wilkins: School of Computing, Engineering & Mathematics, University of Western Sydney (UWS), Australia
Sukanta Kumer Shill: School of Engineering and Information Technology, the University of New South Wales, Australia;
School of engineering, Deakin University, Waurn ponds, Geelong VIC-3216, Australia
M.G. Rashed: School of Engineering and Information Technology, the University of New South Wales, Australia
 

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