Weak-link analysis for seismic retrofit of bridge structures

摘要

This paper investigates the seismic retrofit strategy of a "critical" bridge in New York City. Site response spectra for 500-year and 2500-year earthquakes were developed in accordance with the New York City Department of Transportation (NYCDOT) new seismic design criteria. The analysis is based on softening the structure, by introducing a weak-link concept, in which guide angles yield under the 2500-year earthquake, shifting the fundamental frequency in the lower region of the response spectrum. As a part of this softening approach, six elastomeric bearings were incorporated into the structural system. This results in reducing the seismic forces demand on the substructure, thus eliminating the need for footings and piles retrofit.