Vibration Control of Benchmark Building with Single and Multi-storey Stacked TMDs

Tuned mass dampers (TMDs) placed in skyscrapers show huge deflections and accelerations as they absorb a lot of the energy from the main structure. The responses of these TMDs need to be controlled with some additional dampers to keep their motion in check. The current paper deals with the numerical study of a similar system (stacked TMD system) in which a TMD (secondary TMD) is used to control the main TMD (primary TMD), which, in turn, is used to control the structure. Primary TMD is also analogous to important equipment such as a server placed in a building which needs to be controlled. In this study, the response of a 76-storey Benchmark building is investigated under across-wind loads. Dynamic Time History Analysis of the building is performed in MATLAB 2010a using the wind time history data by state-space method. In addition to deflections, drift and acceleration responses are also evaluated. Two systems of primary TMD have been studied. One system consists of conventional TMD, i.e., single mass-stiffness-damping device. The second system consists of three mass-stiffness-damping systems connected in series (i.e., the mathematical model is similar to a multi-storey frame). Thus, in combination with secondary TMD, in all four systems are studied. It is found that all the four systems give fairly good and similar results for the structure (up to 57% overall response reduction). However, Single storey stacked TMD system reduces the response of Primary TMD the most. Thus, this is the most effective system. Also, it is observed that multi-storey or Multi DOF TMD can be used in place of single storey or Single DOF TMD to distribute the heavy TMD mass along the different DOFs.