2022 Volume 3 Issue 2 Pages 2-10
Estimating the tension acting on cables is essential for the maintenance of cable structures such as cable-stayed bridges and extradosed bridges. The safety of a cable can be assessed by comparing the tension acting on the cable and the allowable value. In the current Japanese practice, the tension of a cable is estimated using the vibration or higher-order vibration method, which considers the natural frequencies of the cable. However, recently, the wind-induced aerodynamic vibration of cables has become a problem. In such a case, dampers are installed onto the cables to suppress the aerodynamic vibration. Consequently, the damper changes the cable’s natural frequencies; thus, the vibration and higher-order vibration methods are inappropriate for estimating the tension of a cable with a damper. The authors previously developed a tension estimation method for a cable with a damper, where the cable is modeled using a tensioned Bernoulli-Euler beam. A theoretical equation that relates the natural frequencies of the cable with the tension and bending stiffness of the cable and damper parameters was derived. The method is used to inversely estimate the tension and bending stiffness of the cable and damper parameters simultaneously based on the cable’s natural frequencies. In this study, the tension estimation method is first introduced, then validated using numerical simulations, and subsequently verified via a laboratory experiment. Moreover, field measurements of a cable-stayed bridge in Japan were performed to verify this method. Results show that the tension estimation method can estimate the tension of a cable with a damper with high accuracy, thereby validating the method.
