Analytical and experimental studies on large scale, real-time pseudodynamic testing

The pseudodynamic (PSD) test method is a displacement-based experimental technique that is used to simulate the seismic response of structures. It utilizes feedback signals from a test structure in a numerical integration algorithm to sequentially solve the equations of motion to determine command displacements. The command displacements are imposed on a test structure using hydraulic actuators. To avoid the fabrication and testing of the entire structure, the hybrid PSD test method is used where only a portion of the structure is experimentally tested (the experimental substructure). The experimental substructure degrees of freedom are coupled to an analytical model (analytical substructure) that represents the remaining part of the structure.; With the interest by practitioners in the use of velocity-dependent devices (e.g., dampers) to mitigate seismic hazards in structures, there currently exists the need to perform large-scale, real-time testing to evaluate the performance of these types of devices and their effectiveness in reducing seismic damage in structures. The real-time hybrid PSD test method is an ideal experimental method to address this need.; The main focus of the research described in this dissertation is the development of a methodology to successfully implement the large-scale, real-time PSD testing method, perform experiments, and evaluate the success of the test results. To fulfill these objectives, the sources of error in real-time PSD testing and real-time hybrid PSD testing methods are identified and evaluated. The boundary of stability with respect to the critical error source (i.e., time delay) is developed, enabling the evaluation of the feasibility of conducting a real-time PSD test, to set the performance criteria for the servo-hydraulic controller, and reveal the need, if any, to design additional compensators. Indicators are developed to evaluate and compare the error introduced by the hydraulic actuators, whereby the accuracy of the real-time test results can be reliably assessed. A computational platform is established utilizing MATLAB/Simulink, where the components of the real-time PSD hybrid test method that includes the integration algorithm, servo-hydraulic system, analytical and experimental substructures are modeled. Numerical simulations of real-time hybrid PSD tests are performed to verify system stability and determine the demand on equipment. The real-time PSD and real-time hybrid PSD test methods are implemented to establish the capabilities of the Lehigh NEES Equipment Site. Results from experiments are evaluated and presented.