EARTHQUAKE VIBRATION CONTROL USING SLOSHING LIQUID DAMPERS IN BUILDING STRUCTURES

Sloshing liquid dampers (SLDs), popularly known as tuned liquid dampers, are used as passive control devices for reducing structural vibrations resulting from wind and earthquake excitations in tall buildings and high-rise structures. Available research studies on these dampers mostly deal with single-degree-of-freedom (SDOF) structures although tall buildings and high-rise structures are generally multi-degree-of-freedom (MDOF) structures. In the present investigation, effectiveness of these SLDs has been studied for MDOF building structures. Five-storied shear buildings have been considered as representative of MDOF structures. It is shown that the liquid sloshing is the most important design parameter, rather than tuning of the fundamental sloshing frequency to the structure frequency, for the liquid damper to be effective. Furthermore, the liquid damper design for multistory buildings is different from that for SDOF structures, where not only the optimal tuning ratio of the liquid damper is different, but multiple dampers located at critical locations are required for effective control of floor accelerations. Finally, it is illustrated that SLDs, if appropriately designed, can be very effective in reducing overall force, floor acceleration, and deformation responses of MDOF building structures for broad-band earthquake type base excitations.