Stability of Elastomeric Seismic Isolation Bearings
Publication: Journal of Structural Engineering
Volume 125, Issue 9
Abstract
Elastomeric seismic isolation bearings are subjected to large axial loads and lateral displacements during strong earthquakes. The existing Koh-Kelly model for elastomeric bearings accounts for axial load effects on horizontal stiffness. This linear model is based on small displacements and rotations and predicts stable postcritical behavior or increasing critical load with increasing horizontal displacement; however, unstable postcritical behavior is observed in the bearing test results presented in this study. The analytical model developed in this study, based on the Koh-Kelly model, includes large displacements, large rotations, and nonlinearity of rubber, and it predicts unstable postcritical behavior. The formulation of the analytical model, calibration, and verification using experimental results are presented. It is shown that: (1) the critical load reduces with increasing horizontal displacement; and (2) the horizontal stiffness reduces with increasing horizontal displacement and axial load. It is also shown that the critical load capacity at a horizontal displacement equal to the width of the bearing is not equal to zero, as predicted by the approximate procedure used in design, but higher.
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References
1.
Buckle, I. G., and Kelly, J. M. ( 1986). “Properties of slender elastomeric isolation bearings during shake table studies of a large-scale model bridge deck.” Joint Sealing and bearing systems for concrete structures, Vol. 1, American Concrete Institute, Detroit, Mich., 247–269.
2.
Buckle, I. G., and Liu, H. (1993). “Stability of elastomeric seismic isolation systems.” Proc., Seminar on Seismic Isolation, Passive Energy Dissipation, and Control, Applied Technology Council, Redwood City, Calif., 293–305.
3.
Buckle, I. G., and Liu, H. (1994). “Experimental determination of critical loads of elastomeric isolators at high shear strain.” NCEER Bull., 8(3), 1–5.
4.
Buckle, I. G., Nagarajaiah, S., and Ferrell, K. (1999). “Stability of elastomeric seismic isolation bearings: experimental study.”J. Struct. Engrg., ASCE, in review.
5.
Derham C. J., and Thomas, A. G. ( 1981). “The design of seismic isolation bearings.” Control of seismic response of piping system and other structures. University of California, Berkeley, Calif., 21–36.
6.
Ferrell, K. ( 1996). “Stability of elastomeric seismic isolation bearings,” MS thesis, University of Missouri, Columbia.
7.
Gent, A. N. (1964). “Elastic stability of rubber compression springs.” J. Mech. Engrg. Sci., 6(4), 318–326.
8.
Haringx, J. A. (1948). “On highly compressible helical springs and rubber rods and their application for vibration-free mountings. I.” Philips Res. Rep., 3, 401–449.
9.
Haringx, J. A. (1949a). “On highly compressible helical springs and rubber rods and their application for vibration-free mountings. II.” Philips Res. Rep., 4, 49–80.
10.
Haringx, J. A. (1949b). “On highly compressible helical springs and rubber rods and their application for vibration-free mountings. III.” Philips Res. Rep., 4, 206–220.
11.
Kelly, J. M. (1997). Earthquake resistant design with rubber, 2nd Ed., Springer Verlag, New York.
12.
Koh, C. G., and Kelly, J. M. (1986). “Effects of axial load on elastomeric bearings.” UCB/EERC-86/12, Earthquake Engrg. Res. Ctr., University of California, Berkeley, Calif.
13.
Koh, C. G., and Kelly, J. M. (1988). “A simple mechanical model for elastomeric bearings used in base isolation.” Int. J. Mech. Sci., 30(12), 933–943.
14.
Koh, C. G., and Kelly, J. M. (1989). “Viscoelastic stability model for elastomeric isolation bearings.”J. Struct. Engrg., ASCE, 115(2), 285–302.
15.
Nagarajaiah, S., Reinhorn, A. M., and Constantinou, M. C. (1991). “3D-BASIS nonlinear dynamic analysis of three-dimensional base isolated structures. II.” Rep. NCEER-91-0005, National Center for Earthquake Engineering Research, SUNY, Buffalo.
16.
Roeder, C. W., Stanton, J. F., and Taylor, A. W. (1987). “Performance of elastomeric bearings.” NCHRP Rep. 298, Transp. Res. Board, National Research Council, Washington, D.C.
17.
Simo, J. C., and Kelly, J. M. (1984). “Finite element analysis of the stability of multilayer elastomeric bearings.” Engrg. Struct., 6, 162–174.
18.
Stanton, J. F., Scroggins, G., Taylor, A. W., and Roeder, C. W. (1990). “Stability of laminated elastomeric bearings.”J. Engrg. Mech., ASCE, 116(6), 1351–1371.
Information & Authors
Information
Published In
Journal of Structural Engineering
Volume 125 • Issue 9 • September 1999
Pages: 946 - 954
History
Received: Apr 14, 1997
Published online: Sep 1, 1999
Published in print: Sep 1999
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