Effective damping devices for stay cables under wind load

Abstract

Stay cables, such as are used in cable-stayed bridges, are prone to vibration due to their low inherent damping characteristics. Several methods have been proposed and implemented to mitigate this problem, though each has its limitations. In structural fields, discrete viscous damper have been used on lots of bridges. It has been, however, demonstrated that the damper attachment location should be typically restricted to be within 5% of the cable length from the cable anchorage and passive damper cannot provide supplemental damping with damper location smaller than 2% of the cable length. Recently some studies have shown that active and semiactive control system using MR (Magnetorheological) damper can potentially achieve both higher performance levels than passive control system and adaptability with few of the detractions. However, a control system including a power supply, controller, and sensors is required to maximize the performance of the MR damper and this complicated control system is not effective to most of large civil structures. This study proposed new-type damping devices for vibration of stay cables. Firstly, high-performance damping system can reduce the required capacity of a linear viscous damper without the loss of performance of the damper. This study shows that the efficacy of the proposed damping system has been analytically and experimentally investigated. Secondly, a smart hybrid damping system consists of high-performance damping system and an electromagnetic induction (EMI) system. The smart hybrid damping system can be effective damping device without any external power supply and control algorithm. This study represents analytical verification of the proposed damping system.