Vibration Control Of Tall Buildings Research Articles

Optimal Design of Variable Peripheral Mass Dampers in Passive and Active Vibration Control of Tall Buildings

Optimal Design of Variable Peripheral Mass Dampers in Passive and Active Vibration Control of Tall Buildings

Wind-induced vibration control of tall buildings by designing the overhead fire water tanks as compliant deep tank dampers-inerter

Building codes often mandate the installation of overhead fire water tanks (OFWTs) on multi-storeyed buildings. The present study proposes a cost-effective solution by utilizing these OFWTs as tuned liquid dampers (TLDs) in tall buildings to improve serviceability under wind-induced excitation. However, designing OFWTs as TLDs is often hindered by the deep nature of the OFWTs and practical constraints in dimensioning the tank as per the tuning requirement. To alleviate these hindrances, the OFWT is designed as a compliant deep tank damper-inerter (CDTDI). A compliant damper system is achieved by connecting the tank with the building through spring and dashpot elements. This allows relative motion of the whole tank with respect to the building. Further, an inerter is employed to improve the efficiency of the compliant damper. Three example buildings, 20-, 30-, and 40-storeyed, are considered and modeled as multi-degrees-of-freedom (MDOF) systems. The CDTDI-MDOF structural system’s motion equations are formulated. An excitation-independent, genetic algorithm-based single-objective optimization is performed to estimate the optimum CDTDI parameters. Sequentially, the 2nd-order or H2 and infinity or H∞ norms of the transfer function of the roof displacement are chosen as objective function. The efficacy of the CDTDI is examined by subjecting the structure to 10 simulated wind excitations. The results reveal the proficiency of the CDTDI in controlling the multiple modes of the structure, alongside providing significant damping. The CDTDI induces up to 25 and 21 % reduction, respectively, in the peak roof displacement and peak roof acceleration of the example buildings. Further, CDTDI with parameters obtained through H∞ optimization is found to be relatively better performing.

Parametric study of wind-induced vibration control of tall buildings using TMD and TLCD systems

The effectiveness of tuned mass and liquid column dampers (TMD and TLCD systems) in reducing the along-wind and crosswind vibrations of tall buildings is parametrically investigated. A numerical example of a tall building is presented and the structure is modeled as a multi-degrees-of-freedom vertical cantilever beam with beam elements and the masses lumped at the nodes. The responses of the structure are determined using frequency-domain analysis and random vibration theory. The study is carried out parametrically and the effects of various parameters such as basic wind speed, damper mass, and the geometric characteristics of the TLCD system are discussed. The results indicate that both TMD and TLCD systems effectively reduce structural vibrations especially acceleration for a wide range of basic wind speeds. The performance of the TLCD system was highly dependent on the ratio of horizontal to total length of the liquid column, and with increasing the horizontal length, the control efficiency of the TLCD became closer to the that of the TMD. Although the control efficiency of TMD is relatively higher than that of the TLCD, however, higher safety, lower installation and maintenance cost and multi usages of TLCD make it more appropriate for practical applications.

Adaptive Negative Stiffness Device based nonconventional Tuned Mass Damper for seismic vibration control of tall buildings

Adaptive Negative Stiffness Device (ANSD) has been developed recently for passive vibration control of structures. ANSD emulates negative stiffness behavior (by exerting force toward the direction of motion) to a structure, so that, the combined structure-ANSD system shows smooth elasto-plastic force-deformation behavior with virtual yielding at target (“engaging”) displacement. The device has been studied analytically and its behavior has been demonstrated experimentally in simply supported bridge model and in Single Degree of Freedom (SDOF) structure considering limited input excitations. However, efficient and cost-effective exploitation of true potential of ANSD deserves further studies. With this being the eventual goal, in this study, we explore the performances of ANSD in seismic vibration control of a tall building by implementing a nonconventional Tuned Mass Damper (TMD) with drift control. In absence of a methodology for choice of ANSD parameters in literature, reported till date, we employ a tuning criteria for nonconventional TMD, on which the drift control is imposed as a constraint, given the special significance of drifts in tall buildings. The criteria of tuning and drift control are shown to be mutually conflicting and an algorithm is presented to address the same. Simplifying assumptions are made to develop the tuning criteria in presence of nonlinearity in ANSD and P−δ nonlinearity in tall building. A Reduced Order Modeling (ROM) approach for the building-ANSD system is developed to facilitate the algorithmic computations. Robustness of our design approach is shown under an acceptable level of detuning of TMD and near fault pulse type motions. Comparative assessment with a conventional design approach is presented to show the improvements. A step by step illustration of the developed methodology is briefly touched on in context of modern performance based approach. The study is a first step toward the possible utility of ANSD in controlling seismic vulnerability of tall buildings.

Seismic Control of Tall Buildings Using Distributed Multiple Tuned Mass Dampers

The vibration control of tall buildings during earthquake excitations is a challenging task because of their complex seismic behavior. This paper investigates the optimum placement and properties of the tuned mass dampers (TMDs) in tall buildings, which are employed to control the vibrations during earthquakes. An algorithm was developed to spend a limited mass either in a single TMD or in multiple TMDs and distribute it optimally over the height of the building. The nondominated sorting genetic algorithm II (NSGA‐II) method was improved by adding multivariant genetic operators and utilized to simultaneously study the optimum design parameters of the TMDs and the optimum placement. The results showed that, under earthquake excitations with noticeable amplitude in higher modes, distributing TMDs over the height of the building is more effective in mitigating the vibrations compared to the use of a single TMD system. From the optimization, it was observed that the locations of the TMDs were related to the stories corresponding to the maximum modal displacements in the lower modes and the stories corresponding to the maximum modal displacements in the modes which were highly activated by the earthquake excitations. It was also noted that the frequency content of the earthquake has significant influence on the optimum location of the TMDs.

Wind-induced vibration control of tall buildings using hybrid buckling-restrained braces

SUMMARY A buckling-restrained brace (BRB) is a system with excellent earthquake-proof performance, but it does not dissipate energies caused by the load from weak earthquakes or winds. A hybrid BRB (H-BRB), which improved the performance of the BRB, is a type of composite damper system consisting of a BRB and a viscoelastic damper. To explain the wind-induced vibration control performance of H-BRB, a 40-story steel building was designed and used as an analysis model in this study, on the basis of the damping ratio from a structural performance test, using normal steel braces, BRB and H-BRB. In addition, to evaluate the optimal location of H-BRB, a time-history analysis of four models was conducted in the study. For such time-history analysis, wind-load data in a 10-year recurrence interval, which were calculated from the wind tunnel test, were used. The result of the time-history analysis showed that H-BRB is effective in improving both the lateral stiffness and serviceability of a building using the existing BRB. It also confirmed that it is most effective to position H-BRBs mainly on the lower stories. Copyright © 2012 John Wiley & Sons, Ltd.

Sequential design of multioverlapping controllers for structural vibration control of tall buildings under seismic excitation

In this article, a computationally effective strategy to obtain multioverlapping controllers via the inclusion principle is applied to design a state-feedback multioverlapping linear-quadratic regulator controller for a 20-story building. The proposed semidecentralized controller only requires state information of neighboring stories to compute the corresponding control actions. This particular information exchange configuration allows introducing a dramatic reduction in the transmission range required for a wireless implementation of the communications system. More specifically, just a one-story transmission range is required by the proposed multioverlapping controller, while a full-building transmission range would be necessary in a classical centralized design. From a computational point of view, the presented design strategy only involves the actual computation of a reduced set of low-dimension controllers. The numerical simulations indicate that despite the simplified low-dimension design and the severe information exchange constraints, the proposed semidecentralized multioverlapping controller achieves a surprisingly high level of seismic attenuation when compared with the centralized linear-quadratic regulator controller.

Discrete‐Time Multioverlapping Controller Design for Structural Vibration Control of Tall Buildings under Seismic Excitation

In this paper, a computationally effective strategy to obtain multioverlapping controllers via the Inclusion Principle is applied to design discrete‐time state‐feedback multioverlapping LQR controllers for seismic protection of tall buildings. To compute the corresponding control actions, the proposed semidecentralized controllers only require state information from neighboring stories. This particular configuration of information exchange allows introducing a dramatic reduction in the transmission range required for a wireless implementation of the communication system. To investigate the behavior of the proposed semidecentralized multioverlapping controllers, a proper simulation model has been designed. This model includes semiactive actuation devices with limited force capacity, control sampling times consistent with the communication latency, time‐delayed state information, and communication failures. The performance of the proposed multioverlapping controllers has been assessed through numerical simulations of the seismic response of a 20‐story building with positive results.

Adaptive passive, semiactive, smart tuned mass dampers: identification and control using empirical mode decomposition, hilbert transform, and short-term fourier transform

Tuned mass dampers (TMD), active mass dampers (AMD) and hybrid mass dampers (HMD) have been widely applied for vibration control of tall buildings and bridges in the past decade. Recently, the author and his coworkers have developed semiactive or smart tuned mass dampers (STMD) using semiactive variable stiffness systems. STMD's are superior than TMD's in reducing the response of the primary structure. In case the fundamental frequency of the primary structure changes due to damage or deterioration, then the TMD will be off-tune; hence, it will lose its effectiveness significantly, whereas the STMD is robust against such changes as it is always tuned. The author and his coworkers have shown that STMD can provide performance similar to AMD/HMD, but with an order of magnitude less power consumption. In this paper, new adaptive length pendulum STMD's are introduced. The concept of adaptive passive tuned mass dampers (APTMD) is introduced. APTMD is a TMD in which a tuning parameter such as frequency is adjusted passively based on some local mechanical feedback (displacement, velocity, rotation, etc.), but without associated sensing and computer feedback needed in a STMD. Also, the concept of STMD is further developed in this paper and practical STMD's and APTMD's implementation in USA, Japan, and China is presented. Systems with semiactive variable stiffness devices and STMD/APTMD are linear time varying systems (LTV); hence, algorithms are needed for their identification and control. Recently, the author and his coworkers have developed instantaneous frequency tracking control algorithms. In this paper new system identification algorithms based on time frequency methods, such as Empirical Mode Decomposition (EMD), Hilbert Transform (HT), and short time Fourier transform (STFT), are developed. New real time tuning algorithms that identify the instantaneous frequency of the LTV system and tune the STMD are developed based on EMD, HT, and STFT. Systems with STMD subjected to stationary (harmonic, sinsweep, and white-noise) and nonstationary (earthquake) excitations are investigated. The effectiveness of the STMD systems and the new identification and control algorithms is demonstrated by means of numerical simulations and experimental validation. Copyright © 2009 John Wiley & Sons, Ltd.

Active Control of Cross Wind Response of 76-Story Tall Building Using a Fuzzy Controller

This paper focuses on the benchmark problem application regarding the vibration control of tall buildings under cross wind excitation. The building under consideration is the 76-story, 306-m tall r...

An experimental study of active control of wind-induced vibration of super-tall buildings

A control strategy named Sinusoidal Reference Strategy is developed for adaptive feedforward control of wind-induced vibration of super-tall buildings. In this approach a high-frequency sinusoidal signal is adopted as the reference signal for the strategy. Some shortcomings of the conventional adaptive feedforward control method can be overcome. A MDOF general building aeroelastic model with a square cross-section was tested in a wind tunnel. The testing results show that the present strategy can reduce vibration effectively, and can adapt to wind-induced vibration control of tall buildings with dynamic uncertainties and modeling errors.

Active control of along wind response of tall building using a fuzzy controller

This paper focuses on the benchmark problem application regarding the vibration control of tall buildings under along wind excitation. The building under consideration is the 76-story, 306 meter tall reinforced concrete office tower proposed for the city of Melbourne, Australia. The adopted control scheme consists of an Active Tuned Mass Damper (ATMD) where the control action is achieved by a Fuzzy Logic Controller (FLC). The main advantage of the fuzzy controller is its inherent robustness and ability to handle any non-linear behaviour of the structure. This benchmark study is based on specified design constraints for the ATMD to be considered in the design of the proposed control scheme. The robustness of the controller has been demonstrated through the uncertainty in stiffness (+15% and −15% variation from initial stiffness) of the building. The results of the simulation show a good performance by the fuzzy controller for all cases tested. Also the results show that the fuzzy controller performs slightly better than the LQG controller, while possessing several advantages over the LQG controller.

Study on Proper Distribution of High-Damping Rubber Dampers for Vibration Control of Tall Buildings Using Genetic Algorithm. 3rd Report. Satisfy the Multiple Design Targets in the Same Time.

The optimal placement method or procedure of a storey-installation type damper for the vibration control of structures and buildings has not yet been established though the devices them-selves are developed actively. Therefore, in most cases, these dampers have been installed uniformly in each storey of the building. However, it can be thought that this method is not so much effective in reducing vibrations in the structure because the significant difference in the absorbed between lower and higher storeys is produced. This study attempts to apply the genetic algorithm (GA) to determine the proper distribution for the storey-installation type damper rapidly and easily. In this paper, multiple conditions are satisfied by applying multi-objective optimization theory in the evaluation function of GA. Then, GA also decides the proper number of device to mitigate the vibration considering the economical requirements to cut down the cost of using the dampers.

Optimal design of wind-induced vibration control of tall buildings and high-rise structures

The most common used control device on tall buildings and high-rise structures is active and passive tuned mass damper (ATMD and TMD). The major advantages of ATMD and TMD are discussed. The existing installations of various passive/active control devices on real structures are listed. A set of parameter optimization methods is proposed to determine optimal parameters of passive tuned mass dampers under wind excitation. Simplified formulas for determining the optimal parameters are proposed so that the design of a TMD can be carried out easily. Optimal design of wind-induced vibration control of frame structures is investigated. A thirty-story tall building is used as an example to demonstrate the procedure and to verify the efficiency of ATMD and TMD with the optimal parameters.

For A Better Acoustical Environment. 2. Active Vibration Control of Tall Buildings.

For A Better Acoustical Environment. 2. Active Vibration Control of Tall Buildings.

Unified dynamic absorber design formulas for wind-induced vibration control of tall buildings

The objective of this paper is to establish some unified design formulas for various kinds of passive dynamic absorber for wind-induced vibration control of tall buildings. A total of five different passive dynamic absorbers (TMD, TLCD, LCVA, C-TLD and R-TLD) are considered in this study. Firstly, unified equations of motion for the building–absorber system under wind-induced excitation are presented. A set of unified formulas for the optimal properties and the equivalent damping ratios for these five dynamic absorbers are then derived analytically. The Shanghai Central Plaza, which is a thirty-nine-story reinforced-concrete building, is used as an example to demonstrate the procedure and to verify the accuracy of the unified approach. The results show that these unified formulas provide direct performance evaluation and comparison between the five dynamic absorbers for the control of wind-induced vibration of tall buildings. © 1998 John Wiley & Sons, Ltd.

Unified dynamic absorber design formulas for wind‐induced vibration control of tall buildings

Unified dynamic absorber design formulas for wind‐induced vibration control of tall buildings

Control Methods for Active Mass Damper Using Linear Motor for Vibration Control of Tall Buildings.

Linear motors are promising actuators for active mass dampers, because driving mechanisms using them become more simple, reliable and efficient than those of current mass dampers which use AC servomotors and hydraulic actuators. Control methods using directly measured absolute accelerations of the buildings as feedback signals, are expected to he more reliable than those of current mass dampers using relative velocities and displacements to the ground which are calculated from the absolute accelerations. In this study, controllers were designed for the acceleration feedback control for a mass damper using a linear motor, based on the H∞ control theory and a model-matching method. A gain-scheduled control law was also developed for the acceleration feedback control. Excitations tests were carried out for a 5-story building model of a 5 800 kg total mass and a 3.4 m height with a mass damper model on the roof. Through the tests, it was shown that the H∞ controllers had higher performance than the model-matching controllers, and the gain-scheduled control law was very effective.

Designing Water Dampers for Suppressing Along-Wind and Cross-Wind Building Vibration

The purpose of this paper is to establish some simple and useful water damper design formulas for wind-Induced vibration control of tall buildings. A total of four different types of water dampers (CTLD, RTLD, TLCD and LCVA) are considered in this study. These four types of water dampers represent a stream of reliable and effective passive control devices which are well studied and ready to be used on flexible buildings and structures. A set of unified equations of motion for the building-damper system under wind-Induced excitation are presented. First the along-wind and the cross-wind responses for a tall building are revisited and derived. The effect of water dampers on the suppression of building response is then demonstrated through establishing an equivalent damping ratio for the water dampers. It is seen that the addition of water dampers would increase the damping ratio of the building and thus reduce its wind-induced vibration. A set of formulas for the optimal properties and the optimal equivalen...

Vibration Control of High-Rise Buildings Using High-Damping Rubber Damper. 3rd Report. Temperature Dependency and Durability of Cylinder Type High-Damping Rubber Damper.

A new type of high-damping rubber damper for vibration control of tall buildings has been being developed in this study. This paper describes the temperature dependency of the damper which will be an important problem in vibration control systems using high molecule material. The tests were carried out in two different conditions from the viewpoint of the temperature variation of vibration control material into the dampers. One is the variation of environmental temperature around the damper and the other is the self-generated heat in the damper which will be induced by the cyclic loading such as earthquake or wind. Moreover, the durability of damper was investigated by following tests; breaking test, static tests and cyclic loading tests under excessive shear strain amplitude. As the results, it was confirmed that the temperature dependency of the damper would not much affect to the energy absorbing characteristics even in the case of the practical use and the durability of the damper was highly enough against the large earthquakes by means of its strong adhesive characteristics.