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Long-term evaluation of the acoustic emission weld monitor
N DT Abstracts needed which could determine the extent of intemui cracking and the orientation and depth of cracks in reinforced concrete. The system chosen had to be robust and portable and distinguish between cracks, reinforcement and other embedded materials. A literature search using in NDT database revealed a number of possible NDT techniques. Four ultrasonic techniques and an acoustic emission (AE) method were assessed experimentally using standard concrete building block. The ultrasonic techniques met with limited success and the AE tests were useful for source location, Three further NDT techniques were considered for the task, but no experimental assessment was made, namely radar, thermography and electrical continuity. 43049 Miki, C.; Fukazawa, M.; Katoh, M.; Ohune, H. Feasibility study on non-destructive methods for fatigue crack detection in steel bridge members Welding in the World, Vol. 27, Nos. 9/10, pp. 248-266 (1989) The length of two types of small fatigue cracks originating from fillet welds has been evaluated by various non-destructive tests: visual inspection, magnetic particle testing, dye penetrant testing, ultrasonic testing, eddy current testing. The limits of detection have been compared and a relationship has been established between the actual size of the cracks and their estimated size in each case. Finally the influence of a coat of paint on the aptitude of these various methods to detect superficial fatigue cracks has been studied. The optimal process conditions have equally been defined for control techniques. 42662 McCurdy,M. Ultrasonic inspection of pin assemblies in bridges Materials Evaluation, Vol. 47, No. 12, pp. 1340-1341 (Dec. 1989) Studies show that many of the nation's bridges are in dire need of major repairs. Until recently, only visual inspection was commonly used to examine critical components. Ultrasonics and other nondestructive evaluation methods are being instituted and will play a major role in future bridge inspections. This article describes a recent application of ultrasonic nondestructive testing to examine pin and hanger assemblies. In an effort to detect a fracture before total failure occurs, the US Federal Highway Administration (FHWA) has amended the National Bridge Inspection Standard. The revision, mandates that all fracture-critical members be inspected using ultrasonic testing. Straight- and angle-beam tests are performed to investigate thoroughly a pin's integrity. The straight-beam test transmits a beam of sound from one end of the pin to the opposite end, looking for fractures that occur where the hangar plates are seated. The angle-beam test is used to enhance the reflection of outside- diameter cracks and to avoid obstacles, such as cotter pin holes. Angle-beam inspection can reveal small cracking or deterioration of the wall due to corrosion. 42447 Brophy,J.W. Automated imaging system for bridge inspection. Executive summary Sigma Research, Inc., Redmond (United States), PB89-134571, FHWA/RD- 87/089, 12 pp. (May 1987) The report describes the design, operation, and capabifities of the ultrasonic imaging system developed for FHWA. The system uses cemputerized data acquisition and a lightweight scanner to obtain color coded images of defects in metal bridge components. Several types of images are obtained, including holographic reconstruction of defects. Defect size, location, and type can be obtained from the images. 41752 Hopwood, T.; Prine, D.W. Acoustic emission monitoring of in-service bridges Kentucky Transportation Research Program, Lexington (United States), PB89-113666/GAR, 61 pp. (Aug. 1987) An experimental acoustic emission (AE) device, the GARD Acoustic Emission Weld Monitor (AEWM), has been field tested on six bridges during the study. The device was evaluated to determine if it could detect fatigue-crack growth on in-service steel bridges. The device rejects high background noise rates typical of bridges and detects and locates AE activity from known defects such as cracks and subsurface flaws. The AEWM functioned properly in every field test to which it was applied. The device has demonstrated capability to perform AE tests on in-service bridges. It may be used to detect hidden defects or to assist in making repair decisions concerning detected discontinuities. The AEWM and AE testing have the potential for low- cost inspection of critical bridge members. 41665 Hoyle,R~].; Rutherford, P.S. Stress wave inspection of bridge timbers and decking Washington State University, Pullman (United States), PB89l13633/GAR, 168 pp. (Jul. 1987) The report is designed to provide information to guide inspectors of
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wood highway structures in the use of stress wave inspection technology. It explains the methods and insmunents used to measure the velocity of sU~ss waves (sound) in wood. The characteristic behavior of sound waves in wood of various species, moisture content, preservative treaunent and infection by wood destroying organisms is described. The important effects of the anatomy of wood and the orientation of grain and annual rings to the wave path are discussed to aid in the interpretation of measurements. Characteristics of the instrumentation essential to its calibration are explained and instruction is provided in the appropriate use of these tools. 41556 Hopwood, T.; Oka, V.G.; Deen, R.C. Reliability assessment of high.risk steel bridges by nondestructive test methods Kentucky Transportation Research Program, Lexington (United States), PB 89-117717/GAR, 92 pp. (Oct. 1987) Fatigue-crack related failures of high-risk steel bridges may be prevented through application of nondestructive tests (NDT). Economical reliability assessment of those structures requires application of a suitable NDT method; testing of fatigue-susceptible members, and periodic retests of those members to preclude problems with growing or previously undetected flaws. Six conventional NDT techniques were tested in the laboratory using butt-weld configured specimens. Those NDT methods were, visual inspection, magnetic particle testing, dye-peneWant testing, flnorescuntenhanced surface testing, eddy-current testing, and ultrasonic testing. The other NDT methods provided better crack-detection capabilities than visual inspection. Visual inspections by different personnel produced low detection rates. Tests using the fluorescent magnetic-particle method missed several indications because of marginal test conditions. The other NDT methods detected all cracks. 41533
Hopwood, T.
Long-term evaluation of the acoustic emission weld monitor Kentucky Transportation Research Program, Lexington, (United States), PB89-122642/GAR, pp. 165 (Feb. 1988) The Kentucky Transportation Research Program conducted an extended 10- month evaluation of the Acoustic emission weld monitor (AEWM) in a bridge fabrication shop. That device was used to detect welding flaws during typical production of butt-welds on flanges and webs used in steel bridges. A total of 153 welds were monitored. AEWM test results were compared with visual inspection and double-blind results of conventional nondestructive testing routinely conducted on the welds. The AEWM did not miss any flaws detected visually or by nondestructive testing. Three AEWM flaw indications were confirmed by conventional nondesmlctive testing (radiography). The AEWM has shown the sensitivity to detect AWS code-rejectabie defects. Due to the success of the unit in detecting flaws, further development is warranted. 41338 Hopwood,T.; Prine, D.W. Acoustic emission monitoring of in-service bridges Kentucky Transportation Research Program, Lexington (United States), PB88-244231/GAR, 61 pp. (Aug. 1987) An experimental acoustic emission (AE) device, the Acoustic Emission Weld Monitor (AEWM), has been field tested on six bridges during the ~tudy. In addition, the device was used to test three other bridges under separate contracts from state highway agencies. The device was evaluated to determine if it could detect fatigue-crack growth on in- service steel bridges. The device rejects high background noise rates typical of bridges and detects and locates AE activity from known defects such as cracks and subsurface flaws. The AEWlVlfunctioned properly in every field test situation to which it was applied. The device has demonstrated capability to perform AE tests on inservice bridges. It may be used to detect hidden defects or to assist in making repair decisions concerning detected discontinuities. The AEWM and AE testing have the potential for low-cost inspection of critical bridge members. 38741 A vasthi, A.S.; Drake, R~L.;Le, H.Q. Nondestructive, in-place inspection of cable stays for the Mississippi River Bddge at Luling, Louisiana Tulane University, New Orleans, Louisiana (United States), PB88-114392, 55 pp. (Jun. 1986) Not held at Harwell The report concerns a proposed technique for nondestructive inspection of cable stays for a cable-stayad bridge at Luting, Louisiana. The method proposed used acoustic transmission through the steel cables. The laboratory results shown establish the apparent feasibility of the method. Field measurement at the bridge from both ends of a single cable indicate that the cable is free of major faults. The method is not yet considered for practical application because of diffculties encountered in the field. These difficulties are explained in the report. Recommendations are LAde to improve the practicality of the proposed method.
394
wood highway structures in the use of stress wave inspection technology. It explains the methods and insmunents used to measure the velocity of sU~ss waves (sound) in wood. The characteristic behavior of sound waves in wood of various species, moisture content, preservative treaunent and infection by wood destroying organisms is described. The important effects of the anatomy of wood and the orientation of grain and annual rings to the wave path are discussed to aid in the interpretation of measurements. Characteristics of the instrumentation essential to its calibration are explained and instruction is provided in the appropriate use of these tools. 41556 Hopwood, T.; Oka, V.G.; Deen, R.C. Reliability assessment of high.risk steel bridges by nondestructive test methods Kentucky Transportation Research Program, Lexington (United States), PB 89-117717/GAR, 92 pp. (Oct. 1987) Fatigue-crack related failures of high-risk steel bridges may be prevented through application of nondestructive tests (NDT). Economical reliability assessment of those structures requires application of a suitable NDT method; testing of fatigue-susceptible members, and periodic retests of those members to preclude problems with growing or previously undetected flaws. Six conventional NDT techniques were tested in the laboratory using butt-weld configured specimens. Those NDT methods were, visual inspection, magnetic particle testing, dye-peneWant testing, flnorescuntenhanced surface testing, eddy-current testing, and ultrasonic testing. The other NDT methods provided better crack-detection capabilities than visual inspection. Visual inspections by different personnel produced low detection rates. Tests using the fluorescent magnetic-particle method missed several indications because of marginal test conditions. The other NDT methods detected all cracks. 41533
Hopwood, T.
Long-term evaluation of the acoustic emission weld monitor Kentucky Transportation Research Program, Lexington, (United States), PB89-122642/GAR, pp. 165 (Feb. 1988) The Kentucky Transportation Research Program conducted an extended 10- month evaluation of the Acoustic emission weld monitor (AEWM) in a bridge fabrication shop. That device was used to detect welding flaws during typical production of butt-welds on flanges and webs used in steel bridges. A total of 153 welds were monitored. AEWM test results were compared with visual inspection and double-blind results of conventional nondestructive testing routinely conducted on the welds. The AEWM did not miss any flaws detected visually or by nondestructive testing. Three AEWM flaw indications were confirmed by conventional nondesmlctive testing (radiography). The AEWM has shown the sensitivity to detect AWS code-rejectabie defects. Due to the success of the unit in detecting flaws, further development is warranted. 41338 Hopwood,T.; Prine, D.W. Acoustic emission monitoring of in-service bridges Kentucky Transportation Research Program, Lexington (United States), PB88-244231/GAR, 61 pp. (Aug. 1987) An experimental acoustic emission (AE) device, the Acoustic Emission Weld Monitor (AEWM), has been field tested on six bridges during the ~tudy. In addition, the device was used to test three other bridges under separate contracts from state highway agencies. The device was evaluated to determine if it could detect fatigue-crack growth on in- service steel bridges. The device rejects high background noise rates typical of bridges and detects and locates AE activity from known defects such as cracks and subsurface flaws. The AEWlVlfunctioned properly in every field test situation to which it was applied. The device has demonstrated capability to perform AE tests on inservice bridges. It may be used to detect hidden defects or to assist in making repair decisions concerning detected discontinuities. The AEWM and AE testing have the potential for low-cost inspection of critical bridge members. 38741 A vasthi, A.S.; Drake, R~L.;Le, H.Q. Nondestructive, in-place inspection of cable stays for the Mississippi River Bddge at Luling, Louisiana Tulane University, New Orleans, Louisiana (United States), PB88-114392, 55 pp. (Jun. 1986) Not held at Harwell The report concerns a proposed technique for nondestructive inspection of cable stays for a cable-stayad bridge at Luting, Louisiana. The method proposed used acoustic transmission through the steel cables. The laboratory results shown establish the apparent feasibility of the method. Field measurement at the bridge from both ends of a single cable indicate that the cable is free of major faults. The method is not yet considered for practical application because of diffculties encountered in the field. These difficulties are explained in the report. Recommendations are LAde to improve the practicality of the proposed method.