Control Synthesis and Analysis of a Multiple Seismic Shake Table Test System

Control Synthesis and Analysis of a Multiple Seismic Shake Table Test System

Shake table testing is regarded as one of the most straightforward methods of evaluating the seismic response of structural systems subjected to earthquake ground motions. A shake table test is considered representative as long as the desired acceleration time history can be reproduced accurately. As a result, acceleration tracking control of a shake table becomes crucial for shake table testing. However, some structures, such as long-span bridges and piping systems, by nature, are subjected to spatially varying earthquake ground motion. This kind of motion cannot be reproduced by using a single shake table. Thus, a multiple shake table test system is needed to meet these requirements. This is achieved by using a different configuration for each table. In this study, a multiple shake table test system constructed at National Center for Research on Earthquake Engineering is first introduced. Then, a control framework for uni-axial shake tables is proposed, which incorporates a feedback controller into a weighted command shaping controller. This improves the acceleration performance of the shake table. This control framework is verified by several shake table tests with and without a flexible steel shear building. Finally, the control framework is further applied to controlling a multiple shake table test system for preliminary studies.