Ultimate strength of damaged post-tensioning tendons

In order to assess the influence of the bond action between wires, injection grout and the surrounding concrete on the ultimate load of damaged post-tensioning tendons more accurately, a series of tensile tests on tendons, which were built using old wires from a demolished bridge, was carried out. Wire breakage was included in the tendons at specified patterns. The results of the test series show that tendons with damaged or broken wires are able to carry a very high percentage of the ultimate load of an undamaged tendon. Even in situations where no confinement of stirrups in the surrounding concrete is present, the load-carrying capacity of tendons with broken wires is excellent. If the distance between the wire breakages is about half the anchorage length, the decrease in strength is about 20%. The results of these tests will be used to assess the tendon strength in comparable bridge structures where damage to the tendon is likely to be present.