Investigation of pullout strength of pre-installed glass fibre reinforced polymer bars in high-performance concrete

Fibre reinforced polymer (FRP) bars are rapidly becoming an alternative to conventional steel reinforcing bars in bridge construction. This research investigated the bond behaviour of glass fiber reinforced polymer (GFRP) bars embedded in high-­‐performance concrete (HPC). Sand-­‐coated and ribbed-­‐surface GFRP bars of 16 and 20 mm diameters were considered in this study. Concrete blocks were cast with embedded GFPR bars to conducted pullout tests to examine the effect of varying parameters on their pullout and bond strengths, namely: embedment length, bar diameter, surface treatment, and concrete cover. In addition, bond characteristic were analyzed between straight and head-­‐ended sand-­‐coated GFRP bars. The experimental results were used to evaluate the development lengths specified in design codes. It was determined that the development lengths for straight GFRP bars provided by the codes are conservative. Also, the development length for head-­‐end bar is shorter than that for similar bar with straight end.