Performance of Nonseismic PTFE Sliding Bearings When Subjected to Seismic Demands
Publication: Journal of Bridge Engineering
Volume 21, Issue 1
Abstract
Laminated elastomeric bridge bearings incorporating a flat sliding layer of polytetrafluoroethylene (PTFE) provide service-level thermal displacement capacity to accommodate movements of a bridge superstructure in regions of low to moderate seismicity. These components also provide a potential source of displacement capacity, which is frequently neglected in seismic design. An experimental program has been carried out to evaluate behavioral characteristics and performance of steel-reinforced, laminated elastomeric bearings with PTFE at a flat sliding layer (which had not been designed for seismic demands) as primary quasi-isolation components for earthquakes by permitting large sliding displacements at a stainless steel-on-PTFE interface. The PTFE surfaces tolerated stress concentrations associated with eccentric loading stress distributions at moderate top plate displacements, with up to approximately 25% of the PTFE exposed at peak displacements. Larger displacements resulted in delamination and tearing of the PTFE, potentially leading to steel-on-steel sliding between the independent components. Bearings with moderately tall elastomer blocks were also susceptible to unstable rotated configurations with increasing displacements of the sole plate. Unseating of the sole plate from the elastomeric component occurred at displacements corresponding to the elastomer plan dimension in the direction of horizontal motion.
Get full access to this article
View all available purchase options and get full access to this article.
Acknowledgments
This article is based on the results of Illinois Center for Transportation (ICT) R27-70, Calibration and Refinement of Illinois’ Earthquake Resisting System Bridge Design Methodology. Illinois Center for Transportation R27-70 was conducted in cooperation with the ICT; IDOT; Division of Highways; and the DOT, Federal Highway Administration. The contents of this article reflect the view of the authors, who are responsible for the facts and the accuracy of the data presented herein. The contents do not necessarily reflect the official views or policies of the ICT, IDOT, or FHWA. The authors would like to thank the members of the project Technical Review Panel, chaired by D. H. Tobias and M. D. Shaffer of the IDOT, for their valuable assistance with this research.
References
AASHTO. (2010). Guide specifications for seismic isolation design, Washington, DC.
AASHTO. (2014). AASHTO LRFD bridge design specifications, Washington, DC.
ASTM. (2007). Standard specification for plain and steel-laminated elastomeric bearings for bridges, designation: D 4014-03, West Conshohocken, PA.
Buckle, I., Nagarajaiah, S., and Ferrell, K. (2002). “Stability of elastomeric isolation bearings: Experimental study.” J. Struct. Eng., 3–11.
Buckle, I. G., and Mayes, R. L. (1990). “Seismic isolation: History, application, and performance—A world view.” Earthquake Spectra, 6(2), 161–201.
Calvi, G. M., and Pavese, A. (1997). “Conceptual design of isolation systems for bridge structures.” J. Earthquake Eng., 1(1), 193–218.
Cardone, D. (2014). “Displacement limits and performance displacement profiles in support of direct displacement-based seismic assessment of bridges.” Earthquake Eng. Struct. Dyn., 43(8), 1239–1263.
Constantinou, M., Mokha, A., and Reinhorn, A. (1990). “Teflon bearings in base isolation II: Modeling.” J. Struct. Eng., 455–474.
Dolce, M., Cardone, D., and Croatto, F. (2005). “Frictional behavior of steel-PTFE interfaces for seismic isolation.” Bull. Earthquake Eng., 3(1), 75–99.
Fenz, D. M., and Constantinou, M. C. (2006). “Behavior of the double concave friction pendulum bearing.” Earthquake Eng. Struct. Dyn., 35(11), 1403–1424.
IDOT (Illinois Department of Transportation). (2012a). Bridge manual, Springfield, IL.
IDOT (Illinois Department of Transportation). (2012b). Standard specification for road and bridge construction, Springfield, IL.
Kikuchi, M., and Aiken, I. D. (1997). “An analytical hysteresis model for elastomeric seismic isolation bearings.” Earthquake Eng. Struct. Dyn., 26(2), 215–231.
Konstantinidis, D., Kelly, J. M., and Makris, N. (2008). “Experimental investigations on the seismic response of bridge bearings.” Rep. No. EERC 2008-02, Earthquake Engineering Research Center, College of Engineering, Univ. of California, Berkeley, CA.
Kulak, R. F., and Hughes, T. H. (1992). “Mechanical tests for validation of seismic isolation elastomer constitutive models.” DOE facilities programs, systems interaction, and active/inactive damping, C.-W. Lin et al., eds., Vol. 229, ASME Publication PVP, New York, 41–46.
Makris, N., and Kampas, G. (2013). “The engineering merit of the ‘effective period’ of bilinear isolation systems.” Earthquakes Struct., 4(4), 397–428.
Mayes, R. L., and Naeim, F. (2001). “Design of structures with seismic isolation.” The seismic design handbook, F. Naeim, ed., Kluwer Academic Publishers, Boston, 724–755.
Mokha, A., Constantinou, M., and Reinhorn, A. (1990). “Teflon bearings in base isolation I: Testing.” J. Struct. Eng., 438–454.
Mori, A., Moss, P. J., Cooke, N., and Carr, A. J. (1999). “The behavior of bearings used for seismic isolation under shear and axial load.” Earthquake Spectra, 15(2), 199–224.
Roeder, C. W., Stanton, J. F., and Taylor, A. W. (1987). “Performance of elastomeric bearings.” National cooperative highway research program 298, Transportation Research Board, Washington, DC.
Stanton, J. F., and Roeder, C. W. (1982). “Elastomeric bearings design, construction, and materials.” National cooperative highway research program 248, Transportation Research Board, National Research Council, Washington, DC.
Steelman, J. S. (2013). “Sacrificial bearing components for quasi-isolated response of bridges subject to high-magnitude, low-probability seismic hazard.” Ph.D. dissertation, Univ. of Illinois at Urbana-Champaign, Urbana, IL.
Steelman, J. S., et al. (2013a). “Experimental behavior of steel fixed bearings and implications for seismic bridge response.” J. Bridge Eng., A4014007.
Steelman, J. S., Fahnestock, L. A., Filipov, E. T., LaFave, J. M., Hajjar, J. F., and Foutch, D. A. (2013b). “Shear and friction response of nonseismic laminated elastomeric bridge bearings subject to seismic demands.” J. Bridge Eng., 612–623.
Taylor, A. W., and Igusa, T. (2004). Primer on seismic isolation, ASCE, Reston, VA.
Tobias, D. H., Anderson, R. E., Hodel, C. E., Kramer, W. M., Wahab, R. M., and Chaput, R. J. (2008). “Overview of earthquake resisting system design and retrofit strategy for bridges in illinois.” Pract. Period. Struct. Des. Constr., 147–158.
Information & Authors
Information
Published In
Journal of Bridge Engineering
Volume 21 • Issue 1 • January 2016
Copyright
© 2015 American Society of Civil Engineers.
History
Received: Aug 11, 2014
Accepted: Jan 13, 2015
Published online: May 15, 2015
Discussion open until: Oct 15, 2015
Published in print: Jan 1, 2016
Notes
Based on the Ph.D. dissertation of Joshua S. Steelman.
Authors
Metrics & Citations
Metrics
Citations
Download citation
If you have the appropriate software installed, you can download article citation data to the citation manager of your choice. Simply select your manager software from the list below and click Download.