NCHRP 21-05(2) [Completed]
Unknown Subsurface Bridge Foundation Testing
| Project Data
||Olson Engineering, Inc.|
||Larry D. Olson|
Background: There are approximately 580,000 highway bridges in the National Bridge Inventory. For a large number of older non-federal-aid bridges, and to a lesser extent federal-aid bridges, there are no design or as-built bridge plans, and there is little or no information available to document the type, depth, geometry, or materials incorporated into the foundations.
The Federal Highway Administration now requires state transportation departments to screen and evaluate all bridges over rivers or streams to determine their susceptibility to scour; however, information on bridge foundations is necessary to perform such evaluations. Similar information on foundations is also needed for seismic evaluation of bridges.
Research is needed to develop practical methods and functional equipment to determine subsurface bridge foundation characteristics such as type, depth, geometry, and materials when little or no information is available.
Objective: The objective of this project is to further develop, instrument, and fully validate the surface and borehole nondestructive testing (NDT) technologies with the greatest application range as determined in NCHRP Project 21-5, "Determination of Unknown Subsurface Bridge Foundations."
Tasks: Research will include the following tasks: (1) Evaluate in greater detail those methods that were identified in the NCHRP Project 21-5 research as having the most promise of solving the unknown depth-of-bridge-foundation problem, including, but not limited to Ultraseismic, Parallel Seismic, Spectral Analysis of Surface Wave, and Induction Field testing, and conduct initial "blind" NDT studies of 20 bridge sites with known foundations to determine the accuracy of testing methods. (2) Develop prototype Ultraseismic, Parallel Seismic, and Induction Field instrument systems. (3) Submit an interim report summarizing the results of the studies, evaluations, and systems developed in Tasks 1 and 2, and provide an updated work plan for a semiblind demonstration evaluation of 20 bridge sites in 5 different regions. (4) Upon NCHRP approval, execute said semiblind demonstration study. (5) Submit a final report documenting all research findings, the results of the demonstration studies, and other DOT case histories.
Status: The project is complete. The results of Project 21-05(02) will not be published in the NCHRP report series. Instead the research results are being released only as an unedited final report and accompanying guideline document completed by the principal investigator, Larry Olson, of Olson Engineering. The NCHRP feels that even though the research results from Project 21-05(02) are interesting, they are inconclusive and are not of sufficient accuracy and reliability to be implemented in normal practice at this time by state DOTs.
Product Availability: A summary of results from NCHRP Project 21-5 was published as NCHRP Research Results Digest 213:Nondestructive Testing of Unknown Subsurface Bridge Foundations--Results of NCHRP Project 21-5.
The unedited final report for NCHRP Project 21-5(02) as prepared by Olson Engineering is available here.