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TRANSPORTATION RESEARCH BOARD 2024 EXECUTIVE COMMITTEE*
OFFICERS
CHAIR: Carol A. Lewis, Professor, Transportation Studies, Texas Southern University, Houston
VICE CHAIR: Leslie S. Richards, General Manager, Southeastern Pennsylvania Transportation Authority (SEPTA), Philadelphia
EXECUTIVE DIRECTOR: Victoria Sheehan, Transportation Research Board, Washington, DC
MEMBERS
Michael F. Ableson, CEO, Arrival Automotive–North America, Detroit, MI
James F. Albaugh, President and CEO, The Boeing Company (retired), Scottsdale, AZ
Carlos M. Braceras, Executive Director, Utah Department of Transportation, Salt Lake City
Douglas C. Ceva, Vice President, Customer Lead Solutions, Prologis, Inc., Jupiter, FL
Nancy Daubenberger, Commissioner of Transportation, Minnesota Department of Transportation, St. Paul
Marie Therese Dominguez, Commissioner, New York State Department of Transportation, Albany
Garrett Eucalitto, Commissioner, Connecticut Department of Transportation, Newington
Chris T. Hendrickson, Hamerschlag University Professor of Engineering Emeritus, Carnegie Mellon University, Pittsburgh, PA
Randell Iwasaki, President and CEO, Iwasaki Consulting Services, Walnut Creek, CA
Ashby Johnson, Executive Director, Capital Area Metropolitan Planning Organization (CAMPO), Austin, TX
Joel M. Jundt, Secretary of Transportation, South Dakota Department of Transportation, Pierre
Hani S. Mahmassani, W.A. Patterson Distinguished Chair in Transportation; Director, Transportation Center, Northwestern University, Evanston, IL
Scott C. Marler, Director, Iowa Department of Transportation, Ames
Ricardo Martinez, Adjunct Professor of Emergency Medicine, Emory University School of Medicine, Decatur, GA
Michael R. McClellan, Vice President, Strategic Planning, Norfolk Southern Corporation, Norfolk, VA
Russell McMurry, Commissioner, Georgia Department of Transportation, Atlanta
Craig E. Philip, Research Professor and Director, VECTOR, Department of Civil and Environmental Engineering, Vanderbilt University, Nashville, TN
Steward T.A. Pickett, Distinguished Senior Scientist, Cary Institute of Ecosystem Studies, Millbrook, NY
Susan A. Shaheen, Professor and Co-director, Transportation Sustainability Research Center, University of California, Berkeley
Marc Williams, Executive Director, Texas Department of Transportation, Austin
EX OFFICIO MEMBERS
Michael R. Berube, Deputy Assistant Secretary for Sustainable Transportation, U.S. Department of Energy, Washington, DC
Shailen Bhatt, Administrator, Federal Highway Administration, U.S. Department of Transportation, Washington, DC
Amit Bose, Administrator, Federal Railroad Administration, Washington, DC
Tristan Brown, Deputy Administrator, Pipeline and Hazardous Materials Safety Administration, U.S. Department of Transportation, Washington, DC
Steven Cliff, Executive Officer, California Air Resources Board, Sacramento
Rand Ghayad, Senior Vice President, Association of American Railroads, Washington, DC
LeRoy Gishi, Chief, Division of Transportation, Bureau of Indian Affairs, U.S. Department of the Interior, Germantown, MD
William H. Graham, Jr. (Major General, U.S. Army), Deputy Commanding General for Civil and Emergency Operations, U.S. Army Corps of Engineers, Washington, DC
Robert C. Hampshire, Deputy Assistant Secretary for Research and Technology, U.S. Department of Transportation, Washington, DC
Sue Lawless, Acting Deputy Administrator, Federal Motor Carrier Safety Administration, Washington, DC
Niloo Parvashtiani, Engineer, Mobility Consultant Solutions, Iteris Inc., Fairfax, VA, and Chair, TRB Young Members Coordinating Council
Sophie Shulman, Acting Administrator, National Highway Traffic Safety Administration, Washington, DC
Karl Simon, Director, Transportation and Climate Division, U.S. Environmental Protection Agency, Washington, DC
Paul P. Skoutelas, President and CEO, American Public Transportation Association, Washington, DC
Polly Trottenberg, Deputy Secretary of Transportation and Acting Administrator, Federal Aviation Administration, U.S. Department of Transportation, Washington, DC
Jim Tymon, Executive Director, American Association of State Highway and Transportation Officials, Washington, DC
Veronica Vanterpool, Acting Administrator, Federal Transit Administration, Washington, DC
___________________
* Membership as of May 2024.
NATIONAL COOPERATIVE HIGHWAY RESEARCH PROGRAM
NCHRP RESEARCH REPORT 1112
Design of Piles for Downdrag
Richard A. Coffman
Johnathan D. Blanchard
UNIVERSITY OF ARKANSAS
Fayetteville, AR
Armin W. Stuedlein
Amalesh Jana
OREGON STATE UNIVERSITY
Corvallis, OR
Aaron S. Budge
MINNESOTA STATE UNIVERSITY, MANKATO
Mankato, MN
Subscriber Categories
Highways • Bridges and Other Structures • Geotechnology
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, and implementable research is the most effective way to solve many problems facing state departments of transportation (DOTs) administrators and engineers. Often, highway problems are of local or regional interest and can best be studied by state DOTs individually or in cooperation with their state universities and others. However, the accelerating growth of highway transportation results in increasingly complex problems of wide interest 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 initiated an objective national highway research program using modern scientific techniques—the 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 (FHWA), United States Department of Transportation, under Agreement No. 693JJ31950003.
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 TRB’s recognized objectivity and understanding of modern research practices. TRB is uniquely suited for this purpose for many reasons: TRB maintains an extensive committee 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, universities, and industry; TRB’s relationship to the National Academies is an insurance of objectivity; and TRB maintains a full-time staff of specialists in highway 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 transportation departments, by committees of AASHTO, and by the FHWA. Topics of the highest merit are selected by the AASHTO Special Committee on Research and Innovation (R&I), and each year R&I’s recommendations are proposed to the AASHTO Board of Directors and the National 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 National Academies 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.
NCHRP RESEARCH REPORT 1112
Project 12-116A
ISSN 2572-3766 (Print)
ISSN 2572-3774 (Online)
ISBN 978-0-309-70990-3
Library of Congress Control Number 2024939356
© 2024 by the National Academy of Sciences. National Academies of Sciences, Engineering, and Medicine and the graphical logo are trademarks of the National Academy of Sciences. All rights reserved.
COPYRIGHT INFORMATION
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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, APTA, FAA, FHWA, FTA, GHSA, or NHTSA 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; the FHWA; or the program sponsors.
The Transportation Research Board does not develop, issue, or publish standards or specifications. The Transportation Research Board manages applied research projects which provide the scientific foundation that may be used by Transportation Research Board sponsors, industry associations, or other organizations as the basis for revised practices, procedures, or specifications.
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COOPERATIVE RESEARCH PROGRAMS
CRP STAFF FOR NCHRP RESEARCH REPORT 1112
Waseem Dekelbab, Deputy Director, Cooperative Research Programs, and Manager, National Cooperative Highway Research Program
Ahmad Abu-Hawash, Senior Program Officer
Sheila A. Moore, Program Associate
Natalie Barnes, Director of Publications
Heather DiAngelis, Associate Director of Publications
NCHRP PROJECT 12-116A PANEL
Field of Design—Area of Bridges
Jon E. Bischoff, Utah Department of Transportation, Salt Lake City, UT (Chair)
Nathalia Rodriguez Chandler, South Carolina Department of Transportation, Columbia, SC
Scott Hidden, North Carolina Department of Transportation, Raleigh, NC
Tim E. Huff, Tennessee Technological University, Cookeville, TN
Nora Kyo, California Department of Transportation, Sacramento, CA
Richard Pratt, Alaska Department of Transportation, (retired), Juneau, AK
Ryan Snook, Michigan Department of Transportation, Lansing, MI
Derrick David Dasenbrock, FHWA Liaison
FOREWORD
By Ahmad Abu-Hawash
Staff Officer
Transportation Research Board
NCHRP Research Report 1112: Design of Piles for Downdrag presents procedures for determining downdrag loads used in the design of bridge piles. The procedures were developed based on an extensive review of the state of practice and a collection of existing field test data. The research findings will be used by geotechnical engineers responsible for designing bridge foundations for state departments of transportation.
The AASHTO LRFD [Load and Resistance Factor Design] Bridge Design Specifications (BDS) recognizes that piles in settling soil experience downdrag forces from negative skin friction and may also move downward with the adjacent soil. Many bridges are constructed in areas where there is compressible soil or liquefiable soil, which necessitates the consideration of downdrag forces and associated settlement. Downdrag for static and seismic conditions has increasingly placed greater demands on existing and new foundations and also led to higher construction costs. Therefore, there was an immediate need to review the fundamental behavior of piles subject to downdrag and propose design requirements for the implementation of the neutral plane method for the evaluation of downdrag and the static and seismic design of piles.
Under NCHRP Project 12-116A, “Proposed AASHTO Specifications for Design of Piles for Downdrag,” the University of Arkansas was asked to (1) propose modifications to the bridge design requirements for the static and seismic design of piles for downdrag and (2) develop design examples to demonstrate the application of the proposed design requirements. The research team proposed draft language for consideration by AASHTO in the next update of the LRFD BDS and provided analysis and design examples to illustrate the proposed updates.
In addition to this report, NCHRP Web-Only Document 398: Pile Design for Downdrag: Examples and Supporting Material is available on the National Academies Press website (nap.nationalacademies.org) by searching for NCHRP Web-Only Document 398.
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