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Minimizing Roadway Embankment Damage from Flooding NATIONAL COOPERATIVE HIGHWAY RESEARCH PROGRAM NCHRP SYNTHESIS 496 A Synthesis of Highway Practice
TRANSPORTATION RESEARCH BOARD 2016 EXECUTIVE COMMITTEE* OFFICERS Chair: James M. Crites, Executive Vice President of Operations, DallasâFort Worth International Airport, TX Vice Chair: Paul Trombino III, Director, Iowa Department of Transportation, Ames Executive Director: Neil J. Pedersen, Transportation Research Board MEMBERS VICTORIA A. ARROYO, Executive Director, Georgetown Climate Center; Assistant Dean, Centers and Institutes; and Professor and Director, Environmental Law Program, Georgetown University Law Center, Washington, DC SCOTT E. BENNETT, Director, Arkansas State Highway and Transportation Department, Little Rock JENNIFER COHAN, Secretary, Delaware DOT, Dover MALCOLM DOUGHERTY, Director, California Department of Transportation, Sacramento A. STEWART FOTHERINGHAM, Professor, School of Geographical Sciences and Urban Planning, Arizona State University, Tempe JOHN S. HALIKOWSKI, Director, Arizona DOT, Phoenix SUSAN HANSON, Distinguished University Professor Emerita, Graduate School of Geography, Clark University, Worcester, MA STEVE HEMINGER, Executive Director, Metropolitan Transportation Commission, Oakland, CA CHRIS T. HENDRICKSON, Hamerschlag Professor of Engineering, Carnegie Mellon University, Pittsburgh, PA JEFFREY D. HOLT, Managing Director, Power, Energy, and Infrastructure Group, BMO Capital Markets Corporation, New York S. JACK HU, Vice President for Research and J. Reid and Polly Anderson Professor of Manufacturing, University of Michigan, Ann Arbor ROGER B. HUFF, President, HGLC, LLC, Farmington Hills, MI GERALDINE KNATZ, Professor, Sol Price School of Public Policy, Viterbi School of Engineering, University of Southern California, Los Angeles YSELA LLORT, Consultant, Miami, FL MELINDA MCGRATH, Executive Director, Mississippi DOT, Jackson JAMES P. REDEKER, Commissioner, Connecticut DOT, Newington MARK L. ROSENBERG, Executive Director, The Task Force for Global Health, Inc., Decatur, GA KUMARES C. SINHA, Olson Distinguished Professor of Civil Engineering, Purdue University, West Lafayette, IN DANIEL SPERLING, Professor of Civil Engineering and Environmental Science and Policy; Director, Institute of Transportation Studies, University of California, Davis KIRK T. STEUDLE, Director, Michigan DOT, Lansing GARY C. THOMAS, President and Executive Director, Dallas Area Rapid Transit, Dallas, TX PAT THOMAS, Senior Vice President of State Government Affairs, United Parcel Service, Washington, DC KATHERINE F. TURNBULL, Executive Associate Director and Research Scientist, Texas A&M Transportation Institute, College Station DEAN WISE, Vice President of Network Strategy, Burlington Northern Santa Fe Railway, Fort Worth, TX EX OFFICIO MEMBERS THOMAS P. BOSTICK (Lieutenant General, U.S. Army), Chief of Engineers and Commanding General, U.S. Army Corps of Engineers, Washington, DC JAMES C. CARD (Vice Admiral, U.S. Coast Guard, retired), Maritime Consultant, The Woodlands, Texas, and Chair, TRB Marine Board T. F. SCOTT DARLING III, Acting Administrator and Chief Counsel, Federal Motor Carrier Safety Administration, U.S. DOT MARIE THERESE DOMINGUEZ, Administrator, Pipeline and Hazardous Materials Safety Administration, U.S. DOT SARAH FEINBERG, Administrator, Federal Railroad Administration, U.S. DOT CAROLYN FLOWERS, Acting Administrator, Federal Transit Administration, U.S. DOT LEROY GISHI, Chief, Division of Transportation, Bureau of Indian Affairs, U.S. Department of the Interior, Washington, DC JOHN T. GRAY II, Senior Vice President, Policy and Economics, Association of American Railroads, Washington, DC MICHAEL P. HUERTA, Administrator, Federal Aviation Administration, U.S. DOT PAUL N. JAENICHEN, SR., Administrator, Maritime Administration, U.S. DOT BEVAN B. KIRLEY, Research Associate, University of North Carolina Highway Safety Research Center, Chapel Hill, and Chair, TRB Young Members Council MICHAEL P. MELANIPHY, President and CEO, American Public Transportation Association, Washington, DC GREGORY G. NADEAU, Administrator, Federal Highway Administration, U.S. DOT WAYNE NASTRI, Acting Executive Officer, South Coast Air Quality Management District, Diamond Bar, CA MARK R. ROSEKIND, Administrator, National Highway Traffic Safety Administration, U.S. DOT CRAIG A. RUTLAND, U.S. Air Force Pavement Engineer, U.S. Air Force Civil Engineer Center, Tyndall Air Force Base, FL REUBEN SARKAR, Deputy Assistant Secretary for Transportation, U.S. Department of Energy GREGORY D. WINFREE, Assistant Secretary for Research and Technology, Office of the Secretary, U.S. DOT FREDERICK G. (BUD) WRIGHT, Executive Director, American Association of State Highway and Transportation Officials, Washington, DC PAUL F. ZUKUNFT (Admiral, U.S. Coast Guard), Commandant, U.S. Coast Guard, U.S. Department of Homeland Security * Membership as of April 2016.
TRANSPORTATION RESEARCH BOARD WASHINGTON, D.C. 2016 www.TRB.org NAT IONAL COOPERAT IVE H IGHWAY RESEARCH PROGRAM NCHRP SYNTHESIS 496 Research Sponsored by the American Association of State Highway and Transportation Officials in Cooperation with the Federal Highway Administration SubScriber categorieS Highways â¢ Geotechnology â¢ Hydraulics and Hydrology Minimizing Roadway Embankment Damage from Flooding A Synthesis of Highway Practice conSultantS Jean-Louis Briaud and Layal Maddah Texas A&M University College Station, Texas
NATIONAL COOPERATIVE HIGHWAY RESEARCH PROGRAM Systematic, well-designed research provides the most effective approach to the solution of many problems facing highway administra- tors and engineers. Often, highway problems are of local interest and can best be studied by highway departments individually or in coop- eration with their state universities and others. However, the accelerat- ing 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 Offi- cials initiated in 1962 an objective national highway research pro- gram employing modern scientific techniques. This program is sup- ported on a continuing basis by funds from participating member states of the Association and it receives the full cooperation and sup- port of the Federal Highway Administration, United States Depart- ment of Transportation. The Transportation Research Board of the National Research Coun- cil was requested by the Association to administer the research pro- gram 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 communication and cooperation with federal, state, and local governmental agencies, universities, and industry; its relationship to the National Research Council is an insurance of objec- tivity; 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 Coop- erative 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. NCHRP SYNTHESIS 496 Project 20-05 (Topic 46-16) ISSN 0547-5570 ISBN 978-0-309-38973-0 Library of Congress Control No. 2016941202 Â© 2016 National Academy of Sciences. All rights reserved. COPYRIGHT INFORMATION Authors herein are responsible for the authenticity of their manuscripts 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 repro- duce material in this publication for classroom and not-for-profit pur- poses. Permission is given with the understanding that none of the material will be used to imply TRB, AASHTO, FAA, FHWA, FMSCA, 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 development or reproduced material. For other uses of the material, request permission from CRP. NOTICE The report was reviewed by the technical panel and accepted for publi- cation according to procedures established and overseen by the Trans- portation 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 neces- sarily those of the Transportation Research Board; the National Acade- mies of Sciences, Engineering, and Medicine; or the program sponsors. The Transportation Research Board; the National Academies of Sci- ences, 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 conÂ¬sidered essential to the object of the report. 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
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.
TOPIC PANEL 46-16 DARYOUSH D. âDAVIDâ AHDOUT, New Jersey Department of Transportation, Trenton J.T. ANDERSON, Minnesota Department of Transportation, Crookston STUART DAVIS, U.S. Army Corps of Engineers, Alexandria, VA LINDA NARIGON, Iowa Department of Transportation, Ames KEVIN E. WHITE, E. L. Robinson Engineering, Columbus, OH WESLEY C. ZECH, Auburn University, Auburn, AL JON K. ZIRKLE, Tennessee Department of Transportation, Nashville JOE KROLAK, Federal Highway Administration (Liaison) JIM SHERWOOD, Federal Highway Administration (Liaison) SYNTHESIS STUDIES STAFF STEPHEN R. GODWIN, Director for Studies and Special Programs JON M. WILLIAMS, Program Director, IDEA and Synthesis Studies JO ALLEN GAUSE, Senior Program Officer GAIL R. STABA, Senior Program Officer DONNA L. VLASAK, Senior Program Officer TANYA M. ZWAHLEN, Consultant DON TIPPMAN, Senior Editor CHERYL KEITH, Senior Program Assistant DEMISHA WILLIAMS, Senior Program Assistant DEBBIE IRVIN, Program Associate COOPERATIVE RESEARCH PROGRAMS STAFF CHRISTOPHER W. JENKS, Director, Cooperative Research Programs CHRISTOPHER HEDGES, Manager, National Cooperative Highway Research Program EILEEN P. DELANEY, Director of Publications NCHRP COMMITTEE FOR PROJECT 20-05 CHAIR BRIAN A. BLANCHARD, Florida Department of Transportation MEMBERS STUART D. ANDERSON, Texas A&M University SOCORRO âCOCOâ BRISENO, California Department of Transportation DAVID M. JARED, Georgia Department of Transportation CYNTHIA L. JONES, Ohio Department of Transportation MALCOLM T. KERLEY, NXL, Richmond, Virginia JOHN M. MASON, JR., Auburn University ROGER C. OLSON, Bloomington, Minnesota BENJAMIN T. ORSBON, South Dakota Department of Transportation RANDALL R. âRANDYâ PARK, Utah Department of Transportation ROBERT L. SACK, New York State Department of Transportation FRANCINE SHAW WHITSON, Federal Highway Administration JOYCE N. TAYLOR, Maine Department of Transportation FHWA LIAISON JACK JERNIGAN TRB LIAISON STEPHEN F. MAHER Cover figures (clockwise from top left): Damage limited to the removal of performance turf and topsoil after armoring (Courtesy: Florida DOT); construction of stabilized roadway section (Courtesy: Florida DOT); damage from Hurricane Dennis (2005) along US-98, Franklin County, Florida (Courtesy: Florida DOT); installation of riprap placed over geotextile and then paved over (TH-9 south of Ada; Courtesy: Minnesota DOT).
ACKNOWLEDGMENTS: The authors wish to thank the members of the NCHRP panel and the NCHRP Synthesis staff: J.T. Anderson, P.E., Stuart Davis, Linda Narigon, P.E., Kevin E. White, P.E., Wesley C. Zech, Jon K. Zirkle, P.E., Joe Krolak, P.E., Jim Sherwood, Stephen F. Maher, Daryoush D. âDavidâ Ahdout, and Tanya M. Zwahlen, AICP. The authors would also like to thank all the DOT engineers who responded to the survey, with special thanks to the DOT engineers and FHWA interviewees: Steven Griffin, P.E., CFM (CDOT), Steven Humphrey, P.E. LEED A.P. (CDOT), George Rudy Hermann, Ph.D., P.E., P.H. D.WRE CFM (TXDOT), Kirk Douglas, P.E. (WVDOT), Karen Higgins, P.E. (GDOT), Greg Rogers, P.E. (FDOT), Jonathan A. Eboli, P.E. (PENNDOT), William R. Bailey, P.E. (WYDOT), Cornelius Barmer, P.E. (Maryland DOT), Scott Hogan, P.E. (FHWA), Stephen M. Sisson, P.E. (Delaware DOT), Suzan Beck, P.E. (GDOT), and Ms. Mary Cooley (GDOT).
Highway administrators, engineers, and researchers often face problems for which information already exists, either in documented form or as undocumented experience and practice. This information may be fragmented, scattered, and unevaluated. As a con- sequence, 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 evaluating such useful information and to make it available to the entire highway commu- nity, the American Association of State Highway and Transportation Officialsâthrough the mechanism of the National Cooperative Highway Research Programâauthorized the Transportation Research Board to undertake a continuing study. This study, NCHRP Proj- ect 20-5, âSynthesis of Information Related to Highway Problems,â searches out and syn- thesizes 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. NCHRP Synthesis 496 is a state-of-the-practice report on how the transportation com- munity is protecting roadways and mitigating damage from inundation and overtopping. In the absence of standard guidance, this report highlights major issues and design compo- nents specific to roadway embankment damage from flooding. It documents the mechanics of damage to the embankment and pavement, and the analysis tools available. The probable failure mechanisms are identified and various design approaches and repair countermea- sures are highlighted. The information presented in the synthesis is based on a review of the related literature, a survey of current practice, and a series of telephone interviews with state departments of transportation. Jean-Louis Briaud and Layal Maddah, Texas A&M University, College Station, Texas, collected and synthesized the information and wrote the report. The members of the topic panel are acknowledged on the preceding page. This synthesis is an immediately use- ful document that records the practices that were acceptable within the limitations of the knowledge available at the time of its preparation. As progress in research and practice continues, new knowledge will be added to that now at hand. FOREWORD PREFACE Tanya M. Zwahlen Consultant Transportation Research Board
CONTENTS 1 SUMMARY 4 CHAPTER ONE INTRODUCTION Introduction, 4 Study Approach, 4 Roadway Embankments versus Levees, 4 Coastal versus Riverine Embankments, 5 Summary, 7 8 CHAPTER TWO FAILURE MODES Introduction, 8 Common Failure Modes, 8 Overtopping, 8 Softening as a Result of Saturation, 11 Underseepage, 11 Wave Erosion, 12 Through-Seepage and Internal Erosion, 12 Lateral Sliding on Foundations, 12 Other Modes of Failure: Pavements and Culverts, 13 Summary, 13 14 CHAPTER THREE CASE EXAMPLES Introduction, 14 Wave Erosion of a Coastal Highway, Florida, 14 Overtopping Erosion of a Riverine Highway, Wyoming, 16 Damage Resulting from Overtopping and Wave Action of Riverine Highways, Minnesota, 17 Damage in Canyon Environments, Colorado, 20 MD-24 Deer Creek Stream Stabilization, Maryland, 23 Kimsey Run Project, West Virginia, 24 Summary, 26 27 CHAPTER FOUR HYDROLOGIC AND HYDRAULIC FACTORS Introduction, 27 Useful Concepts, 27 Hydrological Methods and Considerations, 30 Hydraulic Methods and Considerations, 33 Flow Discharge and Velocity Equations, 33 Case I: Flood or Storm Surge Overtopping, 33 Case II: Wave Overtopping, 36 Summary, 38 39 CHAPTER FIVE GEOTECHNICAL AND GEOLOGICAL FACTORS Introduction, 39 Geotechnical Considerations, 39 Geological Considerations, 43 Design Considerations for Failure Modes, 44 Summary, 52
x 53 CHAPTER SIX LEGAL, REGULATORY, AND FUNDING ASPECTS Introduction, 53 Designing Embankments as Levees, 53 Freeboard Issue, 53 Funding Options, 54 Preparedness, 55 Special Considerations, 56 Summary, 56 57 CHAPTER SEVEN PROBABILITY AND RISK Deterministic, Probabilistic, and Risk Approaches, 57 Advantages and Drawbacks of the Deterministic Approach, 57 Advantages and Drawbacks of the Probabilistic Approach, 57 Advantages and Drawbacks of the Risk Approach, 58 Design Flood and Associated Probability of Exceedance, 59 Summary, 59 60 CHAPTER EIGHT SUMMARY OF SURVEY RESULTS Introduction, 60 Case Examples, 60 Documents Used in Current Practice, 62 Modes of Failure, 63 Geological Considerations, 63 Hydraulic and Hydrologic Considerations, 64 Geotechnical Considerations, 65 Design and Construction Considerations, 65 Protection Techniques, 65 Probability and Risk, 66 Decision-Making Process and Funding, 66 Current and Future Research Areas, 67 Summary, 67 68 CHAPTER NINE DESIGN CONSIDERATIONS Introduction, 68 Choose the Design Flood, 68 Overtopping, 69 Seepage Through the Embankment, 69 Seepage Under the Embankment, 69 Wave Erosion, 69 Softening by Saturation, 70 Lateral Sliding, 70 Culverts, 70 Pavements, 70 Summary, 71 72 CHAPTER TEN COUNTERMEASURES, MAINTENANCE, AND REPAIR Introduction, 72 Overtopping, 72 Through-Seepage, 74 Underseepage-Seepage, 74 Wave-Erosion, 74 Softening by Saturation, 74 Lateral Sliding, 74 Culverts, 74