Development Report:
Vibration Control of Hakucho Bridge Tower under Construction Using Actively-Controlled Mass Damper
Morito Takahashi*, Satoshi Nishimoto**, Koh Hashimoto**,
Yuji Koike***, Masao Mutaguchi**** and Hidesaku Ueshima*****
*Hokkaido Development Bureau, 8, Minami, 4, Nishi, Obihiro, Hokkaido, 080 Japan
**Hokkaido Development Bureau, 1-128, Shukutsu-cho, Muroran, Hokkaido, 051 Japan
***Research Institute, Ishikawajima-Harima Heavy Industries Co., Ltd., 1, Shin-nakahara-cho, Isogo-ku, Yokohama, Kanagawa, 235 Japan
****Steel Structures Division, Ishikawajima-Harima Heavy Industries Co., Ltd., 1-9-10, Mouri, Koto-ku, Tokyo, 135 Japan
*****Bridge Division, Ishikawajima-Harima Heavy Industries Co., Ltd., 1-9-10, Monti, Koto-ku, Tokyo, 135 Japan
Free-standing bridge towers, in general, suffer from vibrations caused by wind. In order to reduce vibrations, an actively-controlled mass damper was applied to Hakucho Bridge tower. In controlling vibrations, the node of the 2nd mode was selected as a settling point of sensors in order to maintain stability for higher order modes of vibration than that to be controlled. The damper was tested to verify damping performance by free vibration and measurement of vibrations caused by wind. High performance has been obtained from results of tests and the effectiveness of this method has been demonstrated.