Experimental Evaluation of Vibration Response of External Post-Tensioned Tendons with Corrosion

This study investigates the vibration responses of external post-tensioned (PT) tendons based on experimental data. The vibration signals measured from four large-scale external post-tensioned tendon specimens subjected to localized corrosion until severe level of damage were accumulated. A series of impact tests was conducted to measure lateral vibration signals and the variation in the tension was continuously monitored using a load cell. The acquired vibration signals were evaluated using an axially-tensioned beam model in which the properties were varied to reflect the loss of tension and the reduction in the bending stiffness caused by corrosion damage. A comparison between the experimental data and the analytical results indicates that the natural frequencies were shifted as the residual tension decreased but were influenced by corresponding grout damage in a limited range. As a result, the frequency response was not appreciably affected by the damage level and the tension remained as the primary structural parameter of the external PT tendon with damage.