Design, Implementation and Measurement of Cable Dampers for Large Cable-stayed Bridges

This paper will discuss countermeasures used to mitigate cable vibration. Long stay cables are very sensitive to ambient excitations, such as wind, wind-rain or traffic loads, due to their low inherent damping and rich vibration modes. The vibration of stay cables on existing bridges are frequently observed and vibration control countermeasures have to be considered for the cables. The vibration control countermeasures usually adopted are aerodynamic means, cable cross ties and mechanical dampers. This paper focuses on the performance study of the vibration mitigation countermeasure for stay cables using mechanical dampers which are usually passive or semi-active dampers installed near the anchorages of cables in transversal direction and are effective for all kinds of vibrations. This paper carries out experimental studies on damper performance and additional cable damping with tests conducted using a 215 meter long full-scale stay cable. The reasons causing the damping loss, namely, the deference between the theoretical and the measured damping are discussed. Improved design methods were proposed and the cable damping of a large span cable-stayed bridge was measured.