U.S. Department of Transportation
Federal Highway Administration
1200 New Jersey Avenue, SE
Washington, DC 20590
202-366-4000


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Nondestructive Evaluation Laboratory

 

Nondestructive Evaluation (NDE) Laboratory Facilities

FAST NDE Laboratory | Specimen Library | NDE Computer Laboratory

 

FAST NDE Laboratory

The Federal Highway Administration’s (FHWA’s) Advanced Sensing Technology (FAST) NDE Laboratory is a world-class facility for the development and testing of NDE technologies. FHWA has recently renovated and upgraded the FAST NDE laboratory to address the growing needs of FHWA and stakeholders with state-of-the-art NDE tools. Some of the technologies researched at the laboratory include: conventional/phased array ultrasonics; conventional/advanced eddy current; acoustic emission; ground penetrating radar; infrared thermography; impact echo; Structural Health Monitoring (SHM) systems; autonomous tools for condition assessment and automated data collection, analysis, interpretation, visualization and data fusion; and both noncontact and remote sensors.

The laboratory has moved to a 9.4- by 8-meter facility (Figure 1 and Figure 2 ) with new equipment and tools, such as a KUKA robotic arm (KR10-R1100 titan) with a payload of 10 Kg to handle test specimens, multiple NDE equipment, such as a phased array ultrasonic testing system for steel component inspection and ground penetrating radar for concrete inspection (see Equipment page for a complete list).

The three-dimensional, computer-generated drawing is a view of the proposed laboratory interior. On the left wall of the image and left half of the back wall are wall-mounted work tables and shelves. On the right wall and right half of the back wall are desks and chairs. Two handcarts are positioned in the middle of the image, along with an armed marked “Cart Storage”. Two additional unidentifiable pieces of equipment are in the mock-up.
Figure 1. Image. Artist’s rendition of the new FAST NDE Laboratory.

The three-dimensional, computer-generated drawing shows the interior of the Laboratory of Figure 1, but from an angle. Work tables on the left rear wall are visible, along with work desks on the right and right rear walls. Two wheeled handcarts are shown, along with several other items of equipment.
Figure 2. Image. Artist’s rendition of the new FAST NDE Laboratory.

 

Specimen Library

An extensive collection of component specimens is constantly being updated to enhance the NDE program. Component specimens include small sections of highway structures (both in pristine conditions and with known defects) that have been removed from in-service bridges or that are manufactured to represent realistic structural components. The collection of component specimens is continually evolving as specimens become available from decommissioned bridges, are purchased from qualified vendors, or are manufactured in the NDE Laboratory. A summary of the specimens currently at the NDE Center is described below.

Concrete Specimens

The lab houses a pair of full-sized (54-inch-tall by 85-foot-long AASHTO girders) prestressed bridge girders that were removed from an active bridge on Maryland I–90. These girders were installed in 1971 and were in service until they were salvaged to be used for full-scale research in a laboratory setting at the Turner-Fairbank Highway Research Center (TFHRC). The girders were placed on four reinforced soil abutments, suspended approximately 10 feet above the ground (Figure 3 ).

Two bridge girders are shown from an angle. The girders are parallel to each other and each girder is positioned on two cinder block pillars. Each girder assembly is approximately ten feet in height. The girders are positioned diagonally in the photo, with the right end in the foreground, and the left end of the girder in the background. A ladder rests on its side in the right portion of the photo, and an 18-wheeler truck can be seen in the right background.
Figure 3. Photograph. Full-size prestressed bridge girders.

Three validation slabs, measuring 4 feet long, 6 feet wide, and 8 inches high, are also available to verify the applicable and promising methods used on girders (Figure 4 ). The validation slabs were constructed with prestressing strands laid lengthwise throughout with known amounts of strand damage artificially created at known locations. Each validation slab has 26 untensioned half-inch 7-wire stands arranged in 3 vertical layers and 15 longitudinal rows. Several different scenarios of damage were created in each slab, including 5 percent, 10 percent, 25 percent, and 100 percent section loss at predetermined locations (Figure 5 ).

The photograph was taken from an oblique overhead angle. Centered in the photograph is a 4-ft long by 6-ft wide recently poured concrete slab. The slab is contained within a rectangular wooden form or mold. Portions of two similar concrete-filled wooden molds can be seen in the right rear portion of the photograph.
Figure 4. Photograph. Validation slabs after pouring.

Three wire strains are positioned horizontally across the photograph. Each strain consists of several smaller strands wound together. The middle wire strand has is marked with two pieces of red tape, and the wire segment between the tape has been shaved halfway through, showing the internal construction of the strand.
Figure 5. Photograph. Artificially created strand damage.

The specimen library also includes a 6-foot long, 8-foot wide, 9-inch high concrete slab with built-in delaminations at predetermined locations used as a blind testbed for NDE technologies (Figure 6 ). Multiple methods are used to create these delaminations, such as embedded cardboard, sandwich concrete plates, and polyethylene sheets, with the purpose of studying applicability and viability of NDE technologies and tools to detect these built-in defects.

A rectangular slab is viewed from an overhead angle. The surface of the slab has been scored with lines forming a grid. The concrete slab is secured to a wooden pallet with wire bands and cardboard has been inserted between the wire bands and the concrete to prevent damage to the slab.
Figure 6. Photograph. Concrete slab with built-in delaminations.

To test the anchorage systems of highway barriers in the laboratory setup, a 12-foot long, 8-foot wide, 8-inch high mockup bridge deck along with concrete barriers are available in the laboratory (Figure 7 through Figure 10 ). The barriers selected were attached to the mockup bridge deck using four #4 and four #6 reinforcing steel bars with different levels of simulated cross-section loss (0, 10 percent, 25 percent, and 50 percent), as shown in Figure 11 .

A rectangular piece of concrete lying flat on a grassy/dirt area is displayed. One third of the concrete piece has a vertical scoring line.
Figure 7. Photograph. Mock bridge deck.

Two 3-ft high concrete barriers are viewed from a side angle. The barriers are parallel and upright with approximately 1 ft of space between their sides. The bottom surfaces of the barriers are in contact with the ground. The barrier in the foreground has suffered damage in its upper left corner and in two locations on its bottom edge. In addition, the left portion of the barrier exhibits severe abrasion.
Figure 8. Photograph. Retired service barrier.

Six concrete barriers of various shapes and sizes are lined up in an upright position on a dirt/gravel patch. The barriers The two front barriers are of similar size and shape, approximately 3-ft tall and 12-ft long. Halfway along the bottom edge of the front barrier, significant chipping damage is displayed. A faint grid pattern can be seen along the length of the barrier.
Figure 9. Photograph. Jersey barrier with delaminations.

Six concrete barriers are viewed from a side angle. The barriers are in and upright, standing position, and are roughly parallel. The three barriers shown from the far right to middle screen are designed with four vertical channels. End fasteners can be seen on two of the three barriers. At the bottom of each channel is a vertical hole that is used to bolt the barrier into place.
Figure 10. Photograph. Barriers with delaminations.

Two concrete barriers are positioned parallel to each other on a concrete slab. The photograph is taken from the end of the barriers viewing down the pathway between the barriers. In the background is a white panel truck. The left barrier is a solid form and is labelled “New Jersey Type”, while the right barrier has four vertical channels to enable bolting down and is labelled “F-Shape Bolt Down’. Metal rods are inserted in the holes within the vertical channels. In addition, each bolt down hole has been labelled starting from the far end of the barrier with 0%, the next one is labelled 10%, the following hole is labelled 25%, and the final hole that is closest to the view is labelled 50%. A piece of wood is supporting the front right corner of the concrete slab.
Figure 11. Photograph. Simulated cross-section loss of rebar at F-shape
bolt-down barrier connection and New Jersey barrier connection.

Steel Specimens

This collection includes samples from steel bridges with different configurations. The specimens have different joint geometries, material thicknesses, coatings, and weld defects. The inventory includes a number of butt-weld specimens with Complete Joint Penetration (CJP) groove welds, butt-welds with well-bonded bridge coatings, T-joint specimens with fillet weld butt joints, and re-entrant corner joint specimens with fillet welds. Engineered cracks are embedded in these specimens and a variety of crack geometries are represented.

Bare Metal Steel Specimens

Figure 12 through Figure 16 show each of the specimen’s geometries. The specimen base metal complies with ASTM A709 material specifications. All fabrication and welding was performed in accordance with the American Welding Society (AWS) D1.5 Bridge Welding Code.

The photograph consists of a large metal surface showing two smaller rectangular metal plates that have been welded in place. The longer metal plate is horizontally positioned in the photograph, with the shorter metal plate placed perpendicularly. The welds joining the edges of the smaller plate to the rectangular surface are clearly visible.
Figure 12. Photograph. Typical T-Joint specimen with fillet welds.

The photograph consists of a large metal surface showing two smaller rectangular metal plates that have been welded in place. The shorter metal plate is horizontally positioned in the photograph, with the longer metal plate placed perpendicularly. There is a significant gap between the two perpendicular pieces. The welds joining the edges of the larger plate to the rectangular surface are clearly visible.
Figure 13. Photograph. Typical T-Joint specimen with fillet welds.

The photograph is an overhead view of two rectangular plates joined with a butt-weld to create a larger rectangular plate. Some corrosion is present in the welded plates. The specimen is labeled NDE-10.
Figure 14. Photograph. Typical butt joint specimen with CJP groove welds.

The photograph is an angled overhead view of two polished rectangular plates joined with a T-weld. The larger plate is resting flat on a surface and the smaller plate is perpendicular. The specimen is labeled NDE-13.
Figure 15. Photograph. Typical T-Joint specimen with fillet welds.

The photograph is an angled overhead view of three welded rectangular plates. The larger plate is resting flat on a surface, and the two smaller plates are perpendicular to each other and the larger base plate. The specimen is labeled NDE-21.
Figure 16. Typical Reentrant Corner Joint specimen with fillet welds.

Coated Steel Specimens

The purpose of the coated specimen shown in Figure 17  was to evaluate the effect of typical bridge coatings on measurements. The specimen was coated with a typical three-coat bridge system. The three-coat bridge system comprises of an organic zinc-rich primer, an epoxy intermediate, and polyurethane topcoat applied by KTA-Tator. This coating was a mixture of KTA-Tator’s Carbozinc® 859; Carboguard® 893SG with optional (LT) cure, and Carbothane 133 LH products. This coating system is a well-established and commonly used system by DOTs in the U.S.

The photograph is a two-dimensional view of a painted rectangular metal plate. A circle is marked within a small etched rectangle in the approximate center of the plate. The specimen is labeled NDE-8.
Figure 17. Photograph. Typical coated specimen.

 

NDE Computer Laboratory

The computing capability of the NDE Laboratory is composed of two individual multiprocessor units that are connected through the Internet II national network to the cluster supercomputer in the Transportation Research and Analysis Computing Center (TRACC) located in the Argonne National Laboratory (ANL) in Lemont, IL. The computing machine is loaded with a massive parallel processing (MPP) version of a finite element program called LS-DYNA. This program is used for finite element modeling, analysis, and simulation of complex real-world problems. Research using these computing facilities has been focused on advanced computing and large-scale dynamic simulations of highway bridges. The work includes large bridge model dynamic response analyses, simulations of traffic flow loads, wind-rain loads for cable-stayed bridges, meshless computation for crack detections in highway structures, nonlinear dynamics simulations for chaos control of cable-stayed bridge vibrations, as well as data analyses covering a wide range of advanced NDE tasks.

 

Federal Highway Administration | 1200 New Jersey Avenue, SE | Washington, DC 20590 | 202-366-4000
Turner-Fairbank Highway Research Center | 6300 Georgetown Pike | McLean, VA | 22101