Seismic Geotechnical Investigations of Bridges in New York City

Seismic vulnerability assessment of a critical bridge is a major undertaking. Such an investigation may lead to requirements with respect to seismic retrofitting of an existing bridge or enhancement of the design of a new bridge, often at considerable cost. A safe and cost-effective new design or retrofit of a bridge requires the application of realistic evaluations at every step of the seismic analysis, in which geotechnical earthquake engineering should play an important role. Soil and site conditions can have important effects on not only the earthquake motions but also on the dynamic response of the soil-foundation-bridge system. This paper presents case history analyses that demonstrate the importance of geotechnical earthquake engineering in seismic safety evaluation of bridges in New York City