Tall building vibration control using a TM‐MR damper assembly

Abstract

This research investigates the seismic and harmonic response of a true free-plan tall building equipped with two tuned pendular inertial masses (TMs) and magnetorheological (MR) dampers. Construction of this proof-of-concept building was completed in 2007, and it is the first of its class in Chile. This article provides research results associated with this specific implementation; however, in order to make the results applicable to other building cases a parametric study was considered. A brief description of the structure and TM implementation together with the nonlinear equations of motion of the TM-MR damper assembly are presented. Building displacements and accelerations are computed and analyzed for a suite of subduction-type and near field ground motions. Besides, a new physical controller for the MR dampers is proposed and analyzed. The performance of this controller is compared with that of benchmark LQR controllers. In general, the TM-MR damper assembly improves the lateral performance of this structure for lateral harmonic excitations. However, the expected peak and RMS response modification factors and efficacy of the solution for earthquake excitations are strongly dependent on the frequency content of the excitation.damper to semiactively control a tuned mass, and the evaluation of the true performance of such solution for the free-plan building concept.It is well known that the efficacy of a TM depends on the frequency content of the excitation and the dynamic properties of the structure. There is general consensus that tuned masses are effective in reducing the response due to harmonic excitations [1] and wind excitations [2]. However, for seismic actions, there is no general agreement. For instance, some authors conclude that a TM combined with an optimal viscous damper is not effective in reducing the response due to earthquake excitations [3,4]. On the other hand, several analytical studies have shown that by connecting a TM to a semi-active MR device in structures subjected to earthquake and harmonic excitation, it is possible to improve the building performance [5][6][7][8][9]. In either case, questions such as the tuning frequency for a pendulum under large deformations, the optimal selection of damping in such case, and the effectiveness of a semiactive device versus a passive device, are not obvious decisions in this application.MR-dampers are semi-active MR fluid devices with a very low power requirement where a magnetic flux changes the fluid from a free-flowing linear viscous fluid state to a semi-solid state with controllable yield strength [10]. Due to this property, the reactive force applied on the TM by the MR-damper can be dynamically controlled within a range. The first full-scale application of an MR-damper was done in 2001, when two 30-ton MR-dampers were installed at the Tokyo National Museum of Emerging Science and Innovation. Additionally, different types of control strategies for a TM using MR-dampers have been investigated in the literature [6][7][8][9].This article invest...

Tall building vibration control using a TM‐MR damper assembly: Experimental results and implementation

“…A typical building plan of this building is presented elsewhere 10. The lateral force resisting system of the building consists of a shear‐wall core and a perimeter frame.…”

“…The total estimated building mass is 68 300 ton; 50% of it belongs to the basements whereas the other half is distributed uniformly on the superstructure. By performing an optimization procedure based on comparing the building response with that of an equivalent two degree‐of‐freedom system 11, the nominal uncoupled torsional‐to‐lateral frequency ratio in the Y ‐direction of the building was estimated as Ω=ω oy /ω θ =1.34, and the normalized stiffness eccentricity as .…”

“…Furthermore, the performances of the LQR optimal controller and the proposed physical controller were compared usingHS results. Building HS responses were also compared with analytical results 10. Finally, results from a pull‐back test on the flexible‐edge TM with and without the proposed controller are described.…”

Energy‐based predictive algorithm for semi‐active tuned mass dampers

“…This makes it more efficient in terms of suppressing the vibration response as compared with the PTMDs. Therefore, many researchers and design engineers have shown interest in the SATMDs . The implementation of the SATMDs has been advocated for the suppression of structural vibrations induced due to earthquake as well as wind excitations by researchers.…”

Semi-Active Pendulum to Control Offshore Wind Turbine Vibrations

“…Zemp et al [8] describes the implementation of a proof-of-concept pendulum tuned inertial mass magnetorheological (TM-MR) damper assembly in a tall building in Santiago, Chile, designed primarily to control building motions, and hence indirectly, interstory deformations.…”