COMPOSITE MASS DAMPERS FOR VIBRATION CONTROL OF WIND-EXCITED TOWERS

Various systems for controlling the vibrations of tall buildings subje cted to earthquakes or strong winds have been developed and applied ov er the past few years. This paper is concerned with the use of a compo site active-passive tuned mass damper (APTMD) system for the vibration control of a single-degree-of-freedom tower under the along-wind and the across-wind excitations, respectively. The effectiveness of this r elatively new composite tuned mass damper system is investigated and c ompared with the more well-known active tuned mass damper system. The results show reductions in the wind-induced displacement responses of the towers are greater with APTMD if the appropriate damper and contro l parameters are selected. More importantly, these better performances may be achieved with a relatively smaller mass for the active part of the control. Such a smaller active damper mass is advantageous for in stallation purposes. The parametric studies conducted herein also show that the APTMD system is not so sensitive to the small variations of the structure-damper mass ratio, the frequency ratio and damping facto r of the damper. These APTMD characteristics are useful in design. (C) 1998 Academic Press Limited.