Active tuned liquid column gas damper in structural control

Abstract

Tuned liquid column gas damper (TLCGD) show excellent vibration absorbing capabilities appropriate for applications in wind- and earthquake engineering. However, in the early regime of strong motion seismic excitation or to counteract strong wind gusts the performance of the passive device can be increased substantially by active elements obtained from adding a pressurized gas supply with input-output valves to the sealed ends of the TLCGD. To prove the working principle of active TLCGD several small scale laboratory experiments have been performed with single and multiple degree of freedom host structures. To obtain a desired dynamic behavior, a conventional feedback control law is used to compute small active pressure inputs to the TLCGD. The experiments have proven that the active device is able to substantially reduce the dynamic system response in a broad frequency range. In fact, dangerous structural resonances of lightly damped structures can be avoided even if the passive absorber is not tuned perfectly. For multiple degree of freedom host structures a suitable control enables a single active TLCGD to counteract several modes of vibrations thereby avoiding the need to install numerous passive devices.