Seismic Isolation of Highway Bridges

Keywords: Seismic isolation.  Bridges.  Retrofitting.  United States.  Seismic protection.  Seismic response.  Structural performance.  Elastomeric isolators.  Sliding isolators.  Highway infrastructure.  Seismic designs.  Lead rubber bearings (LRB).  Friction-pendulum isolator.  Eradiquake isolator.  American Association of State Highway Transportation Officials (AASHTO).  Energy dissipation.  Rigidity.

Abstract: More than 200 bridges have been designed or retrofitted in the United States using seismic isolation in the last 20 years, and more than a thousand bridges around the world now use this cost-effective technique for seismic protection.  Intended to supplement AASHTO’s Guide Specifications for Seismic Isolation Design (1999), this manual presents the principles of isolation for bridges, develops step-by-step methods of analysis, explains material and design issues for elastomeric and sliding isolators, and gives detailed examples of their application to standard highway bridges.  Design guidance is given for the lead-rubber isolator, the friction-pendulum isolator, and the Eradiquake isolator, all of which are found in use today in the United States.  Guidance on the development of test specifications for these isolators is also given.