Structural Engineering and Mechanics

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Experimental shear strengthening of GFRC beams without stirrups using innovative techniques

  • Hany, Marwa (Department of Civil Engineering, Benha Faculty of Engineering, Benha University) ;
  • Makhlouf, Mohamed H. (Department of Civil Engineering, Benha Faculty of Engineering, Benha University) ;
  • Ismail, Gamal (Department of Civil Engineering, Benha Faculty of Engineering, Benha University) ;
  • Debaiky, Ahmed S. (Department of Civil Engineering, Benha Faculty of Engineering, Benha University)
  • Received : 2021.10.13
  • Accepted : 2022.05.22
  • Published : 2022.08.25
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Abstract

Eighteen (18) (120×300×2200 mm) beams were prepared and tested to evaluate the shear strength of Glass Fiber Reinforced Concrete (GFRC) beams with no shear reinforcement, and evaluate the effectiveness of various innovative strengthening systems to increase the shear capacity of the GFRC beams. The test variables are the amount of discrete glass fiber (0.0, 0.6, and 1.2% by volume of concrete) and the type of longitudinal reinforcement bars (steel or GFRP), the strengthening systems (externally bonded (EB) sheet, side near-surface mounted (SNSM) bars, or the two together), strengthening material (GFRP or steel) links, different configurations of NSM GFRP bars (side bonded links, full wrapped stirrups, side C-shaped stirrups, and side bent bars), link spacing, link inclination angle, and the number of bent bars. The experimental results showed that adding the discrete glass fiber to the concrete by 0.6%, and 1.2% enhanced the shear strength by 18.5% and 28%, respectively in addition to enhancing the ductility. The results testified the efficiency of different strengthening systems, where it is enhanced the shear capacity by a ratio of 28.4% to 120%, and that is a significant improvement. Providing SNSM bent bars with strips as a new strengthening technique exhibited better shear performance in terms of crack propagation, and improved shear capacity and ductility compared to other strengthening techniques. Based on the experimental shear behavior, an analytical study, which allows the estimation of the shear capacity of the strengthened beams, was proposed, the results of the experimental and analytical study were comparable by a ratio of 0.91 to 1.15.

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References

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