Adaptive Passive Negative Stiffness and Damping for Retrofit of Existing Tall Buildings with Tuned Mass Damper: TMD-NSD

It is known that the performance of traditional passive tuned mass dampers (TMDs) is highly sensitive to vibration frequency. The fundamental frequency of existing tall buildings may shift to lower value due to damage or other reasons. In this regard, this paper deals with the resultant detuning problems of a traditional passive TMD for vibration control by retrofitting it with a passive adaptive negative stiffness device (NSD). The applied NSD not only provides negative stiffness for adjusting the TMD's de-tuned stiffness at its working stage, but also offers a fail-safe limiting stop for the TMD at large deformation/stroke. In this study, compared to the original TMD, a novel TMD-NSD assembly is proposed that is shown to be more effective for serviced structures. For example, the original TMD can only provide about 2.83% additional damping ratio to frequency-changed structures, while the newly proposed TMD-NSD further improves the damping ratio to 5.34%. Moreover, in the study it is found that the TMD-NSD also outperforms the TMD in resisting dynamic lateral loading such as along winds, cross winds, and earthquakes.