{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/95317"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/95317","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"Evaluation of internal damage in reinforced concrete elements using ultrasonic tomography","abstract":"DSpace SAF Submission Ingestion Package generated from Vireo submission #10243 on 2017-02-28 at 14:47:38","abstract_html":"DSpace SAF Submission Ingestion Package generated from Vireo submission #10243 on 2017-02-28 at 14:47:38","abstract_has_math":false,"creators":["Choi, Hajin"],"institution":"University of Illinois at Urbana-Champaign","degree_name":"Ph.D.","degree_level":"Dissertation","degree_discipline":"Civil Engineering","degree_department":null,"school":null,"contributors":["Popovics, John S.","Do, Minh N.","Golparvar-Fard, Mani","Chao, Shih-Ho"],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2017,"date_issued":"2017-03-01T15:48:42Z","date_published":"2017-03-01T15:48:42Z","updated_at":"2026-07-22T22:26:37Z","subjects":["Damage assessment","Ultrasonic","Non-destructive evaluation","Tomography","Concrete"],"languages":["en"],"rights":["Copyright 2016 Hajin Choi"],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"http://hdl.handle.net/2142/95317","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Popovics, John S.","Do, Minh N.","Golparvar-Fard, Mani","Chao, Shih-Ho"]},{"key":"dc:creator","label":"Author","values":["Choi, Hajin"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2017-03-01T15:48:42Z","2016-11-16","2016-12"]},{"key":"dc:type","label":"Dc Type","values":["text"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Civil Engineering"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Dissertation"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Ph.D."]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["University of Illinois at Urbana-Champaign"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Damage assessment","Ultrasonic","Non-destructive evaluation","Tomography","Concrete"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["en"]},{"key":"dc:rights","label":"Dc Rights","values":["Copyright 2016 Hajin Choi"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["http://hdl.handle.net/2142/95317"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["DSpace SAF Submission Ingestion Package generated from Vireo submission #10243 on 2017-02-28 at 14:47:38","Quality control and quality assurance (QC/QA) of the concrete infrastructure has become an important national issue, especially because construction inaccuracies and invisible internal defects can result in unexpected structural response and failure. In order to evaluate the condition of an existing concrete structure, non-destructive testing (NDT) has been widely used as an assessment tool. Ultrasonic pulse velocity (UPV) is an efficient method to characterize the condition of concrete elements, and tomographic imaging is a powerful tool for visually identifying internal damage. However, the implementation of UPV data within a tomographic imaging scheme for application to full-scale concrete (RC) structures has not been realized to date because of practical and technological restrictions. In this dissertation, some of those barriers are overcome by using contactless air-coupled ultrasonic sensors in a scanning test configuration to acquire large amounts of ultrasonic data to create ultrasonic tomograms of large-scale concrete structures. The development of the testing system is described. The measurements are carried out using an automated robotic scanning frame using new sensing technology. Image reconstruction algorithms, including synthetic aperture focusing technique (SAFT) and algebraic reconstruction technique (ART), are reviewed and evaluated for application to imaging of full-scale RC columns. The performance of the data collection system and selected optimal imaging approach are verified through tests on a RC column test sample containing embedded artificial defects. The obtained tomographic images are compared with those from a commercially available ultrasonic imaging device. A comprehensive visualization scheme to characterize the column test sample, based on fusion of integrated ultrasonic tomography and 3-D computer vision, is presented. Such integrated visualization provides holistic characterization of the test sample. Next, the utility of attenuation tomography for enhanced damage detection is evaluated, both through numerical simulation and experimental studies. Finally, the developed ultrasonic tomographic testing system is applied to full-scale RC columns and slab-beam-column sub-assemblages subjected to simulated earthquake loads. Different concrete types, including normal reinforced concrete and high performance fiber-reinforced concrete, and seismic different loading schemes are considered. Comparisons of ultrasonic tomograms and strain gauge data illustrate the potential for velocity and attenuation tomography to monitor internal damage progression of structural RC elements both at global and local levels.","Submission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2017-02-28 without embargo terms","The student, Hajin Choi, accepted the attached license on 2016-11-14 at 23:43.","The student, Hajin Choi, submitted this Dissertation for approval on 2016-11-14 at 23:50.","This Dissertation was approved for publication on 2016-11-16 at 11:54.","Made available in DSpace on 2017-03-01T15:48:42Z (GMT). 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In order to evaluate the condition of an existing concrete structure, non-destructive testing (NDT) has been widely used as an assessment tool. Ultrasonic pulse velocity (UPV) is an efficient method to characterize the condition of concrete elements, and tomographic imaging is a powerful tool for visually identifying internal damage. However, the implementation of UPV data within a tomographic imaging scheme for application to full-scale concrete (RC) structures has not been realized to date because of practical and technological restrictions. In this dissertation, some of those barriers are overcome by using contactless air-coupled ultrasonic sensors in a scanning test configuration to acquire large amounts of ultrasonic data to create ultrasonic tomograms of large-scale concrete structures. The development of the testing system is described. The measurements are carried out using an automated robotic scanning frame using new sensing technology. Image reconstruction algorithms, including synthetic aperture focusing technique (SAFT) and algebraic reconstruction technique (ART), are reviewed and evaluated for application to imaging of full-scale RC columns. The performance of the data collection system and selected optimal imaging approach are verified through tests on a RC column test sample containing embedded artificial defects. The obtained tomographic images are compared with those from a commercially available ultrasonic imaging device. A comprehensive visualization scheme to characterize the column test sample, based on fusion of integrated ultrasonic tomography and 3-D computer vision, is presented. Such integrated visualization provides holistic characterization of the test sample. Next, the utility of attenuation tomography for enhanced damage detection is evaluated, both through numerical simulation and experimental studies. Finally, the developed ultrasonic tomographic testing system is applied to full-scale RC columns and slab-beam-column sub-assemblages subjected to simulated earthquake loads. Different concrete types, including normal reinforced concrete and high performance fiber-reinforced concrete, and seismic different loading schemes are considered. Comparisons of ultrasonic tomograms and strain gauge data illustrate the potential for velocity and attenuation tomography to monitor internal damage progression of structural RC elements both at global and local levels.","Submission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2017-02-28 without embargo terms","The student, Hajin Choi, accepted the attached license on 2016-11-14 at 23:43.","The student, Hajin Choi, submitted this Dissertation for approval on 2016-11-14 at 23:50.","This Dissertation was approved for publication on 2016-11-16 at 11:54.","Made available in DSpace on 2017-03-01T15:48:42Z (GMT). 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