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NATIONAL
NCHRP
REPORT 515
COOPERATIVE
HIGHWAY
RESEARCH
PROGRAM
Portable Scour
Monitoring Equipment
OCR for page R2
TRANSPORTATION RESEARCH BOARD EXECUTIVE COMMITTEE 2003 (Membership as of October 2003)
OFFICERS
Chair: Genevieve Giuliano, Director, Metrans Transportation Center, and Professor, School of Policy, Planning, and Development,
University of Southern California, Los Angeles
Vice Chair: Michael S. Townes, President and CEO, Hampton Roads Transit, Hampton, VA
Executive Director: Robert E. Skinner, Jr., Transportation Research Board
MEMBERS
MICHAEL W. BEHRENS, Executive Director, Texas DOT
JOSEPH H. BOARDMAN, Commissioner, New York State DOT
SARAH C. CAMPBELL, President, TransManagement, Inc., Washington, DC
E. DEAN CARLSON, President, Carlson Associates, Topeka, KS
JOANNE F. CASEY, President and CEO, Intermodal Association of North America
JAMES C. CODELL III, Secretary, Kentucky Transportation Cabinet
JOHN L. CRAIG, Director, Nebraska Department of Roads
BERNARD S. GROSECLOSE, JR., President and CEO, South Carolina State Ports Authority
SUSAN HANSON, Landry University Professor of Geography, Graduate School of Geography, Clark University
LESTER A. HOEL, L. A. Lacy Distinguished Professor of Engineering, Department of Civil Engineering, University of Virginia
HENRY L. HUNGERBEELER, Director, Missouri DOT
ADIB K. KANAFANI, Cahill Professor and Chairman, Department of Civil and Environmental Engineering, University of California
at Berkeley
RONALD F. KIRBY, Director of Transportation Planning, Metropolitan Washington Council of Governments
HERBERT S. LEVINSON, Principal, Herbert S. Levinson Transportation Consultant, New Haven, CT
MICHAEL D. MEYER, Professor, School of Civil and Environmental Engineering, Georgia Institute of Technology
JEFF P. MORALES, Director of Transportation, California DOT
KAM MOVASSAGHI, Secretary of Transportation, Louisiana Department of Transportation and Development
CAROL A. MURRAY, Commissioner, New Hampshire DOT
DAVID PLAVIN, President, Airports Council International, Washington, DC
JOHN REBENSDORF, Vice President, Network and Service Planning, Union Pacific Railroad Co., Omaha, NE
CATHERINE L. ROSS, Harry West Chair of Quality Growth and Regional Development, College of Architecture, Georgia Institute of
Technology
JOHN M. SAMUELS, Senior Vice President, Operations, Planning and Support, Norfolk Southern Corporation, Norfolk, VA
PAUL P. SKOUTELAS, CEO, Port Authority of Allegheny County, Pittsburgh, PA
MARTIN WACHS, Director, Institute of Transportation Studies, University of California at Berkeley
MICHAEL W. WICKHAM, Chairman, Roadway Corporation, Akron, OH
MARION C. BLAKEY, Federal Aviation Administrator, U.S.DOT (ex officio)
SAMUEL G. BONASSO, Acting Administrator, Research and Special Programs Administration, U.S.DOT (ex officio)
REBECCA M. BREWSTER, President and COO, American Transportation Research Institute, Smyrna, GA (ex officio)
THOMAS H. COLLINS (Adm., U.S. Coast Guard), Commandant, U.S. Coast Guard (ex officio)
JENNIFER L. DORN, Federal Transit Administrator, U.S.DOT (ex officio)
ROBERT B. FLOWERS (Lt. Gen., U.S. Army), Chief of Engineers and Commander, U.S. Army Corps of Engineers (ex officio)
EDWARD R. HAMBERGER, President and CEO, Association of American Railroads (ex officio)
JOHN C. HORSLEY, Executive Director, American Association of State Highway and Transportation Officials (ex officio)
ROGER L. KING, Chief Applications Technologist, National Aeronautics and Space Administration (ex officio)
ROBERT S. KIRK, Director, Office of Advanced Automotive Technologies, U.S. Department of Energy (ex officio)
RICK KOWALEWSKI, Acting Director, Bureau of Transportation Statistics, U.S.DOT (ex officio)
WILLIAM W. MILLAR, President, American Public Transportation Association (ex officio)
MARY E. PETERS, Federal Highway Administrator, U.S.DOT (ex officio)
SUZANNE RUDZINSKI, Director, Transportation and Regional Programs, U.S. Environmental Protection Agency (ex officio)
JEFFREY W. RUNGE, National Highway Traffic Safety Administrator, U.S.DOT (ex officio)
ALLAN RUTTER, Federal Railroad Administrator, U.S.DOT (ex officio)
ANNETTE M. SANDBERG, Federal Motor Carrier Safety Administrator, U.S.DOT (ex officio)
WILLIAM G. SCHUBERT, Maritime Administrator, U.S.DOT (ex officio)
NATIONAL COOPERATIVE HIGHWAY RESEARCH PROGRAM
Transportation Research Board Executive Committee Subcommittee for NCHRP
GENEVIEVE GIULIANO, University of Southern California, MARY E. PETERS, Federal Highway Administration
Los Angeles (Chair) ROBERT E. SKINNER, JR., Transportation Research Board
E. DEAN CARLSON, Carlson Associates, Topeka, KS MICHAEL S. TOWNES, Hampton Roads Transit, Hampton, VA
LESTER A. HOEL, University of Virginia
JOHN C. HORSLEY, American Association of State Highway and
Transportation Officials
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NATIONAL COOPERATIVE HIGHWAY RESEARCH PROGRAM
NCHRP REPORT 515
Portable Scour Monitoring Equipment
JAMES D. SCHALL, PH.D.
Ayres Associates
Fort Collins, CO
AND
G. R. PRICE
ETI Instrument Systems
Fort Collins, CO
S UBJECT A REAS
Bridges, Other Structures, and Hydraulics and Hydrology · Soils, Geology, and Foundations · Maintenance
Research Sponsored by the American Association of State Highway and Transportation Officials
in Cooperation with the Federal Highway Administration
TRANSPORTATION RESEARCH BOARD
WASHINGTON, D.C.
2004
www.TRB.org
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NATIONAL COOPERATIVE HIGHWAY RESEARCH NCHRP REPORT 515
PROGRAM
Systematic, well-designed research provides the most effective Project C21-07 FY 2000
approach to the solution of many problems facing highway
administrators and engineers. Often, highway problems are of local ISSN 0077-5614
interest and can best be studied by highway departments ISBN 0-309-08784-8
individually or in cooperation with their state universities and
Library of Congress Control Number 2003116139
others. However, the accelerating growth of highway transportation
develops increasingly complex problems of wide interest to © 2004 Transportation Research Board
highway authorities. These problems are best studied through a
coordinated program of cooperative research. Price $21.00
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 NOTICE
Department of Transportation.
The project that is the subject of this report was a part of the National Cooperative
The Transportation Research Board of the National Academies
Highway Research Program conducted by the Transportation Research Board with the
was requested by the Association to administer the research
approval of the Governing Board of the National Research Council. Such approval
program because of the Board's recognized objectivity and reflects the Governing Board's judgment that the program concerned is of national
understanding of modern research practices. The Board is uniquely importance and appropriate with respect to both the purposes and resources of the
suited for this purpose as it maintains an extensive committee National Research Council.
structure from which authorities on any highway transportation
The members of the technical committee selected to monitor this project and to review
subject may be drawn; it possesses avenues of communications and
this report were chosen for recognized scholarly competence and with due
cooperation with federal, state and local governmental agencies, consideration for the balance of disciplines appropriate to the project. The opinions and
universities, and industry; its relationship to the National Research conclusions expressed or implied are those of the research agency that performed the
Council is an insurance of objectivity; it maintains a full-time research, and, while they have been accepted as appropriate by the technical committee,
research correlation staff of specialists in highway transportation they are not necessarily those of the Transportation Research Board, the National
matters to bring the findings of research directly to those who are in Research Council, the American Association of State Highway and Transportation
a position to use them. Officials, or the Federal Highway Administration, U.S. Department of Transportation.
The program is developed on the basis of research needs Each report is reviewed and accepted for publication by the technical committee
identified by chief administrators of the highway and transportation according to procedures established and monitored by the Transportation Research
departments and by committees of AASHTO. Each year, specific Board Executive Committee and the Governing Board of the National Research
areas of research needs to be included in the program are proposed Council.
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. Published reports of the
The needs for highway research are many, and the National
NATIONAL COOPERATIVE HIGHWAY RESEARCH PROGRAM
Cooperative Highway Research Program can make significant
contributions to the solution of highway transportation problems of are available from:
mutual concern to many responsible groups. The program,
however, is intended to complement rather than to substitute for or Transportation Research Board
duplicate other highway research programs. Business Office
500 Fifth Street, NW
Washington, DC 20001
and can be ordered through the Internet at:
Note: The Transportation Research Board of the National Academies, the
National Research Council, the Federal Highway Administration, the American
Association of State Highway and Transportation Officials, and the individual
http://www.national-academies.org/trb/bookstore
states participating in the National Cooperative Highway Research Program do
not endorse products or manufacturers. Trade or manufacturers' names appear
herein solely because they are considered essential to the object of this report. Printed in the United States of America
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The National Academy of Sciences is a private, nonprofit, self-perpetuating society of distinguished schol-
ars 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 techni-
cal matters. Dr. Bruce M. Alberts is president of the National Academy of Sciences.
The National Academy of Engineering was established in 1964, under the charter of the National Acad-
emy 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 achieve-
ments of engineers. Dr. William A. Wulf 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 Academy's purposes of furthering knowledge and
advising the federal government. Functioning in accordance with general policies determined by the Acad-
emy, 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 the Academies and the Institute
of Medicine. Dr. Bruce M. Alberts and Dr. William A. Wulf are chair and vice chair, respectively, of the
National Research Council.
The Transportation Research Board is a division of the National Research Council, which serves the
National Academy of Sciences and the National Academy of Engineering. The Board's mission is to promote
innovation and progress in transportation through research. In an objective and interdisciplinary setting, the
Board facilitates the sharing of information on transportation practice and policy by researchers and
practitioners; stimulates research and offers research management services that promote technical
excellence; provides expert advice on transportation policy and programs; and disseminates research
results broadly and encourages their implementation. The Board's varied activities annually engage more
than 4,000 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. www.TRB.org
www.national-academies.org
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COOPERATIVE RESEARCH PROGRAMS STAFF FOR NCHRP REPORT 515
ROBERT J. REILLY, Director, Cooperative Research Programs
CRAWFORD F. JENCKS, Manager, NCHRP
TIMOTHY G. HESS, Senior Program Officer
EILEEN P. DELANEY, Managing Editor
HILARY FREER, Associate Editor II
NCHRP PROJECT E21-7 PANEL
Field of Soils and Geology--Area of Testing and Instrumentation
DAVID S. MUELLER, US Geological Survey, Louisville, KY (Chair)
PETER J. BOSSCHER, University of Wisconsin--Madison
MICHAEL E. COOGAN, Arkansas SHTD
BILL DUVALL, Georgia DOT
THOMAS J. HARRINGTON, California DOT
ANDREA C. H. HENDRICKSON, Minnesota DOT
ROLLIN H. HOTCHKISS, Washington State University
JEFFREY KEATON, AMEC Earth & Environmental Inc., Anaheim, CA
WILLIAM OLIVA, Wisconsin DOT
J. STERLING JONES, FHWA Liaison Representative
G. P. JAYAPRAKASH, TRB Liaison Represnetative
AUTHOR ACKNOWLEDGMENTS
The research reported herein was performed under National University. Mr. Horatio Garza, Shop Foreman, provided many
Cooperative Highway Research Program (NCHRP) Project 21-07 ideas and suggestions.
by Ayres Associates, Inc., Fort Collins, Colorado. Dr. James D. A special acknowledgment is made to state transportation agen-
Schall served as Principal Investigator. He was assisted by Dr. Dave cies in Colorado, Alabama, Idaho, Minnesota, Missouri, and Wis-
Zachman, and Mr. John Batka. Mr. Jerry Price and Mr. Don Hor- consin for their assistance in locating field test sites and providing
ton, Instrumentation Engineers, ETI Instrument Systems, Fort staff support, including traffic control, during data collection.
Collins, Colorado, supported Ayres Associates in the specialized The participation, advice, and support of the NCHRP panel mem-
areas of instrumentation and data collection. Machine shop services bers throughout this project are gratefully acknowledged.
were provided by the Engineering Research Center, Colorado State
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This report presents the findings of a research project undertaken to develop
FOREWORD portable scour monitoring equipment for measuring streambed elevations at bridge
By Timothy G. Hess foundations during flood conditions. The report provides specific fabrication and oper-
Staff Officer ation guidance for a portable scour monitoring device. The fabrication guidance is of
Transportation Research sufficient detail to allow a highway agency to build a similar device. The report
Board describes the results of detailed testing of the scour monitoring device at ten bridge sites
in seven different states. This report will be of immediate interest to bridge engineers
and bridge operation and maintenance personnel with responsibility for determining
the safety of bridge foundations during flood events.
Scour monitoring at bridges is often necessary for protecting the traveling public
during floods. Although fixed scour monitoring equipment has been developed and is
readily available, it is not feasible to install fixed scour monitoring equipment on all
bridges. Each year, many bridges are subjected to severe flood conditions and scour.
Decisions about bridge closure are often based on streambed elevations around piers
and abutments measured with portable scour monitoring equipment such as weights
and echo sounders. Although existing portable monitoring equipment is adequate in
some situations, many common field situations occur where existing equipment is not
adequate. Common scour monitoring problems can be separated into two categories:
difficult flow conditions (e.g., high velocity, air entrainment in the water column, and
high sediment concentrations) and difficult site conditions (e.g., high bridges, low
clearance under bridges, floating debris, and ice accumulations). These problems are
common during flood events, when the need for streambed elevation information is
most critical. There is a need for a portable scour monitoring device that can be used
to measure streambed elevations around bridge foundations in difficult flow and site
conditions during flood events. The inability to assess the safety of bridges during flood
events accurately has resulted in some bridges being closed unnecessarily, causing traf-
fic delays and increased expenses, while other bridges that should have been closed
were not, resulting in increased risk to the public.
Under NCHRP Project 21-07, Ayres Associates developed a portable scour mon-
itoring device for measuring streambed elevations and the depth of scour around bridge
piers and abutments during flood events. The research team reviewed the literature to
identify existing technology suitable for use in developing a scour monitoring device.
Key criteria in technology selection were cost and portability. Feasible alternatives
were investigated and the most promising alternative was selected for development.
The research resulted in a scour monitoring device that was both portable and capable
of measuring scour during actual flood events and extreme conditions. The device can
be used at a wide variety of bridge geometries, including high bridges, bridges with
limited clearance, and bridges with large overhangs. A comprehensive data collection
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software package was developed to allow immediate access to the collected data and
the instantaneous plotting of channel section and scourhole bathymetry. The findings
of this research will significantly enhance the capabilities of highway agencies in
assessing the extent of bridge scour during flood events and making bridge closure
decisions with increased confidence.
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CONTENTS 1 SUMMARY
3 CHAPTER 1 Introduction and Research Approach
Problem Statement, 3
Research Objective, 3
Research Tasks, 4
Research Approach, 4
5 CHAPTER 2 Findings
Literature Search, 5
Feasible Alternatives, 10
Phase II Work Plan, 12
Prototype Development and Limited Testing, 13
Detailed Field Testing, 32
41 CHAPTER 3 Interpretation, Appraisal, and Applications
Introduction, 41
Interpretation and Appraisal, 41
Applications, 45
48 CHAPTER 4 Conclusions and Suggested Research
Conclusions, 48
Suggestions for Further Research, 48
50 REFERENCES
A-1 APPENDIX A: Users Manual
B-1 APPENDIX B: Field Testing Results