Experimental and numerical investigation on the flexural response of GFRP ‐reinforced SFRC beams

Abstract

In order to address the challenges related to the deformability and ductility of concrete beams reinforced with fiber reinforced polymer (FRP) bars, an alternative solution involving steel fiber reinforced concrete (SFRC) has been proposed. In the present study, a total of seven beams—including one steel‐reinforced reference beam and six glass FRP (GFRP)‐reinforced beams—were tested under four‐point bending. The influence of varying steel fiber content (0%, 0.5%, 1%, and 1.5%) and GFRP reinforcement ratio ( ρ _f  = 0.85%–1.71%) on the structural performance of concrete beams reinforced with GFRP bars was studied. The tested beams were analyzed in terms of deflection, crack width, load‐carrying capacity, and failure mode. The test results indicated that the addition of steel fibers notably reduced deflection and crack width in GFRP‐reinforced concrete (RC) beams. Specifically, increasing the steel fiber content from 0% to 1.5% resulted in an approximately 40.70% reduction in maximum crack width. Similarly, increasing ρ _f from 0.85% to 1.71% led to an 86.60% decrease in mid‐span deflection. Furthermore, increasing ρ _f resulted in higher flexural capacity, smaller crack widths, and higher post‐cracking stiffness. This study also proposes a refined compatibility‐based computational approach based on force equilibrium and strain compatibility principles to assess the moment–curvature ( M – φ ) response, flexural capacity, and deflection behavior of SFRC beams reinforced with GFRP bars, which was validated against both the experimental results of this study and an extensive database from the literature, addressing the limitations of existing ACI‐based approaches. The moment capacity estimates derived from this method agree well with both the experimental findings of the current study and data reported for 38 FRP‐RC beams in the available literature.