BOND OF HOOKED GLASS FIBER REINFORCED PLASTIC (GFRP) REINFORCING BARS TO CONCRETE

Abstract

The objective of this study was to examine the bond behavior of hooked glass fiber reinforced plastic (GFRP) reinforcing bars to concrete. Thirty-six 90-deg hooked reinforcing bar specimens were tested to determine the effects of concrete compressive strength, radius of bend, tail length, straight embedment length, and reinforcing bar diameter under monotonic static loading. The slip between the reinforcing bars and concrete was measured at the loaded end for various load levels. The tensile load was applied to the reinforcing bar until splitting of concrete or fracture of reinforcing bar occurred. The test results revealed that, with increases in concrete compressive strength, radius of bend, and straight embedment length, the ultimate tensile stress and initial stiffness increased and the maximum slip at failure decreased. The tail length beyond 12 bar diameters had little effect on the ultimate tensile stress. Based on a regression analysis of the test results, investigators recommend that the development length of hooked GFRP bars be taken as 16 times the bar diameter.