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Acoustic emission and ultrasonic testing of concrete structures
N DT Abstracts from various sensors in order to achieve greater nose rejection. Two areas are monitored, one area near the fatigue crack tip and the other in the region of probable propagation. The experimental results are as follows: when crack propagates, the AE signal is stronger in the crack tip area than in other areas. It is thus possible to detect and compare fatigue crack growth from two different regions of the sample. This system also removed noise effectively.
Plecnik, J.M.; Henriquez, O.E. Acoustic emissions on complex composite bridge
55659
deck structures Advanced Materials: Expanding the Horizons. 25th International SAMPE Technical Conference, Philadelphia, Pennsylvania (United States), 26-28 Oct. 1993. Vol. 25, pp. 759-770. Edited by R. Trabocco and T. Lynch, SAMPE (1993) This program studies the performance of an innovative modular fiberglass composite bridge deck system. Both the commercial AASHTO HS20-44 truck load and the Alternative Military load were applied to composite deck specimens in a series of fatigue tests. Throughout these tests, performance of the specimens was monitored by using the acoustic emissions (AE). It was found that AE activity during the first fatigue cycles can be used to predict whether or not the deck is appropriate to withstand several million truck load cycles. The study was performed on two 213 cm (7 ft.) wide deck specimens. Test setups simulated two different types of mechanical connections necessary for the modular bridge deck system. Results indicate the composite deck is adequate to withstand the design loads.
Zhwo, Z.; Haldar, A.; Breen, F L. Fatigue-reliability updating through inspections of steel bridges 55473
Journal of Structural Engineering, Vol. 120, No. 5, pp. 1624-1650 (May 1994) The sensitivity and capability of inspection mathods, including ultrasonic inspection, are investigated. The detection events are classified into three cases, no crack detection, crack detection but without size measurement, and crack detection with the crack-size measurement. Using the information from k inspections, the distributions of the basic random variables and the corresponding reliability index are updated. It is concluded that the inspection results can be used to maintain the fatigue-damage integrity of steel bridges.
55314 Hu, K.K.; Gattani, S3V.; Russell, E.R.; Swartz, S.E. An inexpensive pavement condition monitoring system International Conference on Nondestructive Testing of Concrete in the Infrastructure, Dearborn, Michigan (United States), 9-11 Jun. 1993. pp. 451-466. Society for Experimental Mechanics, Inc., (1993) ISBN 10912053429 A concept is explored wherein a portable, person-operated system with modest capabilities and cost is used. This has the ability to map surface irregularities - especially rutting/profiles and surface defects - spalling, cracking, holes in an automated fashion. Data are obtained using an ultrasonic transducer and a video still camera. These are stored digitally to be reconstructed later and merged spatially into a map using appropriate imaging enhancement of pavement distress features of interest. In its present form, the device is best suited for analyzing bridge decks. This will allow the sponsor to assess quickly the condition of a bridge deck and to keep record of changes over time in a convenient form on a video tape and/or disk. 55057 Bligh, R.P.; Nakirekanti, S.; Bray, D.E.; James, R.W. Evaluation of NDE techniques for detecting grout defects in cable stays Materials Evaluation, Vol. 52, No. 4, pp. 508-514 (Apr. 1994) Problems with corrosion of steel strands in grouted bridge cable stays have raised concern about the integrity of the grout layer protecting the strands. Bleed water may accumulate in the grout layer if voids or bubbles are trapped during the grouting process, leading to localized corrosion of the cables. A research study has been undertaken to assess various nondestructive evaluation (NDE) methods for inspection of this grout layer. Methods studied include ultrasonics, X-ray radiography, computed tomography, and neutron radiography. Representative models of grouted cable stays were prepared with manufactured defects to investigate the feasibility of these techniques.
390
Declerck, P. Bibliographic study of georadar principles, applications, advantages, and inconvenience. (In French, English abstract) 54877
Centre de Recherches Routieres, Brussels (Belgium), N9318993/4/GAR, 53pp. (1991) The literature survey reviews some 25 years of reporting on attempts to use electromagnetic pulses for nondestructive material testing. The higher the frequency, the higher the resolution and the smaller the depth of penetration. Special antennas are required for specific applications such as the detection of linear structures (pipes, cables) or the investigation of walls and bridge decks. Radar is a fast, high- yield and continuous method of surveying and the waves are not stopped by voids or cracks, unlike acoustic waves or seismic vibrations. Radar operates well in poorly conducting materials and less well in wet or clayey soils. 54628 Forde, M.C.; McCavitt, N. Sonic NDT and radar testing of masonry British Journal of Non-destructive Testing, Vol. 36, No. 3, pp. 140145,147 (Mar. 1994) The various methods of non-destructively testing masonry are reviewed. The value of rotary coring and partially destructive investigation techniques are described in relation to the evaluation of masonry. The principles of digital sonic lime domain testing, digital sonic frequency domain testing and digital time domain radar testing are explained and described in relation to applications to masonry bridges and retaining wall structures. From the case studies it is shown that the techniques of digital sonic impulse hammer testing and digital impulse radar testing are complementary in nature and can be used to cost effectively identify the geometries of masonry bridges in addition to fault detection, location. 53843 Rogers, L.M.; Phillips, L.P. Acoustic emission and ultrasonic testing of concrete structures Structural Integrity Assessment. Edited by P. Stanley. pp. 300-313. Elsevier Applied Science (1992) This paper gives an example of AE testing of concrete and shows how the same equipment can be used to make ultrasonic pulse velocity and signal attenuation measurements on bulk concrete at distances of one to two metres, depending on the composition and quality of the concrete, and how this range of detection can be further extended. The examples given are (i) The inspection of diaphragm walls by the sonic coting method, where transmit and receive transducers are pulled through water-fried tubes built into the steel reinforcement and (ii) Testing the bulk quality and surface condition of bridge support columns using transducers implanted into the structure.
Al Qadi, I.L.; Weyers, R.E.; Galagedera, N.L.; Cady, P.D. Condition evaluation of concrete bridges relative to reinforcement corrosion. Volume 4. Deck membrance effectiveness and a method for evaluating, membrane integrity 53482
Virginia Polytechnic Inst. and State Univ., Blacksburg (United States), PB93-142990/GAR, 152pp. (Sep. 1992) An intensive investigation was conducted to evaluate membrane performance and effectiveness. The main objectives of this study were to: develop a nondestructive test method for evaluating the integrity of membranes in place; investigate the effectiveness of membranes, relative to chloride barrier properties, as a function of membrane integrity; and evaluate the factors that may affect membrane performance, including membrane type and age, climate, and deicer application rate. A nondestructive methodology using ultrasonic pulse velocity was developed to predict the membrane status. The laboratory study and field validation concluded that preformed membrane systems reduce chloride intrusion, when properly installed and overlaid with at least 2.5-in. (6.4-cm) hot-mix asphalt, which should be kept in a good service condition. An average life of 40 years is expected for preformed membrane systems and an increase of 25 years in bridge deck life is expected.
Bassim, M.N. Detection of fatigue crack propagation with acoustic emission 53078
NDT&E International, VoL 25, No. 6, pp. 287-289 (Dec. 1992) In this paper, relationships relating acoustic emission to fatigue crack growth are developed. Acoustic emission equations, similar to Paris' law, are derived which allow determination of the stress intensity factor and the crack growth rate. These principles are embodied in a second-generatinn system which automatically and continuously determines these parameters. The approach is applied in the laboratory as well as to structures including bridges, air frames and transmission towers for electrical power.
Plecnik, J.M.; Henriquez, O.E. Acoustic emissions on complex composite bridge
55659
deck structures Advanced Materials: Expanding the Horizons. 25th International SAMPE Technical Conference, Philadelphia, Pennsylvania (United States), 26-28 Oct. 1993. Vol. 25, pp. 759-770. Edited by R. Trabocco and T. Lynch, SAMPE (1993) This program studies the performance of an innovative modular fiberglass composite bridge deck system. Both the commercial AASHTO HS20-44 truck load and the Alternative Military load were applied to composite deck specimens in a series of fatigue tests. Throughout these tests, performance of the specimens was monitored by using the acoustic emissions (AE). It was found that AE activity during the first fatigue cycles can be used to predict whether or not the deck is appropriate to withstand several million truck load cycles. The study was performed on two 213 cm (7 ft.) wide deck specimens. Test setups simulated two different types of mechanical connections necessary for the modular bridge deck system. Results indicate the composite deck is adequate to withstand the design loads.
Zhwo, Z.; Haldar, A.; Breen, F L. Fatigue-reliability updating through inspections of steel bridges 55473
Journal of Structural Engineering, Vol. 120, No. 5, pp. 1624-1650 (May 1994) The sensitivity and capability of inspection mathods, including ultrasonic inspection, are investigated. The detection events are classified into three cases, no crack detection, crack detection but without size measurement, and crack detection with the crack-size measurement. Using the information from k inspections, the distributions of the basic random variables and the corresponding reliability index are updated. It is concluded that the inspection results can be used to maintain the fatigue-damage integrity of steel bridges.
55314 Hu, K.K.; Gattani, S3V.; Russell, E.R.; Swartz, S.E. An inexpensive pavement condition monitoring system International Conference on Nondestructive Testing of Concrete in the Infrastructure, Dearborn, Michigan (United States), 9-11 Jun. 1993. pp. 451-466. Society for Experimental Mechanics, Inc., (1993) ISBN 10912053429 A concept is explored wherein a portable, person-operated system with modest capabilities and cost is used. This has the ability to map surface irregularities - especially rutting/profiles and surface defects - spalling, cracking, holes in an automated fashion. Data are obtained using an ultrasonic transducer and a video still camera. These are stored digitally to be reconstructed later and merged spatially into a map using appropriate imaging enhancement of pavement distress features of interest. In its present form, the device is best suited for analyzing bridge decks. This will allow the sponsor to assess quickly the condition of a bridge deck and to keep record of changes over time in a convenient form on a video tape and/or disk. 55057 Bligh, R.P.; Nakirekanti, S.; Bray, D.E.; James, R.W. Evaluation of NDE techniques for detecting grout defects in cable stays Materials Evaluation, Vol. 52, No. 4, pp. 508-514 (Apr. 1994) Problems with corrosion of steel strands in grouted bridge cable stays have raised concern about the integrity of the grout layer protecting the strands. Bleed water may accumulate in the grout layer if voids or bubbles are trapped during the grouting process, leading to localized corrosion of the cables. A research study has been undertaken to assess various nondestructive evaluation (NDE) methods for inspection of this grout layer. Methods studied include ultrasonics, X-ray radiography, computed tomography, and neutron radiography. Representative models of grouted cable stays were prepared with manufactured defects to investigate the feasibility of these techniques.
390
Declerck, P. Bibliographic study of georadar principles, applications, advantages, and inconvenience. (In French, English abstract) 54877
Centre de Recherches Routieres, Brussels (Belgium), N9318993/4/GAR, 53pp. (1991) The literature survey reviews some 25 years of reporting on attempts to use electromagnetic pulses for nondestructive material testing. The higher the frequency, the higher the resolution and the smaller the depth of penetration. Special antennas are required for specific applications such as the detection of linear structures (pipes, cables) or the investigation of walls and bridge decks. Radar is a fast, high- yield and continuous method of surveying and the waves are not stopped by voids or cracks, unlike acoustic waves or seismic vibrations. Radar operates well in poorly conducting materials and less well in wet or clayey soils. 54628 Forde, M.C.; McCavitt, N. Sonic NDT and radar testing of masonry British Journal of Non-destructive Testing, Vol. 36, No. 3, pp. 140145,147 (Mar. 1994) The various methods of non-destructively testing masonry are reviewed. The value of rotary coring and partially destructive investigation techniques are described in relation to the evaluation of masonry. The principles of digital sonic lime domain testing, digital sonic frequency domain testing and digital time domain radar testing are explained and described in relation to applications to masonry bridges and retaining wall structures. From the case studies it is shown that the techniques of digital sonic impulse hammer testing and digital impulse radar testing are complementary in nature and can be used to cost effectively identify the geometries of masonry bridges in addition to fault detection, location. 53843 Rogers, L.M.; Phillips, L.P. Acoustic emission and ultrasonic testing of concrete structures Structural Integrity Assessment. Edited by P. Stanley. pp. 300-313. Elsevier Applied Science (1992) This paper gives an example of AE testing of concrete and shows how the same equipment can be used to make ultrasonic pulse velocity and signal attenuation measurements on bulk concrete at distances of one to two metres, depending on the composition and quality of the concrete, and how this range of detection can be further extended. The examples given are (i) The inspection of diaphragm walls by the sonic coting method, where transmit and receive transducers are pulled through water-fried tubes built into the steel reinforcement and (ii) Testing the bulk quality and surface condition of bridge support columns using transducers implanted into the structure.
Al Qadi, I.L.; Weyers, R.E.; Galagedera, N.L.; Cady, P.D. Condition evaluation of concrete bridges relative to reinforcement corrosion. Volume 4. Deck membrance effectiveness and a method for evaluating, membrane integrity 53482
Virginia Polytechnic Inst. and State Univ., Blacksburg (United States), PB93-142990/GAR, 152pp. (Sep. 1992) An intensive investigation was conducted to evaluate membrane performance and effectiveness. The main objectives of this study were to: develop a nondestructive test method for evaluating the integrity of membranes in place; investigate the effectiveness of membranes, relative to chloride barrier properties, as a function of membrane integrity; and evaluate the factors that may affect membrane performance, including membrane type and age, climate, and deicer application rate. A nondestructive methodology using ultrasonic pulse velocity was developed to predict the membrane status. The laboratory study and field validation concluded that preformed membrane systems reduce chloride intrusion, when properly installed and overlaid with at least 2.5-in. (6.4-cm) hot-mix asphalt, which should be kept in a good service condition. An average life of 40 years is expected for preformed membrane systems and an increase of 25 years in bridge deck life is expected.
Bassim, M.N. Detection of fatigue crack propagation with acoustic emission 53078
NDT&E International, VoL 25, No. 6, pp. 287-289 (Dec. 1992) In this paper, relationships relating acoustic emission to fatigue crack growth are developed. Acoustic emission equations, similar to Paris' law, are derived which allow determination of the stress intensity factor and the crack growth rate. These principles are embodied in a second-generatinn system which automatically and continuously determines these parameters. The approach is applied in the laboratory as well as to structures including bridges, air frames and transmission towers for electrical power.