Fire behavior of Concrete Beams Reinforced with Various Combinations of GFRP and Steel

This paper investigates the effects of key parameters on the fire resistance of concrete beams reinforced with various combinations of glass fiber-reinforced polymer (GFRP) and steel. The ratio of GFRP area (Af) to the total area (A) of GFRP and steel varied from 0 to 1, making steel, hybrid GFRP-steel, and GFRP-reinforced concrete (RC) beams. Finite element models of these beams were developed in SAFIR software and verified. The models were then used to analyze the effects of different key parameters on the fire behavior and fire resistance of these beams. The results demonstrated that the fire behavior of these beams was significantly affected by the Af/A ratio, load ratio, total reinforcement ratio, and concrete cover thickness, while it was marginally affected by steel and concrete strengths. The fire resistance decreased with the increases in load ratio and Af/A ratio, whereas it increased with the increases in concrete cover thickness or reinforcement ratio. Fire resistance slightly increased with the increase in the tensile strength of steel and slightly decreased with the increase in the compressive strength of concrete. The location arrangement of GFRP and steel bars in cross sections significantly affected the fire behavior and fire resistance of hybrid beams. The deflection rate limit, rather than the deflection limit, decisively governed the fire resistance of concrete beams reinforced with different Af/Aratios. Regression analyses yielded models for estimating the fire resistance. Doi: 10.28991/CEJ-2025-011-05-018 Full Text: PDF