Details:

Creators:
Lamtenzan, Daniel ; Lozev, Mark ; Washer, Glenn
Lamtenzan, Daniel ; Lozev, Mark ; Washer, Glenn Less -
Corporate Contributors:
United States. Federal Highway Administration
Subject/TRT Terms:
[+]
Bridge Substructures Bridge Superstructures Eddy Currents Materials Tests Structural Steel Structural Tests
Publication/ Report Number:
FHWA-RD-00-018
Resource Type:
Research Paper
TRIS Online Accession Number:
00806372
Corporate Publisher:
Turner-Fairbank Highway Research Center
NTL Classification:
NTL-HIGHWAY/ROAD TRANSPORTATION-Bridges and Structures;NTL-HIGHWAY/ROAD TRANSPORTATION-Construction and Maintenance;NTL-HIGHWAY/ROAD TRANSPORTATION-Materials;
Abstract:
This report summarizes research pertaining to the application of the Eddy Current method as a means of crack detection in structural steel members of highway bridges. Eddy currents are induced when an energized coil is placed near the surface of a conductive material. Discontinuities such as cracks disturb the trajectories of the eddy current and thus affect the magnitude and phase of the induced current. These changes can be detected by the probe. Proper probe design can eliminate the effects arising from spatial changes in material properties. Specimens obtained for laboratory use included a calibration block with electro-discharge machining notches with depths of 0.2, 0.5, and 1.0 mm. Five fatigue crack specimens with crack depths of 0.8, 1.0, 1.5, 2.0, and 3.0 mm were also tested. These specimens were used to evaluate voltage and frequency settings and responses. Fatigue crack profiles were tested. These specimens were used to evaluate voltage and frequency settings and responses. Fatigue crack profiles were successfully determined in the specimens. The effect of coatings was also tested in the laboratory using a lead-based coating and several zinc-based coatings. In general, the coatings were found to not significantly interfere with the performance of the method. The Eddy Current method was then used to detect cracks in the pivot girders of the Coleman Bridge over the York River in Yorktown, Virginia. These girders are protected with a zinc-based coating; therefore, other crack detection methods would have required the removal of this coating prior to testing. Eighteen indications were found in the south girder, three of which were cracks. The other 15 were distinguished from cracks by either visual inspection or signal response (for geometric indications or slag inclusions, respectively). Comprehensive studies on the probability of detection can be performed to determine whether or not this method can be widely implemented on steel highway bridges and to determine the reliability of the method. The Eddy Current method is a promising tool for crack detection in steel members of highway bridges.
Format:
PDF
Collection(s):
Federal Highway Administration US Transportation Collection
Main Document Checksum:
[+]
urn:sha256:b769503df84873b1ed0d5033b55e0b4e4e836d28b8350bb6858821b644255e6d
Download URL:
https://rosap.ntl.bts.gov/view/dot/14271/dot_14271_DS1.pdf
File Type:

Supporting Files

• No Additional Files

More +