DEMONSTRATION OF TUNED MASS DAMPER EFFECTIVENESS VIA LONG-TERM STRUCTURAL MONITORING

The wind tunnel study of a super tall and slender skyscraper predicted that occupants may experience motion comfort issues during common wind events. As such, a tuned mass damper (TMD) was designed and installed inside the skyscraper. A structural monitoring system was subsequently installed to continually record bi-axial responses of both the building and the TMD. The monitoring recorded building and TMD accelerations during both ambient (calm) and significant wind conditions, with maximum gust speeds reaching 77 km/hr at the nearby airport. Using the ambient data, the natural frequencies and, to some extent, the inherent damping of the building were identified even with a TMD installed. Under high wind conditions, the approximated total effective damping and the spectral shape of the responses visibly change from the ambient results, indicating that the TMD is functioning as designed. The continuous data recording also captured comparative responses during a series of consecutive events wherein the TMD was briefly locked out one morning while gust speeds reached 56 km/hr. When the TMD was later released on the same morning, the gust speeds reached a comparable 57 km/hr from approximately the same direction. The responses captured were compared with those from when the TMD was locked out, indicating the total effective damping introduced by the TMD, thus demonstrating its effectiveness.