Flexural Behavior and Serviceability of Normal- and High-Strength Concrete Beams Reinforced with Glass Fiber-Reinforced Polymer Bars

Abstract

This paper investigated the flexural behavior and serviceability performance of glass fiber-reinforced polymer (GFRP)-reinforced concrete (GFRP-RC) beams fabricated with normal- and high-strength concretes (NSCs and HSCs). The beam specimens measured 4250 mm long x 200 mm wide x 400 mm deep (167.0 x 8 x 16 in.). Three GFRP products with moduli of elasticity ranging from 48.7 to 69.0 GPa (7100 to 10,000 ksi) with sand-coated and helically grooved surface textures were employed. A total of 12 full-scale beams reinforced with GFRP bars and two reinforced with steel bars, serving as control specimens, were tested to failure in four-point bending over a clear span of 3750 mm (148 in.). The test parameters were: 1) type and ratio of the GFRP reinforcement; 2) surface configuration of the GFRP bars; 3) concrete strength; and 4) bar diameter. The test results were reported in terms of deflection, crack width, strains in concrete and reinforcement, flexural capacity, and mode of failure; they were also employed to assess the accuracy of the current deflection and crack-width prediction equations in the FRP-RC codes. The test results revealed that the crack widths were affected by the bar diameter and surface configuration while the deflections were not significantly affected. In addition, the bond coefficient kb value of 1.4 was very conservative for both of the sand-coated and helically grooved GFRP bars in NSC and HSC.