Scour Program Management

Unknown Foundations: A Marriage in Oregon of Geotechnical and Hydraulic Engineering

  • Edward Foltyn (ODOT)
  • Jan Six


Determining the actual scour susceptibility of bridges with unknown foundations has been a priority of FHWA and the country’s Departments of Transportation for the last ten to fifteen years. After the initial flurry of activity, after the Schoharie Bridge collapse in 1987, analyzing bridges for scour throughout the 1990s, engineers across the country discovered that there were many where the foundations were unknown and therefore could not fully determine the scour susceptibility.

Oregon Department of Transportation (ODOT) took the approach of examining old files to determine whatever information available for bridges. We have over 5600 bridges over water. Through the 1990s, ODOT commissioned scour analyses of 4,000+ of these bridges. In general, these analyses were WSPRO or HEC-RAS analyses based on surveyed cross-sections and designed or record bridge data.

Currently ODOT has about 200 remaining bridges with unknown foundations. Some of these bridges were recently constructed, during the Oregon Transportation Investment Act and we are still receiving final record drawings and design calculations. We have Plans of Action (POAs) for all “Unknown Foundation” bridges and are currently in the process of determining the foundation characteristics for the bridges with higher ADTs. ODOT has contracted with FDH Engineering, Inc. to perform non-destructive testing on our bridges using Dispersive Bending Wave and Parallel Seismic determine thickness of shallow foundations and the lengths of piles.

This presentation will discuss the results of that geotechnical/geophysical testing and where Oregon stands with updating scour analyses for the unknown foundations in Pontis.

How to Cite:

Foltyn, E. & Six, J., (2014) “Unknown Foundations: A Marriage in Oregon of Geotechnical and Hydraulic Engineering”, National Hydraulic Engineering Conference 2014 1(2014).

Rights: Copyright © 2014, Edward Foltyn, and Jan Six

Publisher Notes

  • Panel moderated by Dave Claman, IOWADOT.
  • About the Presenters: Ed. Foltyn, P.E. is the Bridge Hydraulic Engineer for the Oregon Department of Transportation, located in Salem, Oregon since 2012. He is a licensed engineer in Oregon and New Hampshire. Ed has been with ODOT since 2006 where he was a Hydraulic Engineer in Region 1. Ed previously worked as a Research Hydraulic Engineer for the U.S. Army Cold Regions Research and Engineering Laboratory (CRREL) in Hanover, New Hampshire and in the private sector for general civil engineering consultants. Mr. Foltyn received a Bachelor of Science Degree and a Master of Science Degree in Civil Engineering from Clarkson University in Potsdam, New York.

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Published on
21 Aug 2014
Peer Reviewed