The National Academies

SHRP 2 R06(G) [Completed]

High-Speed Nondestructive Testing Methods for Mapping Voids, Debonding, Delaminations, Moisture, and Other Defects Behind or Within Tunnel Linings

  Project Data
Funds: $1,650,000
Research Agency: Texas A&M
Principal Investigator: Andrew Wimsatt
Effective Date: 9/8/2009
Completion Date: 1/31/2013

Project snapshot. More details below.

(Project Number)
Impact on Practice
Product Status

User’s manual for selecting NDT technologies that can detect defects behind or within tunnel linings. TUNNELCHECK software to support integration of ground-penetrating radar and video-collected data to identify problem areas in the tunnel more quickly.
Selecting the best method for inspecting tunnels linings can not only add life to the structure, it can also reduce disruptive detours and lane closures. Practitioners can use the Guide to select NDT technologies that improve inspection and detection and reduce traffic disruption.
This technology has been piloted in tunnels in Colorado and Texas, and in the Chesapeake Bay area of Virginia. The final report is available on the following page.  

Staff Responsibility: Monica Starnes

Because tunnels typically service high-volume traffic and operate in aggressive environments, keeping tunnels open during inspection and minimizing tunnel closures and user delays must be carefully balanced with the need to conduct detailed inspections that ensure the safety of drivers. Nondestructive testing (NDT) technologies have the potential to achieve this balance.

This project had five objectives:
     1. To identify NDT technologies for evaluating the condition of various types of tunnel linings and tunnel lining finishes;
     2. To evaluate the applicability, accuracy, precision, repeatability, ease of use, capacity to minimize disruption to vehicular traffic, and implementation and production costs of the identified technologies;
     3. To conduct the required development in hardware or software for those techniques that show potential for technological improvement within the time limitations of this project;
     4. To prove the validity of the selected technologies/techniques for detecting flaws within or verifying conditions of the targeted tunnel components; and
     5. To recommend test procedures and protocols for successfully implementing these techniques.

This research project conducted an investigation of NDT technologies capable of detecting delaminations, voids, and water intrusion—which involved the use of concrete, shotcrete, and steel test specimens. Field validation testing of NDT devices was conducted on tunnels in Colorado; Texas; Virginia; and Helsinki, Finland. This project also investigated the ability of NDT technologies to detect loose tiles and moisture underneath tiles, and it investigated the ability of NDT technologies to measure concrete permeability. The final report documents these activities, and it also recommends test procedures and protocols to successfully implement these techniques.

Project Status: This project is complete.

Product Availability: The final report is available on the following page.

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