Experimental testing is an essential tool for understanding how structures respond to extreme events. Methods currently used to determine the behavior of structural systems subjected to dynamic loading are quasi-static, shaking-table, and hybrid (or pseudodynamic) testing. In hybrid testing, the response of the structure is calculated numerically on a computer, and then the restoring forces from the structure are obtained by applying the calculated displacements to a test specimen. The combination of physical testing with numerical simulation provided by hybrid testing facilitates accurate and efficient testing of large and complex structural systems.; Because conventional hybrid testing is executed at slow speeds, the method is not applicable for structures with rate-dependent components. To allow testing of such structures, researchers have proposed a variation of the method called real-time hybrid testing in which the experiment is executed in real time.; Real-time hybrid testing is challenging because it requires execution of each testing cycle within a fixed, small increment of time (typically less than 10 msec). Furthermore, unless appropriate compensation for time delays and actuator dynamics is implemented, stability problems are likely to occur. Traditionally, researchers have lumped the effects of time delays and actuator dynamics together and treated them as a constant time delay; techniques were then developed to compensate for this total time delay. However, these techniques only perform well when the delay is small compared to the fundamental period of the structure.; The focus of this dissertation is to develop a new approach for real-time hybrid simulation that uses model-based methods to compensate for time delays and actuator dynamics and combines fast hardware and software (for high-speed computations and communication) with high performance hydraulic components.; The studies presented in this dissertation extend the capabilities of real-time hybrid testing by facilitating accurate testing of structural systems with larger natural frequencies (e.g., stiff structures or multi-degree-of-freedom systems) and handling larger delays/lags which are typically associated with actuators with high force capacity. Furthermore, these studies demonstrate that real-time hybrid testing is an effective and practical technique to evaluate the response of structures incorporating devices for passive and semiactive structural control (e.g., MR dampers).
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