Creep of fiber reinforced polymer (FRP) pile materials.

摘要

Deterioration of conventional piling systems costs the United States nearly ;In this research compressive creep of FRP is addressed. Creep has been modeled by implementing two available methods (thermal and energy), and the models are validated with conventional creep test results for virgin High Density Polyethylene (HDPE). Next, these models are used to estimate the creep of recycled HDPE and E-Glass which are the main components of FRP. By combining the results obtained from these models the creep and ultimate long-term loading capacity of each component and FRP is defined.;Results obtained from both energy and thermal models are in good harmony with each other and with the semi-long-term conventional creep results. The energy method can be adapted to calculate the stress level that would cause the onset of tertiary creep in a given number of years. Ultimate long-term loading capacity for recycled HDPE to prevent tertiary creep in 100 years (the life cycle of polymeric pile) is 1400 psi which is approximately 50% less than the ultimate short-term loading capacity. Similarly, the ultimate long-term loading capacity is close to 13000 psi for E-Glass which again is much lower that E-glass's short-term loading capacity of 22000 psi.;By combining the results and estimating the creep for FRP piling system, it is noted that the ultimate long-term loading capacity for these piles varies from 1600 to 2400 psi based on the E-glass content of the FRP. Introducing a factor of safety of 2 with respect to the variation of the recycled material's quality and nature of geotechnical projects; the allowable loading capacity for this piling system is 800 to 1200 psi. For this stress level the strain over 100 years is less than 1% which is within the acceptable range for geotechnical applications.