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Home > Publications > International Concrete Abstracts Portal
The International Concrete Abstracts Portal is an ACI led collaboration with leading technical organizations from within the international concrete industry and offers the most comprehensive collection of published concrete abstracts.
Title: In Situ Measurement of Stress Losses in Unbonded Tendons of Post Tensioned Flat Slabs
Author(s): S. SOARES, J. M. CALIXTO, H. CHUMBINHO
Appears on pages(s): 237-260
Keywords: post-tensioning flat slabs, unbonded tendons, stress losses.
Abstract:This paper presents the results of “in situ” measurements of stress losses in unbonded tendons of post tensioned flat slabs. These flats
slabs have approximately 350 m2 in area and are 17 centimeter thick. They are part of a 16 story high hotel building. Load cells were
employed to measure the forces in the tendons; they were placed in the vicinity of the active and the passive anchorages. The forces in
the tendons were monitored from the time of their straining up to 170 days afterwards. The measurements reveal a frictional coefficient
µ equal to 0.0528, a very close value to the one prescribed by NBR 6118 of 0.05. The stress loss due to the anchorage of the tendons
was of 5.17% of the initial stress. The results indicate also that the remaining force near the passive anchorage is larger in relation to
the value measured in the vicinity of the active one. The total stress loss measured so far (170 days) corresponds to 14 % of the initial
Brazilian Institute of concrete, International Partner Access.
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