Abstract
A floor isolation system installed in a single floor or room in a fixed base structure is designed to protect equipment. With this configuration, the input motions to the floor isolation from the ground motions are filtered by the structure, leaving the majority of the frequency content of the input motion lower than the predominant frequency of the structure. The floor isolation system should minimize the acceleration to protect equipment; however, displacement must also be limited to save floor space, especially with long period motion. Semi-active control with an H ∞ control was adopted for the floor isolation system and a new input shaping filter was developed to account for the input motion characteristics and enhance the effectiveness of the H ∞ control. A series of shake table tests for a semi-active floor isolation system using rolling pendulum isolators and a magnetic-rheological damper were performed to validate the H ∞ control. Passive control using an oil damper was also tested for comparison. The test results show that the H ∞ control effectively reduced acceleration for short period motions with frequencies close to the predominant frequency of the structure, as well as effectively reduced displacement for long period motions with frequencies close to the natural frequency of the floor isolation system. The H ∞ control algorithm proved to be more advantageous than passive control because of its capacity to adjust control strategies according to the different motion frequency characteristics.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Lambrou V, Constantinou M C. Study of seismic isolation systems for computer floors. Rep. No. NCEER-94-0020, State University of New York at Buffalo, Buffalo, New York, 1994
Cui S, Bruneau M, Kasalanati A. Behavior of bidirectional spring unit in isolated floor systems. Journal of Structural Engineering, 2010, 136(8): 944–952
Liu S, Warn G P. Seismic performance and sensitivity of floor isolation systems in steel plate shear wall structures. Engineering Structures, 2012, 42: 115–126
Fan Y C, Loh C H, Yang J N, Lin P Y. Experimental performance evaluation of an equipment isolation using MR dampers. Earthquake Engineering & Structural Dynamics, 2009, 38(3): 285–305
Schiff A J. Northridge earthquake: lifeline performance and postearthquake response. Monograph No. 8, Technical Council on Lifeline Earthquake Engineering. New York: American Society of Civil Engineers, 1995
Nagarajaiah S, Sun X. Response of base-isolated USC hospital building in Northridge earthquake. Journal of Structural Engineering, 2000, 126(10): 1177–1186
Sato E, Furukawa S, Kakehi A, Nakashima M. Full-scale shaking table test for examination of safety and functionality of base-isolated medical facilities. Earthquake Engineering & Structural Dynamics, 2011, 40(13): 1435–1453
Hall J F, Heaton T H, Halling M W, Wald D J. Near-source ground motion and its effects on flexible buildings. Earthquake Spectra, 1995, 11(4): 569–605
Alhan C, Gavin H P, Aldemir U. Optimal control: Basis for performance comparison of passive and semiactive isolation systems. Journal of Engineering Mechanics, 2006, 132(7): 705–713
Yang J N, Lin S, Jabbari F. H1-based control strategies for civil engineering structures. Structural Control and Health Monitoring, 2004, 11(3): 223–237
Spencer B F Jr, Suhardjo J, Sain M K. Frequency domain optimal control strategies for a seismic protection. Journal of Engineering Mechanics, 1994, 120(1): 135–158
Suhardjo J, Spencer B F Jr, Kareem A. Frequency domain optimal control of wind-excited buildings. Journal of Engineering Mechanics, 1992, 118(12): 2463–2481
Spencer B F, Dyke S J, Sain M K, Carlson J D. Phenomenological model of magnetorheological damper. Journal of Engineering Mechanics, 1997, 123(3): 230–238
Dyke S J, Spencer B F Jr, Sain M K, Carlson J D. Modeling and control of magnetorheological dampers for seismic response reduction. Smart Materials and Structures, 1996, 5(5): 565–575
Nagarajaiah S, Narasimhan S. Smart base-isolated benchmark building: part II, phase I, sample controller for linear isolation system. Earthquake Engineering & Structural Dynamics, 2006, 13: 589–604
Narasimhan S, Nagarajaiah S. Smart base isolated buildings with variable friction systems: H1 controller and SAIVF device. Earthquake Engineering & Structural Dynamics, 2006, 35(8): 921–942
Agrawal A K, Xu Z, He W L. Ground motion pulse-based active control of a linear base-isolated benchmark building. Structural Control and Health Monitoring, 2006, 13(2–3): 792–808
Ramallo J C, Johnson E A, Spencer B F Jr. Smart base isolation systems. Journal of Engineering Mechanics, 2002, 128(10): 1088–1099
Shi Y, Becker T, Kurata M, Nakashima M. Design of a PI controller for MR dampers using damper force feedback. In: Proceeding of the First International symposium on Earthquake Engineering. 2012, 311–316
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Shi, Y., Becker, T.C., Kurata, M. et al. H ∞ control in the frequency domain for a semi-active floor isolation system. Front. Struct. Civ. Eng. 7, 264–275 (2013). https://doi.org/10.1007/s11709-013-0214-x
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s11709-013-0214-x