This study presents a new method to find the optimal control forces for active tuned mass damper. The method uses three algorithms: discrete wavelet transform (DWT), particle swarm optimization (PSO), and linear quadratic regulator (LQR). DWT is used to obtain the local energy distribution of the motivation over the frequency bands. PSO is used to determine the gain matrices through the online update of the weighting matrices used in the LQR controller while eliminating the trial and error. The method is tested on a 10‐story structure subject to several historical pulse‐like near‐fault ground motions. The results indicate that the proposed method is more effective at reducing the displacement response of the structure in real time than conventional LQR controllers.

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This article presents a time varying wavelet‐based pole assignment (WPA) method to control seismic vibrations in multi‐degree of freedom (MDOF) structural systems. The discrete wavelet transform is used to determine the energy content over the frequency band of the response in real time. The frequency content was implemented in the Big Bang–Big Crunch algorithm to update the optimum values of the closed‐loop poles of the structural system adaptively. To calculate optimum gain matrix, a robust pole placement algorithm was used. The gain matrix is calculated online based on response characteristic in real time and must not be calculated a priori (offline) choice. The WPA is tested on a 10‐story structural system subject to several historical ground motions. It is observed that the WPA has advantages in some design problems. Numerical examples illustrate that the proposed approach reduces the displacement response of the structure in real time more than conventional linear quadratic regulator (LQR) controller.

Analytical investigations have been conducted to suppress vibration of tall building structures in the presence of uncertainty in structural dynamic characteristics. Three control algorithms consisting of probabilistic optimal control, fuzzy logic control and optimal control theories are combined to control system fluctuations and severe seismic excitations. A state-space reduced order model is constructed based on dominant observable and controllable Gramians of Lyapunov equations in order to prevent the control matrix singularity and achieve computational efficiency. Both types of active and semi-active control systems are installed in the buildings to reduce the seismic response. In the case of active control systems, both an active tuned mass damper and active mass driver are installed on the top floor. In the case of semi-active systems, such as electric rheological/magnetic rheological dampers, control devices are installed in selected story units. The class of multi-objective control constraints based on minimum control efforts with respect to stochastics evaluation criteria have been defined and satisfied. The fuzzy rule base matrices and fuzzy inference systems are appropriately constructed corresponding to regular forms of optimal control laws and input-output measured data in the control sequences. The performance and robustness of both active and semi-active control systems are investigated through a series of numerical simulations of a multistory building subjected to a wide range of seismic disturbances.

In this study, a new approach for global/local damage detection in a finite element model of structures, with limited sensors, is proposed using identified system Markov parameters. The proposed damage detection is directly related to the Markov parameters, locations of actuators and sensors. Also there is no explicit relation between DDA/ISMP and mode shapes. So, it is unnecessary to install a sensor at each DOF for measuring output to identify mode shapes unlike the other damage detection techniques in which mode shapes play an important role in damage identification. The stiffness of all elements of a structure is identified using the proposed DDA/ISMP. The effects of noise, numbers and locations of sensors on the identification precision are investigated. The results demonstrate that, with the limited sensors and the noise contamination in the measured responses, the DDA/ISMP can effectively identify the locations, types and quantities of damages, both locally and globally. To illustrate the efficiency of DDA/ISMP, a four-storey steel moment frame structure and a five-storey shear building are used. Our numerical results show that the DDA/ISMP technique in damage detection is more effective than the scheme proposed by Xu et al. Also, the time consumed in DDA/ISMP is considerably less than the method introduced by Xu.

The idea of using semi-active or active control devices within a base isolation system has been developed recently, since applying this system to building structures has some shortcomings such as the creation of large displacements at the base level and the systemʼs lack of adaptability to different seismic excitations. In this study, an integrated structural health monitoring and semiactive control scheme is proposed to enhance the seismic behavior of damaged isolated structures. The nonlinear behavior of an isolated structure is limited to the isolator level and the superstructure is assumed to remain linear. Then, using an online damage detection algorithm based on identified system Markov parameters and a semi-active fuzzy controller, the damage in the base isolator is mitigated and the seismic response of the structure is reduced. In addition, a magnetorheological damper is utilized as a well-studied semi-active actuator in the control system. The effectiveness of the proposed control system is evaluated through the numerical study of a six-degrees-of-freedom model of base-isolated buildings excited by various near-fault and far-field earthquake records. The results of the simulation show that the integrated algorithm is substantially effective in improving the dynamic behavior of isolated structures and reducing the damage in the isolator.

Integrated structural health monitoring (SHM) and vibration control has been considered recently by researchers. Up to now, all of the research in the field of integrated SHM and vibration control has been conducted using control devices and control algorithms to enhance system identification and damage detection. In this study, online SHM is used to improve the performance of structural vibration control, unlike previous research. Also, a proposed algorithm including integrated online SHM and a semi-active control strategy is used to reduce both damage and seismic response of the main structure due to strong seismic disturbance. In the proposed algorithm the nonlinear behavior of the building structure is simulated during the excitation. Then, using the measured data and the damage detection algorithm based on identified system Markov parameters (DDA/ISMP), a method proposed by the authors, damage corresponding to axial and bending stiffness of all structural elements is identified. In this study, a 20 t MR damper is employed as a control device to mitigate both damage and dynamic response of the building structure. Also, the interaction between SHM and a semi-active control strategy is assessed. To illustrate the efficiency of the proposed algorithm, a two bay two story steel braced frame structure is used. By defining the damage index and damage rate index, the input current of the MR damper is generated using a fuzzy logic controller. The obtained results show that the possibility of smart building creation is provided using the proposed algorithm. In comparison to the widely used strategy of only vibration control, it is shown that the proposed algorithm is more effective. Furthermore, in the proposed algorithm, the total consumed current intensity and generated control forces are considerably less than for the strategy of only vibration control.