Both specimens had a significant loss of their load bearing capacity due to rupture

of the CFRP grid and subsequently loss of confinement and ruptured GFRP reinforcing

bars (see Fig. 5-14). It is also important to note that the specimens did not collapse but

continued to carry their own weight plus an additional load of approximately 18.8 kips

for specimen 1 and 15.7 kips for specimen 2. Specimen capacity was diminished when

more GFRP bars ruptured.

















Figure 5-14. Ruptured CFRP grid and GFRP reinforcing bar (specimen 2)

 From the tests results for specimens 1 and 2 it can be concluded that ductile

behavior of a pile reinforced with GFRP bars can be achieved by providing confinement

to the concrete. The results further support the conclusion that the CFRP grid can provide

confinement to concrete and therefore improve the ductility of the pile. The plateaus in

Fig. 5-11 were a result of the combine effect of concrete confinement provided by the

CFRP grid as well as the back curve of the GFRP reinforcing bars. However, without the

added concrete ductility due to the CFRP grid confinement the plateaus would not have

been present in the load-displacement curves and failure would have taken place by

crushing of the compression zone at approximately the location where the plateaus begin.