Title:
Variable Prestress Force in Unbonded Post-Tensioned Members
Author(s):
Kenneth B. Bondy
Publication:
Concrete International
Volume:
14
Issue:
1
Appears on pages(s):
27-33
Keywords:
friction; post-tensioned concrete; prestressed concrete; prestress loss; structural analysis; structural design; unbonded prestressing; Design
DOI:
Date:
1/1/1992
Abstract:
Recent research suggests that redistribution of unbonded tendon force after stressing does not occur in post-tensioned members, contradicting a long-standing assumption that the tendon force becomes constant throughout its length with time. This research recommends that the design of unbonded members should be based upon a variable force along the tendon length, considering initial stressing friction. The ramifications of a variable tendon force approach is discussed and the design of a typical three-span post-tensioned beam using both constant and variable force methods is presented.