Earthquake Resistant Design of Structures using the Variable Frequency Pendulum Isolator
Publication: Journal of Structural Engineering
Volume 128, Issue 7
Abstract
The essential properties of sliding isolators used for earthquake resistant design are period shift, energy dissipation, and the restoring mechanism. Isolation systems using a curved surface incorporate all of these in a single unit. The systems currently available have limitations due to their period and restoring force characteristics. The writers have recently proposed a new isolator called the variable frequency pendulum isolator (VFPI), which overcomes these limitations while retaining the advantages. The oscillation frequency of the VFPI continuously decreases with increase in sliding displacement, and the restoring force has an upper bound so that the force transmitted to the structure is bounded. The mathematical formulation for the response of multi-degree-of-freedom (MDOF) structures isolated using the VFPI has been discussed in this paper. Parametric studies have been carried out to examine the behavior of MDOF structures and structure-equipment systems isolated with the VFPI, friction pendulum system, and pure friction isolator. The VFPI performance is found to be effective and stable during low- and medium-intensity excitations, and fail-safe during high-intensity excitations. The VFPI is also found to exhibit robust performance for a wide range of isolator and ground motion characteristics, clearly demonstrating its advantages for vibration control of MDOF structures.
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References
Buckle, I. G., and Mayes, R. L.(1990). “Seismic isolation: History, application, and performance—A world view.” Earthquake Spectra, 6(2), 161–201.
Chalhoub, M. S., and Kelly, J. M.(1990). “Sliders and tension controlled reinforced bearings combined for earthquake isolation system.” J. Earthquake Eng. Struct. Dynam., 19(3), 333–344.
Clough, R. W., and Penziene, J. (1993). Dynamics of structures, 2nd Ed., McGraw-Hill, New York.
Igusa, T., and Der Kiureghian, A.(1985). “Dynamic characterization of two-degree-of-freedom equipment-structure systems.” J. Eng. Mech., 111(1), 1–19.
Kelly, J. M.(1986). “Aseismic base isolation: Review and bibliography.” J. Soil Dynam. Earthquake Eng., 5(4), 202–216.
Kelly, J. M. (1988). “Base isolation in Japan, 1988.” Rep. No. UCB/EERC-38/20, Earthquake Engineering Research Centre, Univ. of California, Berkeley, Calif.
Kelly, J. M. (1993). “State of the art and state of the practice in base isolation.” Seminar on Seismic Isolation, Passive Energy Dissipation and Active Control (ATC-17-1), Applied Technology Council, Redwood City, Calif.
Kemeny, Z. A. (1997). “Ball-in-cone seismic isolation bearing.” U.S. Patent No. 5599106, U.S. Patent and Trademark Office, Washington, D.C.
Mokha, A., Constantinou, M. C., and Reinhorn, A. M.(1990). “Teflon bearings in base isolation I: Testing.” J. Struct. Eng., 116(2), 438–454.
Mokha, A., Constantinou, M. C., Reinhorn, A. M., and Zayas, V. A.(1991). “Experimental study of friction-pendulum isolation system.” J. Struct. Eng., 117(4), 1201–1217.
Mokha, A., Amin, N., Constantinou, M. C., and Zayas, V. A.(1996). “Seismic isolation retrofit of large historic building.” J. Struct. Eng., 122(3), 298–308.
Mostaghel, N., Hejazi, M., and Tanbakuchi, J.(1983). “Response of sliding structures to harmonic support motion.” J. Earthquake Eng. Struct. Dynam., 11(3), 355–366.
Mostaghel, N., and Khodavedian, M.(1987). “Dynamics of resilient friction base isolator (R-FBI).” J. Earthquake Eng. Struct. Dynam., 15(3), 379–390.
Mostaghel, N., and Tanbakuchi, J.(1983). “Response of sliding structures to earthquake support motion.” J. Earthquake Eng. Struct. Dynam., 11(6), 729–748.
Naeim, F., and Kelly, J. M. (1999). Design of seismic isolated structures: From theory to practice, Wiley, New York.
Pranesh, M. (2000), “VFPI: An innovative device for aseismic design.” PhD thesis, Indian Institute of Technology, Bombay, India.
Pranesh, M., and Sinha, R. (1998). “Vibration control of primary–secondary systems using variable frequency pendulum isolator.” Proc., 11th Symposium on Earthquake Engineering, Univ. of Roorkee, Roorkee, India, 697–704.
Pranesh, M., and Sinha, R.(2000a). “VFPI: An isolation device for aseismic design.” J. of Earthquake Eng. Struct. Dynam., 29(5), 603–627.
Pranesh, M. and Sinha, R. (2000b). “Aseismic design of tall structures using variable frequency pendulum isolator.” Proc., 12th World Conf. Earthquake Engineering, Paper No. 284, Auckland, New Zealand.
Shustov, V. (1992). “Base isolation: Fresh insight.” Proc., 10th World Conf. on Earthquake Engineering, Balkema, Rotterdam, 4, 1983–1986.
Singh, M. P., and Suarez, L. E.(1992). “Dynamic condensation with synthesis of substructure eigenproperties.” J. Sound Vib., 159(1), 139–155.
Sinha, R. (1993). “Nonclassically damped structures.” Lecture Notes of One Week Interaction Programme—State of the Art on Seismic Qualification of Structures and Systems, Bhabha Atomic Research Centre, Mumbai, India, 71–80.
Sinha, R., and Pranesh, M. (1998). “FPS isolator for structural vibration control.” Proc., Int. Conf. on Theoretical, Applied, Computational and Experimental Mechanics (CD Volume), IIT, Kharagpur, India.
Tsai, C. S.(1997). “Finite-element formulations for friction pendulum seismic isolation bearings.” Int. J. Numer. Methods Eng., 40(1), 29–49.
Tsopelas, P., Constantinou, M. C., Kim, Y. S., and Okamoto, S.(1996). “Experimental study of FPS system in bridge seismic isolation.” J. Earthquake Eng. Struct. Dynam., 25(1), 65–78.
Uang, C. M., and Bertero, V. V.(1990). “Evaluation of seismic energy in structures.” J. Earthquake Eng. Struct. Dynami., 19(1), 77–90.
Wang, Y. P., Chung, L. L., and Liao, W. H.(1998). “Seismic response analysis of bridges isolated with friction pendulum bearings.” J. Earthquake Eng. Struct. Dynam., 27(10), 1069–1093.
Zayas, V. A., Low, S. S., and Mahin, S. A. (1987). “The FPS earthquake resisting system: Experimental report.” Rep. No. UCB/EERC-87/01, Earthquake Engineering Research Centre, Univ. of California, Berkeley, Calif.
Zayas, V. A., Low, S. S., and Mahin, S. A.(1990). “A simple pendulum technique for achieving seismic isolation.” Earthquake Spectra, 6(2), 317–333.
Zhou, Q., Lu, X., Wang, Q., Feng, D., and Yao, Q.(1998). “Dynamic analysis on structures base isolated by a ball system with restoring property.” J. Earthquake Eng. Struct. Dynam., 27(8), 773–791.
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Published In
Journal of Structural Engineering
Volume 128 • Issue 7 • July 2002
Pages: 870 - 880
Copyright
Copyright © 2002 American Society of Civil Engineers.
History
Received: Jun 15, 2000
Accepted: May 11, 2001
Published online: Jun 14, 2002
Published in print: Jul 2002
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