U.S. Department of Transportation
Federal Highway Administration
|Subject:||ACTION: Compliance with the National Bridge Inspection Standards; Plan of Action for Scour Critical Bridges||Date:||July 24, 2003|
|From:||/s/ Original signed by:
King W. Gee,
Associate Administrator for Infrastructure
|Reply to Attn. of:||HIBT-20|
|To:||Directors of Field Services
During the past 15 years, the Federal Highway Administration (FHWA) and State departments of transportation (DOTs) have committed resources to coordinate and conduct bridge scour evaluations of the 484,546 bridges over waterways. Thanks to this commitment, 93 percent of these bridges have been evaluated as reported by State DOTs in their April 15, 2003, biannual scour report. We appreciate the commitment of your staff and State DOTs towards the National Bridge Scour Evaluation (NBSE) Program and encourage you to continue working with your State DOTs to complete all bridge scour evaluations.
State DOTs have identified 26,472 bridges over waterways to be scour critical through the conduct of evaluations following the revised guidance for coding Item 113 of the FHWA Recording and Coding Guide, which was implemented in Mr. James D. Cooper's April 27, 2001, memorandum. Now we need to focus on the next phase of the program, which deals with bridges identified as scour critical. Since the beginning of the program, the FHWA has recommended bridge owners to develop a plan of action (POA) for each bridge identified as scour critical. However, we believe that only a few State DOTs have been actively developing and implementing POAs for their bridges identified as scour critical. We would like to emphasize that the NBSE Program has been built upon our belief that providing safety to the public users is our number one priority. As such, we strongly believe that POAs should be adopted to scour critical bridges with specific instructions and measures that would prevent a catastrophic failure of a bridge.
Guidance for developing a POA for a scour critical bridge has been expanded in the second edition of the FHWA Hydraulic Engineering Circular No. 23 (HEC-23), titled "Bridge Scour and Stream Stability Countermeasures" dated March 2001. In addition, the Office of Bridge Technology, jointly with the Office of Research and Development assembled material on strategies for developing a POA. This material was first presented at the January 2002 Plan of Action workshop sponsored by the Transportation Research Board's A2A03 Committee on Hydrology, Hydraulics and Water Quality in Washington, D.C. (see attached). This material, based on the guidance presented in HEC-23, includes important elements that have already been applied by a few State DOTs on their POAs, and a generic POA developed by FHWA.
Please share this material with your corresponding State DOT management officials and encourage them to use as appropriate in developing and implementing a POA for their scour critical bridges. This material is also available in the Office of Bridge Technology's website at http://www.fhwa.dot.gov/engineering/hydraulics/conferences/sctrb02/sctrb.htm.
The FHWA hydraulics engineers in Headquarters and the Resource Center are available upon request to work with your staff and the appropriate staff within your corresponding State DOT to progress this important phase of the NBSE Program.
Should you have any questions please do not hesitate to contact Mr. Jorge E. Pagán-Ortiz, Leader of the FHWA National Hydraulics Team, at (202) 366-4604.