The National Academies

NCHRP 10-30(3) [Completed]

Nondestructive Methods for Field Inspection of Embedded or Encased High Strength Steel Rods and Cables

  Project Data
Funds: $400,000
Research Agency: University of Manchester
Principal Investigator: Dr. D. Gareth John and Prof. F. M. Burdekin
Effective Date: 7/1/1987
Completion Date: 4/30/1991

There is growing concern about corrosion, deterioration, and structural integrity of steel components used in cable-stayed bridges and segmentally constructed concrete bridges when these components are placed in ducts or embedded in concrete and thereby not accessible for visual inspection and evaluation. To make informed decisions on maintenance and rehabilitation of bridge members, engineers need to know the rate at which deterioration or distress is occurring and the extent of damage that has already taken place. Various nondestructive inspection (NDI) methods that could be used to evaluate the condition of these steel components should be assessed, and one or more practical systems for on-site inspection and evaluation of steel components in bridge members should be developed for field use.

After reviewing the results of Projects 10-30(1) and 10-30(2), the University of Manchester Institute of Science and Technology's proposed plan for a Phase II was chosen by the NCHRP. Accordingly, the objective of Phase II was to experimentally evaluate the chosen methods using realistic bridge components.

Research focused on the development of an ultrasonic technique to interrogate the condition of prestressing steel in concrete. The research has thoroughly explored various options and is now complete. A prototype ultrasonic device employing "rolling transducers" was developed; however, the device, in the opinion of the NCHRP, has very limited capabilities rendering it impractical for actual field applications. Nevertheless, the research experiments are exceptionally well documented and will be a relevant source for future forays on this subject.

Research Results Digest No. 188, "Ultrasonic Nondestructive Testing for Deterioration of High-Strength Steel Components Embedded in Concrete," summarizes the research effort. The agency's complete final report was also distributed to all state DOTs.

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