Vibration control of super-tall buildings using combination of tapering method and TMD system

Abstract

Modern super-tall buildings are highly sensitive to wind-induced vibrations due to their high flexibility and low inherent damping. Tapering the cross-section of buildings is an aerodynamic modification to control wind-induced vibrations. Tuned mass damper (TMD) is another control system to mitigate structural vibrations. In the present study, the effect of using the tapering method together with the TMD system on the wind-induced vibration control of super-tall buildings is investigated. A numerical example of super-tall buildings is presented, and the wind-induced responses are computed for four different conditions, including: tapered and non-tapered super-tall buildings with and without TMD system. The along-wind and crosswind responses are computed using the frequency domain analysis for different values of taper and TMD mass ratio. The results indicate that for tapered buildings, the natural frequency of the structure increases as taper ratio increases and since the acceleration is proportional to the square of the natural frequency, tapering method cannot effectively reduce the acceleration response. TMD has higher acceleration control performance than the displacement. By using the two control strategies together, both the displacement and acceleration responses can be effectively suppressed, and this method would be helpful in satisfying the occupant comfort and safety criteria of super-tall building.