Transportation Infrastructure:

The Nation's Highway Bridges Remain at Risk From Earthquakes

RCED-92-59: Published: Jan 23, 1992. Publicly Released: Jan 23, 1992.

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John H. Anderson, Jr
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Pursuant to a congressional request, GAO reviewed the threat that earthquakes pose to the nation's bridges, focusing on: (1) which states had areas where bridges could be damaged by moderate- to high-intensity earthquakes; (2) the Federal Highway Administration (FHwA) actions to identify and correct seismic-related bridge deficiencies; and (3) FHwA actions to assist states in addressing seismic deficiencies in bridges.

GAO found that: (1) 31 states have bridges that are at risk of damage from moderate- to high-intensity earthquakes; (2) although FHwA has encouraged states to identify and retrofit existing bridges on important defense and evacuation routes and main commuter and commerce routes, states have made limited progress in identifying and correcting seismic-related bridge deficiencies; (3) 8 of the 26 surveyed states at seismic risk stated that they had identified vulnerable bridges and had retrofitted, or were in the process of retrofitting, less than 2 percent of those bridges; (4) states that had made limited attempts to identify and retrofit at-risk bridges cited such reasons for their reluctance to do so as limited funding, a lack of technical retrofit information, and a belief that their states were not at a risk for earthquake damage; (5) although FHwA required states to annually report on their bridges' overall structural condition, it did not require states to identify bridges subject to seismic forces; and (6) because the degree of seismic risk varied among states, FHwA primarily facilitated seismic efforts by providing states with procedural guidance, training, and assistance in state seismic research efforts, but states believed that they needed additional FHwA assistance because they lacked experience and expertise in addressing seismic bridge deficiencies.

Recommendations for Executive Action

  1. Status: Closed - Not Implemented

    Comments: The Department of Transportation (DOT) maintains that its current actions are sufficient and that adding data to the National Bridge I inventory is not necessary to accomplish the goal of promoting seismic safety.

    Recommendation: The Secretary of Transportation should direct the Administrator, FHwA, to require states in areas of moderate to high seismic risk to identify bridges vulnerable to earthquake damage in conjunction with their routine bridge inspections and report this information on seismically vulnerable bridges to FHwA for inclusion in the National Bridge Inventory.

    Agency Affected: Department of Transportation

  2. Status: Closed - Implemented

    Comments: A course on seismic design of foundations is currently online, while a second course on how to apply American Association of State Highway and Transportation Officials seismic specifications has incurred funding delays but is now being finalized. In addition, a new manual on seismic guidelines was published in May 1995 under publication FHWA-RD-94-052. Finally, a major seismic research project is still being conducted at the National Center for Earthquake Engineering Research in Buffalo, New York.

    Recommendation: The Secretary of Transportation should direct the Administrator, FHwA, to expand the range of seismic-related training.

    Agency Affected: Department of Transportation

  3. Status: Closed - Implemented

    Comments: FHwA has contracted with the National Center for Earthquake Engineering Research in Buffalo, NY, to develop improved procedures for disseminating information on seismic research to the highway community, and work is under way. In addition, FHwA is disseminating lessons learned from recent California earthquakes to all states and is keeping states apprised of the status of all ongoing seismic-related research.

    Recommendation: The Secretary of Transportation should direct the Administrator, FHwA, to consolidate and disseminate bridge-related seismic information and research to states.

    Agency Affected: Department of Transportation


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