Floor vibration control system using Macro Fiber Composites

Macro Fiber Composite (MFC) have been recently developed as actuators or sensors. MFC is sheeted piezoelectric devices constructed with fibrous piezoceramics that can produce relatively higher forces than other sheeted piezoelectric devices. The light and flexible device is expected to create many innovative methods for the vibration control of structures. In this paper, we discuss the active control of vertical micro-vibration of floor in buildings using MFCs. We arranged MFCs at the lower flange of both ends of a beam as actuators. By the expansion and contraction of the MFC actuators, bending moments act at both ends of the beam. The synchronized movements of the MFC actuators control the vertical vibration of slab. An experiment of vertical vibration control on a scaled frame model was conducted and the results showed that the control method effectively minimizes the resonant vibration. A vertical vibration control test on a real architectural structure was also conducted. Consequently, the vertical floor vibration of 0.04 m/s2 at 8.5 Hz at the center of the grid was reduced to 0.01 m/s2 or about -12 dB. Moreover, we installed the vibration control system in a real office building in service experimentally. And the examination demonstrated that the system is useful and effective. The workability of arranging MFCs was good, and the installation was completed in two days of office holidays. The floor vibration in office was reduced to 1/3 of that before the installation of the system.