| Floor vibration has become a serious structural problem for the occupants of some modern buildings. Transient floor vibration due to the normal activities (e.g., walking) of occupants in a typical office building with a steel frame has been investigated in this research. Such floor motion can be excessive and very annoying to occupants. To attenuate this excessive vibration, several remedial vibration-control methods are available (adding framing members, thickening the floor, etc.) but are not easy to implement in existing floors.; One of the most effective, passive vibration-treatment methods for reducing floor vibration is the use of the tuned mass damper. A new design of a tuned mass damper with three degrees of freedom and a unique configuration is proposed in this research; i.e., the three-degree-of-freedom tuned mass damper (3-DOF TMD). Due to its new configuration, the proposed TMD can fit easily into the ceiling cavities of most floor systems. Unlike the typical TMD, which commonly requires a large amount of viscous damping, the 3-DOF TMD needs only a small amount of damping. Thus, the damping can be introduced into the proposed system through viscoelastic damping material.; The main purpose of this work has been to conduct analytical and experimental studies on the use of the 3-DOF TMD to abate floor vibration. In our studies to improve the dynamic behavior of the floor, a single 3-DOF TMD was tuned to the first vibration mode of the floor. For the floor system with this new TMD, the numerical simulation with both MATLAB and ANSYS showed an increase in the first-mode damping ratio from 0.5% to about 7.5%. To verify the effectiveness of the proposed TMD experimentally, a scale model of the floor was designed and constructed. After installing the 3-DOF TMD on the floor scale model, the equivalent damping ratio of the first mode increased from 5.8 to about 12%. The 3-DOF TMD proved analytically and experimentally to be very effective in providing additional damping to the target vibration mode and reducing the floor vibration. |
