Seismic Vulnerability of the Highway System

Task D1-1: Performance Review of Seismically-Isolated Structures
Subject Area: Earthquake Protective Systems

Principal Investigator(s) and Institution(s)
George C. Lee, University at Buffalo

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. Included in this will be a review of the seismic performance of structures with isolation bearings during the Northridge and Kobe earthquakes.

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 reasons for this confusion may relate to the nature of ground motion rather than the isolators themselves. These issues need to be resolved.

This task will therefore focus on bridge performance during recent earthquakes. Relevant information on isolated buildings will also be reviewed. This will include not only a review of published papers and reports, but also discussions with authors, designers, and bridge owners who may have relevant information on the design and performance of seismically-isolated structures (e.g. Mayes, Sheppard, Nagarajiah, Watanabe, Sugiura, PWRI, etc.).

Anticipated Start Date and Duration
January 1, 1999 - 12 months