the experimental. The theoretical curves predicted rupture of the CFRP longitudinal

reinforcement at the peak load. The predicted peak load was in agreement with the

experimental peak load. Since the theoretical curves were similar to the experimental the

experimental curves were used in the static nonlinear analysis. Both pile bents using the

spun cast piles with and without the CFRP grid showed no significant ductility. Both

load-displacement curves were linear except very closed to peak load were a small

nonlinearity in the curves can be observed.

 80
 70 -A- Low
 70 -Medium
 60 -X-High
 SCG
 S50 SCC
 40
 S30
 20
 100

 0 5 10 15 20 25
 Pile Bent Displacement (in)


Figure 7-7. Load-displacement curves of prestressed pile bents and pile bents using spun
 cast piles reinforced with CFRP bars and grid

 Figures 7-5 through 7-7 show a comparison of the behavior of corrosion damaged

piles from the St. George Island causeway bridge. Piles reinforced or prestressed with

steel will eventually deteriorate due to corrosion, which changes their behavior

significantly over the life of the structure. This is illustrated in each figure by the curves

denoted as low, medium, and high (previously described). The results of the tests on steel

reinforced piles indicate that the capacity deteriorates significantly over time. Yet the

ductility of highly corroded piles appears to be higher than that of uncorroded piles. Even

though highly corroded piles appear to have improved ductility, they also have a