Passive, Semi-Active, and Active Tuned-Liquid-Column Dampers

Abstract

The dynamic characteristics of the passive, semi-active, and active tuned-liquid-column dampers (or TLCD’s) are studied in this paper. The design of the latter two are based on the first one. The water-head difference of a passive TLCD is pre-set to form the so-called semi-active one in this paper. The water-head difference is released at a proper time instant during an earthquake excitation to enhance the vibration reduction of a structure. Two propellers are installed along a shaft inside and at the center of a passive TLCD to form an active one. These two propellers are driven by a servomotor controlled by a computer to provide the control force. The seismic responses of a five-story shear building with a passive, semi-active, or active TLCD are computed for demonstration and discussion. The results of this building with a tuned mass damper (or TMD) are also included for comparison.