An approach for shake table performance evaluation during repair and retrofit actions |
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| Authors: | Christopher Trautner Yewei Zheng John S McCartney Tara Hutchinson |
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| Institution: | 1. Space Exploration Technologies, Hawthorne, CA, U.S.A.;2. Department of Structural Engineering, University of California, San Diego, La Jolla, CA, U.S.A. |
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| Abstract: | Large‐scale, servo‐hydraulic shake tables are a central fixture of many earthquake engineering and structural dynamics laboratories. Wear and component failure from frequent use may lead to control problems resulting in reduced motion fidelity, necessitating repairs and replacement of major components. This paper presents a methodology to evaluate shake table performance pre‐ and post‐repair, including the definition of important performance metrics. The strategy suggested is presented in the context of the rebuilding of a 4.9 × 3.1 m, 350‐kN‐capacity uniaxial shake table. In this case, the rebuild consisted of characterization of wear to table components, replacement of worn bearing surfaces, and replacement of hydraulic accumulators. To assess the effectiveness of the repair actions, sinusoidal and triangular waves, white noise, and earthquake histories were run on the table before and after the rebuild. The repair actions were successful in reducing the position and velocity dependence of friction, improving the ability of control algorithms to accurately reproduce earthquake motions. The maximum and average response spectral misfits in the period range of 0.1–2 seconds were reduced from approximately 50% to 15%, and from 5% to less than 2.5%, respectively. |
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| Keywords: | shake table testing structural control structural dynamics structural testing |
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