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2017 N A T I O N A L C O O P E R A T I V E H I G H W A Y R E S E A R C H P R O G R A M NCHRP RESEARCH REPORT 848 Inspection Guidelines for Bridge Post-Tensioning and Stay Cable Systems Using NDE Methods Stefan Hurlebaus Mary Beth D. Hueste Madhu M. Karthik Tevfik Terzioglu Texas a&M TransporTaTion insTiTuTe The Texas a&M universiTy sysTeM College Station, TX Subscriber Categories Bridges and Other Structures Research sponsored by the American Association of State Highway and Transportation Officials in cooperation with the Federal Highway Administration
NATIONAL COOPERATIVE HIGHWAY RESEARCH PROGRAM Systematic, well-designed research is the most effective way to solve many problems facing highway administrators and engineers. Often, highway problems are of local interest and can best be studied by highway departments individually or in cooperation with their state universities and others. However, the accelerating growth of highway transportation results in increasingly complex problems of wide inter- est to highway authorities. These problems are best studied through a coordinated program of cooperative research. Recognizing this need, the leadership of the American Association of State Highway and Transportation Officials (AASHTO) in 1962 ini- tiated an objective national highway research program using modern scientific techniquesâthe National Cooperative Highway Research Program (NCHRP). NCHRP is supported on a continuing basis by funds from participating member states of AASHTO and receives the full cooperation and support of the Federal Highway Administration, United States Department of Transportation. The Transportation Research Board (TRB) of the National Academies of Sciences, Engineering, and Medicine was requested by AASHTO to administer the research program because of TRBâs recognized objectivity and understanding of modern research practices. TRB is uniquely suited for this purpose for many reasons: TRB maintains an extensive com- mittee structure from which authorities on any highway transportation subject may be drawn; TRB possesses avenues of communications and cooperation with federal, state, and local governmental agencies, univer- sities, and industry; TRBâs relationship to the Academies is an insurance of objectivity; and TRB maintains a full-time staff of specialists in high- way transportation matters to bring the findings of research directly to those in a position to use them. The program is developed on the basis of research needs identified by chief administrators and other staff of the highway and transporta- tion departments and by committees of AASHTO. Topics of the highest merit are selected by the AASHTO Standing Committee on Research (SCOR), and each year SCORâs recommendations are proposed to the AASHTO Board of Directors and the Academies. Research projects to address these topics are defined by NCHRP, and qualified research agencies are selected from submitted proposals. Administration and surveillance of research contracts are the responsibilities of the Acad- emies and TRB. The needs for highway research are many, and NCHRP can make significant contributions to solving highway transportation problems of mutual concern to many responsible groups. The program, however, is intended to complement, rather than to substitute for or duplicate, other highway research programs. Published research reports of the NATIONAL COOPERATIVE HIGHWAY RESEARCH PROGRAM are available from Transportation Research Board Business Office 500 Fifth Street, NW Washington, DC 20001 and can be ordered through the Internet by going to http://www.national-academies.org and then searching for TRB Printed in the United States of America NCHRP RESEARCH REPORT 848 Project 14-28 ISSN 2572-3766 (Print) ISSN 2572-3774 (Online) ISBN 978-0-309-44632-7 Library of Congress Control Number 2017937110 Â© 2017 National Academy of Sciences. All rights reserved. COPYRIGHT INFORMATION Authors herein are responsible for the authenticity of their materials and for obtaining written permissions from publishers or persons who own the copyright to any previously published or copyrighted material used herein. Cooperative Research Programs (CRP) grants permission to reproduce material in this publication for classroom and not-for-profit purposes. Permission is given with the understanding that none of the material will be used to imply TRB, AASHTO, FAA, FHWA, FMCSA, FRA, FTA, Office of the Assistant Secretary for Research and Technology, PHMSA, or TDC endorsement of a particular product, method, or practice. It is expected that those reproducing the material in this document for educational and not-for-profit uses will give appropriate acknowledgment of the source of any reprinted or reproduced material. For other uses of the material, request permission from CRP. NOTICE The research report was reviewed by the technical panel and accepted for publication according to procedures established and overseen by the Transportation Research Board and approved by the National Academies of Sciences, Engineering, and Medicine. The opinions and conclusions expressed or implied in this report are those of the researchers who performed the research and are not necessarily those of the Transportation Research Board; the National Academies of Sciences, Engineering, and Medicine; or the program sponsors. The Transportation Research Board; the National Academies of Sciences, Engineering, and Medicine; and the sponsors of the National Cooperative Highway Research Program do not endorse products or manufacturers. Trade or manufacturersâ names appear herein solely because they are considered essential to the object of the report.
The National Academy of Sciences was established in 1863 by an Act of Congress, signed by President Lincoln, as a private, non- governmental institution to advise the nation on issues related to science and technology. Members are elected by their peers for outstanding contributions to research. Dr. Marcia McNutt is president. The National Academy of Engineering was established in 1964 under the charter of the National Academy of Sciences to bring the practices of engineering to advising the nation. Members are elected by their peers for extraordinary contributions to engineering. Dr. C. D. Mote, Jr., is president. The National Academy of Medicine (formerly the Institute of Medicine) was established in 1970 under the charter of the National Academy of Sciences to advise the nation on medical and health issues. Members are elected by their peers for distinguished contributions to medicine and health. Dr. Victor J. Dzau is president. The three Academies work together as the National Academies of Sciences, Engineering, and Medicine to provide independent, objective analysis and advice to the nation and conduct other activities to solve complex problems and inform public policy decisions. The Academies also encourage education and research, recognize outstanding contributions to knowledge, and increase public understanding in matters of science, engineering, and medicine. Learn more about the National Academies of Sciences, Engineering, and Medicine at www.national-academies.org. The Transportation Research Board is one of seven major programs of the National Academies of Sciences, Engineering, and Medicine. The mission of the Transportation Research Board is to increase the benefits that transportation contributes to society by providing leadership in transportation innovation and progress through research and information exchange, conducted within a setting that is objective, interdisciplinary, and multimodal. The Boardâs varied committees, task forces, and panels annually engage about 7,000 engineers, scientists, and other transportation researchers and practitioners from the public and private sectors and academia, all of whom contribute their expertise in the public interest. The program is supported by state transportation departments, federal agencies including the component administrations of the U.S. Department of Transportation, and other organizations and individuals interested in the development of transportation. Learn more about the Transportation Research Board at www.TRB.org.
C O O P E R A T I V E R E S E A R C H P R O G R A M S AUTHOR ACKNOWLEDGMENTS The authors would like to thank industry partners including Tokyo Ropes, NDT Technologies, Olson Engineering, Infrastructure Preservation Corporation, Digital Wave Corporation, and Dr. Mark Orazem from University of Florida for performing nondestructive evaluation of the mock-up specimens, which was instrumental for the successful completion of the project. The authors would also like to thank Mr. William R. âRandyâ Cox (ASBI), Mr. John Turner and Dr. Mike Mota (CRSI), Mr. Pete Diggs and Mr. Bryan McMurray (Gerdau Long Steel North America), Dr. Zuming Xia and Mr. John Crigler (VSL), Mr. Ray Bauer (Commercial Metals Company), Mr. Mark Huff (BASF), and Mr. Steve Koch (Sumiden Wire Products) for their in-kind contribution of material for the construction of the mock-up specimens. The project team would also like to acknowledge the support of Natasha Boger, Justin Buskmiller, Vir- ginia Foster, Casey Jones, Amir Khalili, HungJoo Kwon, Chris Larsen, Mark McClelland, Katlyn McCoy, Sun He Park, Chi Phung, Ryan Posluszny, John Teets, Joshua White, and Dr. Kyle Wieghaus during the various phases of this project. The assistance from Mr. Duane Wagner and Mr. Gary Gerke from Texas A&M Transportation Institute is also acknowledged. CRP STAFF FOR NCHRP RESEARCH REPORT 848 Christopher J. Hedges, Director, Cooperative Research Programs Lori L. Sundstrom, Deputy Director, Cooperative Research Programs Waseem Dekelbab, Senior Program Officer Gary Jenkins, Senior Program Assistant Eileen P. Delaney, Director of Publications Margaret B. Hagood, Editor NCHRP PROjECT 14-28 PANEL Field of MaintenanceâArea of Maintenance of Way and Structures Jugesh Kapur, Burns and McDonnell, Bismarck, ND (Chair) Alexander K. Bardow, Massachusetts DOT, Boston, MA Rebecca Curtis, Michigan DOT, Lansing, MI Dat Duthinh, National Institute of Standards and Technology, Gaithersburg, MD Ivan R. Lasa, Florida DOT, Gainesville, FL Jeffrey L. âJeffâ Milton, Virginia DOT, Lynchburg, VA Robert A. âRobâ Reis, Department of Water Resources, Sacramento, CA Teddy S. Theryo, Florida DOT, Tallahassee, FL Robert âRobâ Zobel, FHWA Liaison William R. âRandyâ Cox, Industry Liaison James W. Bryant, Jr., TRB Liaison
F O R E W O R D These inspection guidelines describe nondestructive evaluation (NDE) methods for differ- ent condition assessment including corrosion, section loss, breakage, grout conditions, voids, water infiltration, and tendon deterioration in the anchorage systems. The NDE methods are ground penetrating radar (GPR), infrared thermography (IRT), electrical capacitance tomog- raphy (ECT), magnetic flux leakage (MFL), magnetic main flux method (MMFM), impact echo (IE), ultrasonic tomography (UST), ultrasonic echo (USE), sonic/ultrasonic pulse veloc- ity (S/UPV), low frequency ultrasound (LFUT), sounding, visual testing (VT), and electro- chemical impedance spectroscopy (EIS). The material in this report will be of immediate interest to bridge owners and inspectors. Visual bridge inspection of post-tensioning and stay cable systems is difficult because tendons are typically embedded in massive concrete (internal tendons) or opaque ducts (external tendons or stay cables). The current state of NDE technology has limitations for evaluating the condition of bridge post-tensioning and stay cable systems for corrosion, section loss, breakage, grout conditions, voids, water infiltration, and tendon deterioration in the anchorage systems. In recent years, technologies and innovative applications used in other industries may have potential for bridge condition assessments, and NDE technologies applied in combination may also provide opportunities not yet realized. Corrosion, section loss, and breakage have impacts in the form of reduced safety and load capacity, costly rehabilitation actions, and traffic disruption. Condition assessment of post-tensioning and stay cable systems could allow bridge owners to take timely, proactive actions to mitigate or prevent further deterioration and unanticipated failure. The population of structures containing post-tensioning and stay cable systems continues to grow and age. Therefore, the condition assessment of these systems is critical for maintaining public safety. Research was performed under NCHRP Project 14-28 by the Texas A&M Transpor- tation Institute to develop inspection guidelines to assist bridge owners in selecting the most appropriate NDE method for assessing the condition of in-service post-tensioning and stay cable systems. The research agencyâs final report that documents the entire research effort is available on the TRB project website. By Waseem Dekelbab Staff Officer Transportation Research Board
C O N T E N T S 1 Summary 2 Chapter 1 Introduction 2 Purpose 2 Scope 3 Applicability 3 Definitions and Terminology 4 How to Use the Inspection Guidelines 5 Chapter 2 Post-Tensioning and Stay Cable Systems 5 Introduction 5 Overview of Bridge Post-Tensioning Systems 7 Components of Post-Tensioning System 8 Overview of Bridge Stay Cable Systems 9 Components of Stay Cable System 11 Closing Remarks 12 Chapter 3 Deterioration Conditions 12 Introduction 12 Corrosion 14 Section Loss 14 Breakage 15 Compromised Grout 16 Voids 16 Water Infiltration 17 Tendon Deterioration in the Anchorage System 18 Closing Remarks 19 Chapter 4 Capabilities and Limitations of NDE Methods 19 Introduction 19 Electromagnetic Methods 20 Magnetic Methods 21 Mechanical Wave and Vibration Methods 24 Visual Inspection 25 Electrochemical Methods 25 Combinations of Methods 26 Closing Remarks 27 Chapter 5 Condition Assessment of Post-Tensioning and Stay Cable Systems 27 Introduction 27 Types of Inspection 27 Qualifications, Responsibilities, and Training Requirements of Inspectors 28 Planning, Scheduling, and Equipment
28 Evaluation Metrics for Post-Tensioning and Stay Cable Systems 34 Testing Procedures 35 Data Processing 37 Preparing the Report 37 Closing Remarks 38 References A-1 Appendix A Condition Assessment Flowcharts B-1 Appendix B NDE Method Flowcharts for Identifying Defects C-1 Appendix C Testing Procedures D-1 Appendix D Customizing the Decision Matrix E-1 Appendix E Illustrative Examples for Using the Inspection Guidelines Note: Photographs, figures, and tables in this report may have been converted from color to grayscale for printing. The electronic version of the report (posted on the web at www.trb.org) retains the color versions.