Accessible and Cost-Effective Approach for Seismic Retrofit of Highway Bridges

This paper presents an accessible and cost effective seismic retrofit strategy for a four continuous span bridge in New York City. Due to its importance, the bridge has been classified as "critical" from a seismic point of view. Seismic motion input is based on site response spectra for 500-year and 2500-year earthquakes. A new system of elastomeric bearings is incorporated into the structure. This system is designed to yield at a certain threshold of seismic movement providing a fuse-type action, thus softening the system and reducing the seismic forces transmitted to the substructure. After the seismic event, the yielded part is replaced without need for jacking or replacement of the bearing system.