Seismic Vulnerability of the Highway System

Task  D1-1: Performance Review of Seismically Isolated Structures

Subject Area: : Earthquake Protective Systems 
Research Year 2

Principal Investigator(s) and Institution(s)

George C. Lee, University at Buffalo
Ian G. Buckle, University of Nevada, Reno


This task will review and summarize the performance of highway bridge seismic isolation systems and bridge bearings designed to reduce earthquake forces that are transmitted between bridge sub- and superstructures. Major emphasis in this will be a review of the seismic performance of structures with isolation bearings during the Northridge and Kobe earthquakes. Additional information will be included for the Turkey and Taiwan earthquakes of 1999, if available by time of publication.


Seismic isolation is currently regarded as a relatively well-developed technology for reducing the seismic demands on highway bridge substructures and foundations. However, field experience during moderate-to-large earthquakes is limited, and there has been little definitive reporting on performance to date. There is conflicting evidence about inadequate designs, but the reason for this confusion may relate to the nature of ground motion rather than the isolators themselves. These issues need to be resolved.

During Research Year 1, approximately 40 references related to the performance of isolation bearings and bridges during earthquakes weres gathered and reviewed. Based on the information in these references, a draft report was nearly completed, but the 1999 Taiwan and Turkey earthquakes delayed the reporting process. Both of these earthquakes subjected isolated bridges to ground motions, which will undoubtedly shed further light on this topic and provides the PI the opportunity to improve the state of knowledge with the report. Consequently, the completion of the draft report is on hold until the appropriate performance data from these bridges is available and can be included in the draft.

The remainder of the work on this task will focus on collecting the data from the Taiwan and Turkey earthquakes and incorporating this data into the final report.


Report on performance and behavior of seismically-isolated bridges and buildings in recent earthquakes.

Technical Challenges

No major challenges anticipated.


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