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M. Reiterer, F. Ziegler:
"COMBINED SEISMIC ACTIVATION OF A SDOF-BUILDING WITH A PASSIVE TLCD ATTACHED";
Poster: 13th World Conference on Earthquake Engineering (13 WCEE), Vancouver, Canada (invited); 2004-08-01 - 2004-08-06.

One of the effective means of reducing the vibration amplitude of tall buildings, due to horizontal seismic activation, is the installation of tuned liquid column dampers (TLCDs). TLCDs are innovative vibration absorbing devices in the low frequency range, which have been studied extensively in the last decade. However, most research work concentrates on the suppression of horizontal motions of structures, but the vertical component of the seismic activation influences more or less the damping characteristics of an attached TLCD, apparently including the possibility of occurrence of dangerous parametric resonance, likewise to the pendulum type TMD. A detailed study of an SDOF-building with a TLCD attached, under combined horizontal and vertical excitation, is presented in the form of computer modeling and verified with an experimental model setup. The experimental results turns out to be in good agreement with the theoretical predictions of the computer model and both, theoretical and experimental investigations indicate that the vertical component of seismic activation should be considered carefully since in case of parametric resonance the TLCD dynamics would become unstable. However, it will be shown that sufficient damping of the fluid motion is crucial for stability and the optimally required damping coefficient usually turns out to keep the attached TLCD on the safe side. The over-linear turbulent damping presented in the TLCD stabilizes further and contributes one more feature of superiority over conventional TMDs.