Title:
Concrete Creep and Shrinkage and Wire Relaxation in Buried Prestressed Concrete Pipe
Author(s):
Mehdi Zarghamee, Frank J. Heger, and William R. Dana
Publication:
Structural Journal
Volume:
87
Issue:
5
Appears on pages(s):
512-522
Keywords:
concrete pipes; creep properties; prestressed concrete; prestressing steels; prestress loss; relaxation (mechanics); shrinkage; stress relaxation; structural analysis; structural design; Design
DOI:
10.14359/3064
Date:
9/1/1990
Abstract:
A design procedure is presented to compute the prestress losses from creep and shrinkage of concrete and relaxation of the wire for buried prestressed concrete cylinder pipe. The calculation of the creep and shrinkage is based on the recommendations of ACI Committee 209, modified to account for the method of placement of centrifugated concrete and the shrinkage recovery that occurs after burial. Wire relaxation is computed using the measured intrinsic relaxation of the wire and accounting for the effects of creep and shrinkage studies. A Monte Carlo analysis shows that the computed prestresses are not sensitive to the expected variations of the winding forces and of the geometric and material properties. The results are compared with the current industry practice for calculating prestress and test results.