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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 REPORT 734 Hydraulic Loss Coefficients for Culverts Blake P. Tullis Utah State UniverSity Logan, UT Subscriber Categories Hydraulics and Hydrology TRANSPORTAT ION RESEARCH BOARD WASHINGTON, D.C. 2012 www.TRB.org 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 provides the most effective approach to the solution of 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 develops increasingly complex problems of wide interest to highway authorities. These problems are best studied through a coordinated program of cooperative research. In recognition of these needs, the highway administrators of the American Association of State Highway and Transportation Officials initiated in 1962 an objective national highway research program employing modern scientific techniques. This program is supported on a continuing basis by funds from participating member states of the Association and it receives the full cooperation and support of the Federal Highway Administration, United States Department of Transportation. The Transportation Research Board of the National Academies was requested by the Association to administer the research program because of the Boardâs recognized objectivity and understanding of modern research practices. The Board is uniquely suited for this purpose as it maintains an extensive committee structure from which authorities on any highway transportation subject may be drawn; it possesses avenues of communications and cooperation with federal, state and local governmental agencies, universities, and industry; its relationship to the National Research Council is an insurance of objectivity; it maintains a full-time research correlation staff of specialists in highway transportation matters to bring the findings of research directly to those who are in a position to use them. The program is developed on the basis of research needs identified by chief administrators of the highway and transportation departments and by committees of AASHTO. Each year, specific areas of research needs to be included in the program are proposed to the National Research Council and the Board by the American Association of State Highway and Transportation Officials. Research projects to fulfill these needs are defined by the Board, and qualified research agencies are selected from those that have submitted proposals. Administration and surveillance of research contracts are the responsibilities of the National Research Council and the Transportation Research Board. The needs for highway research are many, and the National Cooperative Highway Research Program can make significant contributions to the solution of 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 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 at: http://www.national-academies.org/trb/bookstore Printed in the United States of America NCHRP REPORT 734 Project 15-24 ISSN 0077-5614 ISBN 978-0-309-25867-8 Library of Congress Control Number 2012952178 Â© 2012 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, FTA, or Transit Development Corporation 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 project that is the subject of this report was a part of the National Cooperative Highway Research Program, conducted by the Transportation Research Board with the approval of the Governing Board of the National Research Council. The members of the technical panel selected to monitor this project and to review this report were chosen for their special competencies and with regard for appropriate balance. The 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 Governing Board of the National Research Council. 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 Research Council, or the program sponsors. The Transportation Research Board of the National Academies, the National Research Council, 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 is a private, nonprofit, self-perpetuating society of distinguished scholars engaged in scientific and engineering research, dedicated to the furtherance of science and technology and to their use for the general welfare. On the authority of the charter granted to it by the Congress in 1863, the Academy has a mandate that requires it to advise the federal government on scientific and technical matters. Dr. Ralph J. Cicerone is president of the National Academy of Sciences. The National Academy of Engineering was established in 1964, under the charter of the National Academy of Sciences, as a parallel organization of outstanding engineers. It is autonomous in its administration and in the selection of its members, sharing with the National Academy of Sciences the responsibility for advising the federal government. The National Academy of Engineering also sponsors engineering programs aimed at meeting national needs, encourages education and research, and recognizes the superior achievements of engineers. Dr. Charles M. Vest is president of the National Academy of Engineering. The Institute of Medicine was established in 1970 by the National Academy of Sciences to secure the services of eminent members of appropriate professions in the examination of policy matters pertaining to the health of the public. The Institute acts under the responsibility given to the National Academy of Sciences by its congressional charter to be an adviser to the federal government and, on its own initiative, to identify issues of medical care, research, and education. Dr. Harvey V. Fineberg is president of the Institute of Medicine. The National Research Council was organized by the National Academy of Sciences in 1916 to associate the broad community of science and technology with the Academyâs purposes of furthering knowledge and advising the federal government. Functioning in accordance with general policies determined by the Academy, the Council has become the principal operating agency of both the National Academy of Sciences and the National Academy of Engineering in providing services to the government, the public, and the scientific and engineering communities. The Council is administered jointly by both Academies and the Institute of Medicine. Dr. Ralph J. Cicerone and Dr. Charles M. Vest are chair and vice chair, respectively, of the National Research Council. The Transportation Research Board is one of six major divisions of the National Research Council. The mission of the Transporta- tion Research Board is to provide leadership in transportation innovation and progress through research and information exchange, conducted within a setting that is objective, interdisciplinary, and multimodal. The Boardâs varied activities 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 individu- als interested in the development of transportation. www.TRB.org www.national-academies.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 research project herein was performed under NCHRP Project 15-24 by the Utah Water Research Laboratory, Department of Civil and Environmental Engineering, at Utah State University (USU). USU was the contractor and fiscal administrator for this study. Dr. Blake P. Tullis, Associate Professor of Civil and Environmental Engineering at USU, was the Proj- ect Director and Principal Investigator. Other research participants and authors include Tyler G. Allen, Ph.D. candidate at USU; Gary M. Haderlie, MS student at USU; Derek S. Anderson, MS student at USU; S. Collin Robinson, MS student at USU; Dale Lentz, MS student at USU; and Steven L. Barfuss, Assistant Research Professor at USU. The work was done under the general supervision of Dr. Blake P. Tullis. CRP STAFF FOR NCHRP REPORT 734 Christopher W. Jenks, Director, Cooperative Research Programs Crawford F. Jencks, Deputy Director, Cooperative Research Programs David A. Reynaud, Senior Program Officer Megan A. Chamberlain, Senior Program Assistant Eileen P. Delaney, Director of Publications Ellen M. Chafee, Editor NCHRP PROJECT 15-24 PANEL Field of DesignâArea of General Design Merril E. Dougherty, Indiana DOT, Indianapolis, IN (Chair) Steven R. Abt, Colorado State University, Fort Collins, CO M. Saeed Choudhary, Ontario Ministry of Transportation, St. Catharines, ON Christopher Hack, Atkins, Tallahassee, FL J. Sterling Jones, Goochland, VA Shawn McLemore, Jacobs Engineering Group, Inc., Tallahassee, FL Richard A. Phillips, Sioux Falls, SD Philip L. Thompson, Alexandria, VA Kornel Kerenyi, FHWA Liaison Stephen F. Maher, TRB Liaison
F O R E W O R D Traditional culvert applications were designed by determining the minimum culvert size that will pass the specified design flood. In recent years, culvert performance objectives and designs have been expanded to include other considerations such as improving fish and/or terrestrial animal passage and rehabilitating old, deteriorated culverts. This project evaluated culvert geometries associated with these new applications to develop the hydraulic relation- ships, including loss coefficients. The report will be of interest to hydraulic engineers and environmental staff. Culverts are designed and constructed to be hydraulically efficient, such that they are able to pass flood flows without overtopping the road embankment. Flow passing through a culvert typically experiences an increase in velocity, relative to the approach channel flow, due to reductions in cross-sectional flow area. Increased flow velocity can cause additional outlet erosion as well as be a problem for many types of migratory species. In addition to migratory species, resident fish such as juvenile salmon can also be affected by culverts. Juvenile salmon move up and down streams as population pressures and food sources change. If high velocities in culverts provide barriers to this movement, food sources and population may be limited. Other fish species may have requirements similar to those of juvenile salmon or may require upstream movement for spawning. Research in the area of culvert hydraulics has centered on concrete box culverts and circular corrugated metal pipe culverts. The hydraulic analyses of these culvert types have been well defined for conventional installations, but not for environmentally sensitive and nontraditional culverts. It is desirable to design and construct some culvert crossings to minimize their impact on the natural environment. Culverts are now being designed to maintain natural velocities and minimize turbulence to allow migratory species to pass through the culvert barrel. Such designs may add baffles on the invert, bury the culvert invert, or use bottomless culverts to provide for a natural stream invert. Other designs use larger and wider culverts to reduce the amount of contraction and acceleration. In order to design these culverts that minimize impacts to the natural stream environment, designers need the associated hydraulic equations and loss coefficients to be evaluated and made more accurate. In NCHRP Project 15-24, Utah State University conducted physical, numerical, and computer modeling to refine existing hydraulic relationships and develop new ones for analysis and design of culverts for conventional and nontraditional, environ- mentally sensitive installations. By David A. Reynaud Staff Officer Transportation Research Board
C O N T E N T S 1 Chapter 1 Introduction 1 1.1 Project Introduction 2 1.2 Culvert Hydraulics 4 1.3 Report Layout Summary 5 Chapter 2 Buried-Invert or Embedded Culverts 5 2.1 Summary 5 2.2 Introduction 6 2.3 Research Objectives 7 2.4 Experimental Method 11 2.5 Experimental Results 15 2.6 Conclusions 18 Chapter 3 Slip-Lined Culverts 18 3.1 Summary 18 3.2 Introduction 19 3.3 Research Objectives 20 3.4 Experimental MethodâOutlet Control Testing 21 3.5 Experimental Results 22 3.6 Conclusions 25 Chapter 4 Culvert Exit Loss 25 4.1 Summary 25 4.2 Introduction 26 4.3 Borda-Carnot Derivation 27 4.4 Experimental Results 30 4.5 Example of Application 30 4.6 Conclusions 31 Chapter 5 Inlet Control Hydraulics of Multiple Circular Culverts 31 5.1 Summary 31 5.2 Introduction 32 5.3 Research Objectives 33 5.4 Experimental Method 36 5.5 Experimental Results 49 5.6 Conclusions 50 Chapter 6 The Behavior of Hydraulic Roughness Coefficients in Open Channel Flow 50 6.1 Summary 50 6.2 Introduction 51 6.3 Background 52 6.4 Experimental Method 55 6.5 Discussion and Analysis 58 6.6 Conclusions
60 Chapter 7 Open Channel Flow Resistance: the Hydraulic Radius Dependence of Manningâs Equation and Manningâs n 60 7.1 Summary 60 7.2 Introduction 61 7.3 Background 62 7.4 Experimental Method 63 7.5 Discussion and Results 67 7.6 Conclusions 68 Chapter 8 Open Channel Flow Resistance: Composite Roughness 68 8.1 Summary 69 8.2 Introduction 70 8.3 Background 72 8.4 Experimental Setup 73 8.5 Experimental Results 78 8.6 Conclusions 79 References 81 Notation 84 Appendix A Buried-Invert Culvert Outlet Control Experimental Data Set (Tabular Support Data for Chapter 2) 93 Appendix B Buried-Invert Culvert Inlet Control Experimental Data Set (Tabular Support Data for Chapter 2) 103 Appendix C Outlet Control Experimental Data Set for Traditional Projecting and Slip-Lined Inlet End Treatments (Tabular Support Data for Chapter 3) 105 Appendix D Inlet Control Experimental Data Set for Traditional Projecting and Slip-Lined Inlet End Treatments (Tabular Support Data for Chapter 3) 108 Appendix E Single and Multibarrel Culvert Experimental Data Sets (Tabular Support Data for Chapter 5) Note: Many of the photographs, figures, and tables in this report 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.