A variable gain state‐feedback technique for an AMD control system with stroke limit and its application to a high‐rise building

As the auxiliary mass of an active mass damper/driver (AMD) control system in a high‐rise building has excessive strokes and its relative velocities are in the same direction with the strokes, the auxiliary mass probably collides with its anti‐collision device. As a result, the structural responses increase and even the structural safety is endangered. In this paper, a variable gain state‐feedback control system is proposed to limit the strokes and relative velocities of the auxiliary mass, so as to ensure the safety of the system. Firstly, the limited state of the auxiliary mass is defined, and a regional pole assignment algorithm that utilizes only a damping factor is realized as a control gain. Then the relationship between the control gain corresponding to the stroke and its threshold limit value is deduced. A suitable threshold limit value is chosen to reduce the strokes and the relative velocities. Finally, the performance characteristics of the control systems with or without stroke limit are analyzed. The results demonstrate that the controller limits the strokes effectively on the premise of guaranteeing the control effects and the AMD parameters. To verify its effectiveness, the proposed methodology is also applied to an experiment of a four‐storey frame.     

Effects of tuned mass damper on correlation of wind‐induced responses and combination coefficients of equivalent static wind loads of high‐rise buildings

Tuned mass dampers (TMDs) are employed to control the wind‐induced responses of tall buildings. In the meantime, TMD may have an impact on the correlation of wind‐induced responses and combination coefficients of equivalent static wind loads (ESWLs). First, the mass matrix and stiffness matrix were extracted in this paper in accordance with the structural analysis model of two high‐rise buildings, and on that basis, the wind‐induced vibration responses analysis model with and without TMD was established. Second, the synchronous multipoint wind tunnel test to measure the pressure was performed for two high‐rise buildings, and the time history of wind‐induced vibration responses with and without TMD was studied. Finally, the impact of TMD on the correlation of wind‐induced responses and combination coefficients of ESWLs was discussed. The results of two examples suggest that after the installation of TMD, the increase of ρ_xy was 2.1% to 35.0% and ρ_yz was 2.8% to 45.6% at all wind directions for Building 1, and the increase of ρ_xy was 3.9% to 17.1% and ρ_yz was 6.8% to 38.3% for Building 2. The combination coefficients of ESWLs of two buildings were 3% to 6% larger than that of the original structure. The conclusion of this paper can be referenced by the wind resistant design of high‐rise buildings with TMD.