Partial Prestressing Ratio
Partial Prestressing Ratio
AASHTO LRFD Bridge Design Specifications SI units 4th Edition 2007에서
C5.9.5.3에 다음과 같은 내용이 있다.
The approximate lump sum estimates of timedependent prestress losses given in Table 1 reflect values and trends obtained from a computerized timestep analysis of a large number of bridges and building members designed for a common range of variables, namely:
Ultimate concrete creep coefficient ranging from 1.6 to 2.4,
Ultimate concrete shrinkage coefficient ranging from 0.0004 to 0.0006 (mm/mm),
Relative humidity ranging from 40 to 100 percent,
Moist-curing or steam-curing of concrete, and
A PPR ranging from 0.2 to 1.0.
아래 PCI논문을 보면 PPR에 대한 내용이 나온다.
PPR=Aps fpy / ( Aps fpy + As fy )
https://www.pci.org/PCI_Docs/Publications/PCI%20Journal/1993/May/Prestress%20Losses%20in%20Partially%20Prestressed%20High%20Strength%20Concrete%20Beams.pdf
Prestress Losses in Partially Prestressed High Strength Concrete Beams.pdf
Time-Dependent Losses in MPa.
