USGS Home
Contact USGS
Search USGS

Prepared in cooperation with the Maine Department of Transportation

Comparison of Observed and Predicted Abutment Scour at Selected Bridges
in Maine

By Pamela J. Lombard and Glenn A. Hodgkins

This report is available as a printed product and in PDF Format (1.87 MB), Report Cover (46.2 KB)

Abstract

Maximum abutment-scour depths predicted with five different methods were compared to maximum abutment-scour depths observed at 100 abutments at 50 bridge sites in Maine with a median bridge age of 66 years. Prediction methods included the Froehlich/Hire method, the Sturm method, and the Maryland method published in Federal Highway Administration Hydraulic Engineering Circular 18 (HEC-18); the Melville method; and envelope curves. No correlation was found between scour calculated using any of the prediction methods and observed scour. Abutment scour observed in the field ranged from 0 to 6.8 feet, with an average observed scour of less than 1.0 foot. Fifteen of the 50 bridge sites had no observable scour. Equations frequently overpredicted scour by an order of magnitude and in some cases by two orders of magnitude. The equations also underpredicted scour 4 to 14 percent of the time.

If you have Adobe^® Acrobat^® or Adobe^® Acrobat^® Reader^® installed on your computer, you may view and print the PDF version of this report. Acrobat Reader, is a free download from Adobe Systems, Inc. Users with disabilities can view information concerning accessibility at access.Adobe.com.

Suggested citation: Lombard, P.J., and Hodgkins, G.A., 2008, Comparison of observed and predicted abutment scour at selected bridges in Maine: U.S. Geological Survey Scientific Investigations Report 2008–5099, 23 p., available only online at http://pubs.usgs.gov/sir/2008/5099.

For more information please contact:

Director, USGS Maine Water Science Center
196 Whitten Road
Augusta, Maine 04330
Telephone: (207) 622-8201

Email: dc_me@usgs.gov

Web site: http://me.water.usgs.gov