Vibration Control of Bridge Tower Under Construction Using Active Mass Damper

Abstract

For large structures such as towers of suspension bridges or cable-stayed bridges, we often need to suppress wind-induced vibration for safety. Especially in the construction stage, the structures have a low tolerance than completed ones. This paper discusses the active vibration dampers used to suppress wind-induced vibration of a tower of a suspension bridge during a construction. The active damper was used to suppress wind-induced vibration in multiple modes predicted by wind-tunnel test. The controller design of the dampers is based on H^∞ robust control theory. At each erection step, we measured dynamic properties of towers to adjust parameters of the controller using active vibration exciters. The measured dynamic properties of active controlled structures are compared with those of non-controlled structures. The analysis of free vibration shows the suppression performance of active damper as expected in the controller design.