AbstractsEngineering

In general, the main purpose of a structural control system is to apply powerful control techniques that improve the behaviour of civil structures under various kinds of dynamic loading. The first part of this thesis presents novel applications of posicast and input shaping control schemes that have never previously been applied in the field of structural control. Numerical simulations of a benchmark three-story building with an MR damper are used to verify the efficiency of the proposed control theories. The superiority and effectiveness of the suggested schemes at reducing the structure’s responses were demonstrated using six evaluation criteria and by comparison to results achieved with well-established classical control schemes. Moreover, a comprehensive procedure for generating scaled real ground motion records appropriate for a seismic analysis and design of structures using the linear spectrum matching technique is presented based on a seismic hazard study. To efficiently control a structure, it is necessary to estimate its real-life dynamical behaviour. This is usually done using the Structural Identification approach, which is also addressed in this thesis. Structural Identification is commonly utilized to bridge the gap between the real structure and its modeled behaviour. It can also be used to evaluate the structure’s health, detect damage, and assess efficiency. Despite the extensive development of parametric time domain identification methods, their relative merits and the accuracy with which they predict the behaviour of vibrating structures are largely unknown because there have been few comparative studies on their performance under diverse test conditions, and they have not been verified against real-life data gathered over extended periods of time. Thus, the second part of this thesis focuses on applications of parametric and non-parametric models based on the Structural Identification approach in order to clarify their potential and applicability. In addition, a new strategy is proposed that combines this approach with techniques based on Singular Value Decomposition (SVD) and Complex Mode Indicator Function (CMIF) curves to detect structural damage. The methods developed in this work are used to predict the vertical frequencies of the top storey in a multi-storey building prefabricated from reinforced concrete in Stockholm, and to detect and locate damage in a benchmark steel frame. In addition, the non-parametric structural identification approach is used to investigate variation in the modal characteristics (frequency, damping, and mode shapes) of a steel railway bridge.