Vibration control of tall buildings using mega subconfiguration

An innovative vibration-control system is proposed to reduce the dynamic response of tall buildings to wind and seismic loads. This system takes advantage of the so-called megasubstructure configuration, which is especially popular in tall buildings. Substructures contained in the megastructure serve as energy absorbers so that no additional mass is required for the intended vibration control as seen in the conventional mass damper systems. The proposed system naturally resolves the difficulties in augmenting damping capacities of tall buildings associated with the high rigidity and deformation in the dominant bending mode. Dynamic characteristics of the proposed control system including the frequency response and the energy flow are investigated. Optimal values of structural parameters such as the damping ratio and stiffness of the substructure are determined. The feasibility and effectiveness of this unique control system in improving human comfort and protecting structures under both wind and earthquake loads are demonstrated through analytical and numerical analysis.