No abstract

The sliding mode controller is one of the interesting classical nonlinear controllers in structural vibration control. From its apparition, in the middle of the twentieth century, this controller was a subject of several studies and investigations. This controller was widely used in the control of various semi-active or active devices in the civil engineering area. Nevertheless, the sliding mode controller offered a low sensitivity to the uncertainties or the system condition variations despite the presence of the Chattering defect. However, the adaptation law is one of the frequently used solutions to overcome this phenomenon offering the possibility to adapt the controller parameters according to the system variations and keeping the stability of the whole system assured. The chapter provides a sliding mode controller design reinforced by an adaptive law to control the desired state of an excited system. The performance of the adaptive controller is proved by numerical simulation results of a three-story excited structure.

Recently, structural vibration control has proved its capacity to save lives and keep structures safe during earthquakes. Furthermore, there is a wealth of research in both numerical and experimental studies. As a result, due to its simplicity and performance in mitigating structural vibrations generated by ground motions, semi-active control played a significant role in the majority of these studies. Nonetheless, the magnetorheological damper is the most often used semi-active device. In particular, the rheological fluid properties have gained adequate attention in earthquake energy dissipation and structural vibrations management, particularly in the civil engineering field. The semi-active control of three scaled excited structures is addressed in this study. A magnetorheological damper operated by a hybrid fuzzy sliding mode controller ensures the proposed control. However, to provide the appropriate current for the damper to operate, this proposed intelligent controller is combined with a clipped optimum algorithm. Otherwise, the numerical simulation results of the seismic excited scaled structure demonstrate the resilience of the suggested controller. As a result, four time-scaled seismic data are applied to the tested structure. Finally, the usefulness of the suggested semi-active control technique in mitigating earthquake structural vibration is demonstrated clearly in the compared controlled and uncontrolled responses.

Recently, the semi-active control of structural vibration has demonstrated its ability to preserve human life and keep structures safe during earthquakes. In the civil engineering area, the literature is full of investigation in both numerical and experimental research in which the Magneto-Rheological damper is the most used device. This paper investigates the semi-active control of three scaled excited structures. The proposed control is assured by a Magneto-Rheological damper controlled using a hybrid Fuzzy Sliding Mode controller. Although, a Clipped optimal algorithm is proposed to calculate the required current for the damper operating. Otherwise, the robustness of the suggested controller is proved by the obtained numerical results of the seismic excited scaled structure. Therefore, the tested structure is subjected to four time-scaled earthquake records. Finally, the effectiveness of the proposed semi-active control strategy in mitigating earthquake structural vibration is shown clearly in the compared controlled and uncontrolled responses. The simulation results show that the peak reduction reaches 65% under the 2011 Tōhoku earthquake. In addition, the performance indices prove the robustness of the proposed strategy.

The elevated water tanks are high importance structures for the humanity lifelines. These elevated tanks are considered as very sensitive structures for seismic movement conditions. Among the reasons for the damage and failure of elevated tanks is the design of its support systems. For this reason, several theoretical and experimental researchers studied the performance of this type of structure under seismic loading. The present study aims to demonstrate the supporting system effect on dynamic buckling of the elevated water tank, using three dimensional finite element technique the seismic response of two elevated water tanks was established taking into account the following factors; the fluidstructure Interaction (FSI), the wall flexibility, different nonlinear time histories analysis, and the material and geometric nonlinearity. Indeed, the application of three different instability criteria for the critical PGA estimate using two seismic excitations, namely El Centro and San Fernando earthquake. The numerical values are compared and no significant effect is found of the supporting system for convective fundamental frequency; however, strongly disturbed impulsive fundamental frequency. In addition, the effect of supporting system and the frequency content of the earthquake on PGAcr are clearly shown. A percent increase of PGAcr can reach up to 37.48%.