Title:
Tests of Corroded Unbonded Seven-Wire Tendons with Broken Wires
Author(s):
Colin MacDougall and F. Michael Bartlett
Publication:
Structural Journal
Volume:
99
Issue:
6
Appears on pages(s):
803-810
Keywords:
corrosion; deterioration; unbonded tendon
DOI:
10.14359/12345
Date:
11/1/2002
Abstract:
Results of tests on six 13 mm-diameter monostrand tendons, each subjected to one of three aggressive treatments to accelerate corrosion and with one or two broken outer wires, are presented. The remaining prestress fractions and wire strain distributions, when compared with data from tests of uncorroded 13 mm tendons with identical geometric and mechanical properties, indicates that the behavior of the unbonded seven-wire tendons with broken wires is significantly affected by corrosion. Generally, the load-elongation response of the corroded tendons approaches that of an uncorroded tendon with no broken wires. The corrosion product can increase the coefficient of apparent interwire friction, maintain sufficient force in the tendon to mask tendon or wire breaks, and reduce the accuracy of the screwdriver penetration test. The region of low broken wire strain, where the wire break is most likely to be detected by the screwdriver penetration test, can be as short as 1.2 m on each side of the break. The apparent coefficient of interwire friction estimated for heavily corroded tendons suggests that mechanical interlock between the broken and unbroken wires may occur.