Semiactive control of stay cable vibration using MR dampers

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 the cable vibration, though each has its limitations. Recently some studies have shown that semiactive dampers can potentially achieve performance levels nearly the same as comparable active devices with few of the detractions. This thesis presents the results of a study to evaluate the performance of semiactive dampers for mitigating the vibration of stay cables in analytical and experimental ways. In analytical study on semiactive cable vibration control, four recently proposed semiactive control algorithms are formulated for use with shear mode MR damper and the performances of each semiactive damping systems are compared with passive control systems and the other semiactive control systems. In experimental study on semiactive cable vibration control, the full-scale stay cable, which is the same as used for the in-service cable-stayed bridge in Korea, is considered. Semiactive control system which consists of digital controller, experimental sensors, and MR dampers is established. The performances of the several control strategies for the semiactive control system have been compared with those of the passive-type control systems employing MR dampers.