Bond of glass-fiber-reinforced-plastic reinforcing bars to concrete.

Abstract

The objective of this research project was to study the bond behavior of Glass-Fiber-Reinforced-Plastic (GFRP) reinforcing bars (rebars) to concrete. A total of 102 specimens were experimentally investigated and theoretically analyzed at The University of Arizona. The static tensile load was applied to the rebars in a gradual increment of load level until splitting of concrete, rebar pull out failure, or rebar fracture occurred. The slip between the rebars and concrete was measured at the loaded and free ends at each load level. Variables included in the specimens were concrete compressive strength, embedment length, clear concrete cover, rebar diameter, concrete cast depth, radius of bend, tail length, and lead embedment length. On the basis of the experimental results, the study showed that concrete compressive strength, embedment length, clear concrete cover, concrete cast depth, and radius of bend had significant effects on bond of GFRP rebars to concrete. New criteria for acceptable bond performance of GFRP rebars to concrete were established. Furthermore, the practical design guidelines for calculating the development lengths of straight and hooked GFRP rebars to concrete were determined. In addition, confinement factors were also derived to reflect the influence of concrete cover and casting position.