Structural response of high strength concrete beams using fiber reinforced polymers under reversed cyclic loading
  • Mohamed T. Elshazli, Nick Saras, Ahmed Ibrahim*
Sustainable Structures   Vol.2,No.2,2022  DOI:10.54113/j.sust.2022.000018  Online published:2022-12-1
This paper investigates the response of high strength concrete (HSC) beams subjected to reversed cyclic loading using carbon fiber-reinforced polymer (CFRP), glass fiber-reinforced polymers (GFRP), and hybrid FRP/steel bars as bottom tensile reinforcement. Five HSC beams with a rectangular cross-section were prepared and cast using concrete with a 28-day compressive strength of 60 MPa (8.7 ksi). A displacement-controlled reversed cyclic loading has been applied to all the beams. The test setup has been designed to simulate the forces and boundary conditions that could happen during seismic action. Flexural capacity, concrete and reinforcement steel strains, cracking behavior, and ductility results were obtained. The hybrid steel/FRP has shown an improved performance in terms of flexural capacity, strains, and ductility. While the inclusion of FRP grids reduces the flexural capacity, this can be improved by adding more layers of FRP. The hybrid reinforced sections showed an increase in moment capacity and ductility compared to the FRP only reinforced beams. The mechanistic model predicted values using code ACI 318 and 60% of the given FRP tensile strength were in good agreement with the experimental results. For the hybrid reinforced beams, moment capacities calculated using ACI 440R was shown to be over-estimated. Although ACI 440R designs for externally wrapped FRP, the sectional analysis was performed with the same process as ACI 318.
High strength concrete; carbon fiber; glass fiber; reversed cyclic