LRFD-Based Analysis and Design Procedures for Bridge Bearings and Seismic Isolators

Keywords: Load and resistance factor design (LRFD) framework.  Seismic designs.  Bridges.  Seismic isolation systems.  Polytetraflouroethylene (PTFE) spherical bearings.  Elastomeric bearings.  California.

Abstract: This report describes the development and application of analysis and design specifications for bridge bearings and seismic isolators that (a) are based on load and resistance factor design (LRFD) framework; (b) are based on similar fundamental principles, which include the latest developments and understanding of behavior; and (c) are applicable through the same procedures regardless of whether the application is for seismic-isolated or conventional bridges.  Examples are presented of design of conventional elastomeric and polytetraflouroethylene (PTFE) spherical bearings and three examples of detailed design and analysis of the seismic isolation system of a bridge located in California utilizing lead-rubber, single Friction Pendulum and triple Friction Pendulum isolators.  The seismic isolation design examples utilize the latest definition of seismic hazard in California and intent to serve as a guide to application of the technology to serve as a guide to application of the technology to bridges in California.