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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 National 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 CRP STAFF FOR NCHRP SYNTHESIS 519 Christopher J. Hedges, Director, Cooperative Research Programs Lori L. Sundstrom, Deputy Director, Cooperative Research Programs Tanya M. Zwahlen, Consulting Project Manager Cheryl Keith, Senior Program Assistant Eileen P. Delaney, Director of Publications Natalie Barnes, Associate Director of Publications Kami Cabral, Editor NCHRP PROJECT 20-05 PANEL Brian A. Blanchard, Florida DOT, Tallahassee, FL (Chair) Stuart D. Anderson, Texas A&M University, College Station, TX Socorro Briseno, California DOT, Sacramento, CA David M. Jared, Georgia DOT, Forest Park, GA Cynthia L. Jones, Ohio DOT, Columbus, OH Malcolm T. Kerley, NXL, Richmond, VA John M. Mason, Jr., Auburn University, Auburn, AL Roger C. Olson, Minnesota DOT, Bloomington, MN (retired) Benjamin T. Orsbon, South Dakota DOT, Pierre, SD Randall R. Park, Utah DOT, Salt Lake City, UT Robert L. Sack, New York State DOT, Albany, NY Francine Shaw Whitson, FHWA, Washington, DC Joyce N. Taylor, Maine DOT, Augusta, ME Jack Jernigan, FHWA Liaison Stephen F. Maher, TRB Liaison TOPIC 48-05 PANEL Thomas Birnbrich, Ohio DOT, Columbus, OH Bryan Bradley, Iowa DOT, Ames, IA Matthew DeLong, Michigan DOT, Lansing, MI JoAnn Kurts, Louisiana DOTD, Baton Rouge, LA Mohammad Najafi, The University of Texas at Arlington, Arlington, TX C. Paul Scott, Cardno, Dumfries, VA Alana M. Spendlove, Utah DOT, Salt Lake City, UT Morgan Kessler, FHWA Liaison C. K. Leuderalbert, FHWA Liaison Stephen F. Maher, TRB Liaison
FOREWORD Highway administrators, engineers, and researchers often face problems for which information already exists, either in documented form or as undocumented experience and practice. This infor- mation may be fragmented, scattered, and unevaluated. As a consequence, full knowledge of what has been learned about a problem may not be brought to bear on its solution. Costly research findings may go unused, valuable experience may be overlooked, and due consideration may not be given to recommended practices for solving or alleviating the problem. There is information on nearly every subject of concern to highway administrators and engineers. Much of it derives from research or from the work of practitioners faced with problems in their day- to-day work. To provide a systematic means for assembling and evalu ating such useful information and to make it available to the entire highway community, the American Association of State High- way and Transportation Officialsâthrough the mechanism of the National Cooperative Highway Research Programâauthorized the Transportation Research Board to undertake a continuing study. This study, NCHRP Project 20-05, âSynthesis of Information Related to Highway Problems,â searches out and synthesizes useful knowledge from all available sources and prepares concise, documented reports on specific topics. Reports from this endeavor constitute an NCHRP report series, Synthesis of Highway Practice. This synthesis series reports on current knowledge and practice, in a compact format, without the detailed directions usually found in handbooks or design manuals. Each report in the series provides a compendium of the best knowledge available on those measures found to be the most successful in resolving specific problems. PREFACE By Tanya M. Zwahlen Staff Officer Transportation Research Board The objectives of this synthesis project were to summarize trenchless technologies used for the renewal of stormwater systems, including new, emerging, and underutilized methods, and to identify future research needs. This information can help highway stakeholders identify effective technologies used in the structural and functional renewal of stormwater facilities and can inform facility owners in their efforts to minimize negative impacts and maximize cost benefits. The information contained in this synthesis was obtained using three sources. First, a literature review was conducted on all existing research concerning the use of trenchless technologies, includ- ing international experience. Second, a survey was distributed to state departments of trans- portation, municipalities, and special districts to identify successful examples of the use of these technologies. The survey and list of responding agencies are included as Appendix A and Appendix B, respectively. These appendices can be found on the TRB website (www.trb.org) by searching for âNCHRP Synthesis 519.â Finally, case examples were developed involving the use of different technologies and conditions where they are applicable. David C. Ward of Shannon & Wilson, Inc., collected and synthesized the information and wrote the report. The members of the topic panel are acknowledged on page iv. This synthesis is an immediately useful document that records the practices that were acceptable within the limitations of the knowledge available at the time of its preparation.
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. 1 Summary 3 Chapter 1 Introduction 3 What Is Trenchless Renewal of Stormwater Systems? 3 Background 4 Study Methodology 6 Organization of Synthesis 6 Chapter Summary 7 Chapter 2 Trenchless Renewal Methods 7 Introduction 7 Definitions 17 Summary of Advantages and Challenges 17 Emerging Technologies 21 Chapter Summary 22 Chapter 3 Current Practice and Experience 22 Introduction 22 Experience 22 Methods and Frequency Used 24 Satisfaction with Methods Used 26 Increasing Trenchless Renewal Use 27 Method Selection 29 Reasons for Using Trenchless Renewal 30 Defects Commonly Mitigated and Satisfaction 31 Costs 32 Underutilized Methods 32 Chapter Summary 34 Chapter 4 Conclusions 37 References 39 Bibliography 42 Glossary 44 Acronyms and Abbreviations 45 Appendix A Survey Questionnaire 46 Appendix B Agencies Responding to Questionnaire C O N T E N T S
1 Aging stormwater facilities can be replaced using open-cut or trenchless replacement, or the service life of the existing stormwater facilities can be extended using trenchless renewal. This synthesis focuses primarily on the trenchless renewal of culverts typically ranging in diameter from 12 in. to over 12 ft with both circular and noncircular cross-sections. While most aging culverts consist of either corrugated metal or concrete pipe, some of the renewal methods discussed in this synthesis are also applicable to other pipe types. Both trenchless replacement and trenchless renewal methods can reduce negative impacts associated with surface disruption by moving the work area outside of the travel lanes and concentrating the construction impacts off the roadway. Trenchless renewal can extend the service life of existing stormwater facilities by addressing decay such as corrosion, abrasion, and erosion; reducing or eliminating infiltration and exfiltration; and providing a structural repair or improving the structural capacity of culverts, pipelines, manholes, and related stormwater structures. In some situations, trenchless renewal can even improve the hydraulic capacity of the stormwater system. The purpose of NCHRP Synthesis 519 is to summarize trenchless technologies used for the renewal of stormwater systems. The six trenchless renewal methods described in this synthesis include (1) cured-in-place pipe (CIPP), (2) sliplining (SL), (3) modified sliplining (MSL), (4) in-line replacement (ILR), (5) spray-in-place pipe (SIPP), and (6) close-fit pipe (CFP). The use of manhole renewal and invert paving are also briefly discussed. The information in this synthesis was gathered through a literature review, a screening survey of state departments of transportation (DOTs), and interviews. The information gathered was focused on the methods used, decision criteria used to select a renewal method, limiting factors on the applicability of specific trenchless renewal methods, successful practices, emergent or underutilized methods, and methods from other industries. The survey was sent to the 50 state DOTs and 43 responses were received from 40 state DOTs. Survey results indicate that while 88% of the DOT respondents have experience with trenchless renewal, the majority (60%) only have experience with one or two methods. Only 8% of the DOT respondents have experience with all six primary methods. Survey results indicate that SL and CIPP are the two most commonly used methods for stormwater system renewal. The need to maintain the existing hydraulic capacity of the stormwater system was identified both by experienced and non-experienced DOTs as a primary reason for not using trenchless renewal. Based solely on this criterion, SIPP, MSL, ILR, and CFP appear to be underutilized. These four methods do not generally result in a significant reduction in hydraulic capacity, and ILR can be used to increase the pipe size and in some cases SIPP liners, MSL, and CFP can improve the hydraulic capacity of some pipes. S u m m a r y The Renewal of Stormwater Systems Using Trenchless Technologies
2 The renewal of Stormwater Systems using Trenchless Technologies Questionnaire results indicate that the primary means of selecting the trenchless renewal method is experience-based, followed closely by in-house expert/in-house consultation. This may be part of the reason that most DOTs only have experience with one or two meth- ods and that SL and CIPP pipe are the two most commonly used methods. Over 90% of the DOTs that use one or two methods use SL, and about 60% of DOTs that use two methods use both SL and CIPP. The DOTs are satisfied with the commonly used SL and CIPP. They are also generally satisfied or very satisfied with the ability of trenchless renewal to address defects, such as corrosion; leaks or infiltration; loose or open joints; and cracks, breaks, or splits. Common causes of cost overruns and claims were identified as changed or differing conditions associated with the existing pipe or subsurface conditions. Of the respondents, 64% indicated that cost overruns were generally less than 10%. DOTs can benefit from future research and synthesis of structural testing and analysis of SIPP and CIPP liners, additional published information on less commonly used ILR methods, detailed cost data, and standardized trenchless replacement and renewal selection guidelines. Some future research on these topics has already been planned. For example, a study entitled âStructural Design Methodology for Spray Applied Pipe Liners in Gravity Storm Water Conveyance Conduitsâ has been funded by the Transportation Pooled Fund Program.