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February 3, 2016
SHRP-2 Research: VDOT Bridges
February 3, 2017

SHRP-2 Research: Liberty & Armstrong Tunnel

SHRP-2 Nondestructive Testing for Tunnel Linings (RO6G) Showcase Event in Pittsburgh, PA

Penetradar participated in the SHRP-2 Nondestructive Testing (NDT) for Tunnel Linings (RO6G) Showcase sponsored by PennDOT, in Pittsburgh, PA. Anthony Alongi, President of Penetradar Corporation, presented our results, which was then followed by a live demonstration of ground penetrating radar (GPR) technology in the Liberty Tunnel. DOT’s and Tunnel owners from across the USA were present for the showcase to learn about state-of-the-art NDT methods for tunnel evaluation, which in addition to GPR also included High Resolution Imaging (HRI) and Infrared Thermography (IRT).

Penetradar presented their findings from research and demonstrated equipment in the field.


Our results consisted of high resolution images of the liner, infrared thermal images, GPR measurement of attenuation and dielectric constants, and identification of areas of deteriorated liner, voids and moisture intrusion. The combination of these methods provide an effective means of identifying specific areas in need of repair and determining the overall condition of tunnel liners. Core samples, soundings and petrographic analysis showed results consistent with the GPR analysis, and when comparing GPR delamination results with ground truth measurements, GPR detected 75% of the known delamination locations and 90% of the sound areas of concrete.


Examples of the NDT results compared to the manual inspection (ground truth) and plan view mappings.


Our presentation and demonstration of NDT methods identified by SHRP R06G for tunnel evaluation showed that high-speed, non-destructive methods such as GPR, IRT and HRI can provide the critical information needed by engineers for design and maintenance in a cost effective and non-intrusive manner.

Click above to view local media coverage of the NDT demonstration.


Contact us for more information on non-destructive tunnel liner inspections or to find out whether this technology may be suitable in your application.

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