Study of Flexural Behavior of High Strength Concrete Beams Reinforced with GFRP Bars

This paper presents the test results of an experimental program which consisted of 8 beams with 100 x 200 mm cross-sectional dimensions.  The beams were tested under four-point loading with an effective span length of 1665mm. Of the eight beams, four beams were reinforced with  GFRP bars and the remaining four beams were reinforced with steel bars. The load-deflection behavior of the high-strength concrete beams reinforced with GFRP bars showed a bi-linear response, while the beams reinforced with steel bars displayed a tri-linear response. The increase in the longitudinal reinforcement ratio and concrete strength resulted in the improvement of flexural capacity, stiffness and ductility of the beams. Frequent drops in the loading were observed in GFRP RC beams while no drops were observed in the case of steel-reinforced beams. This can be attributed to the weak bond of GFRP bars to concrete. Additionally, the layered sectional analysis program, Response-2000, was used to simulate the behavior of the beams, and the ratios of predicted to experimental peak load values were found to be varying from 0.90 to 0.95.