Preparing for the unexpected in New York State: Development of an Earthquake Response Plan to assess potential bridge damage

Recent natural extreme events have heightened awareness of the vulnerability of highway infrastructure. Thus, even though New York State is one of the regions with low to moderate seismic activity, realizing that bridge infrastructure may be severely impacted if NYS experiences a low probability medium to severe intensity earthquake, the NYS Department of Transportation (NYSDOT) is developing an earthquake response plan for managing bridge inspections in the aftermath of such an event. This paper will give a brief synopsis of the guidelines under development. It is anticipated that regional NYSDOT engineers will rely on USGS Earthquake Notification System (ENS) for earthquake notifications when their area experiences an earthquake of a magnitude equal to or greater than M3.5. The Earthquake Response Plan calls for an immediate preliminary bridge damage assessment along priority routes to determine if they are safe for use. Subsequent special post-earthquake bridge inspections, conducted by professional engineers, will be prioritized based on their proximity to the epicenter, criticality of the structure, seismic vulnerability of its details, and consequence of failure. The planned level of response will be in proportion to the severity of ground shaking by using a larger radius of concern, level of effort, and the number of bridges to be inspected for increasingly stronger earthquakes.