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NATIONAL NCHRP REPORT 697 COOPERATIVE HIGHWAY RESEARCH PROGRAM Design Guidelines for Increasing the Lateral Resistance of Highway-Bridge Pile Foundations by Improving Weak Soils
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TRANSPORTATION RESEARCH BOARD 2011 EXECUTIVE COMMITTEE* OFFICERS CHAIR: Neil J. Pedersen, Administrator, Maryland State Highway Administration, Baltimore VICE CHAIR: Sandra Rosenbloom, Professor of Planning, University of Arizona, Tucson EXECUTIVE DIRECTOR: Robert E. Skinner, Jr., Transportation Research Board MEMBERS J. Barry Barker, Executive Director, Transit Authority of River City, Louisville, KY Deborah H. Butler, Executive Vice President, Planning, and CIO, Norfolk Southern Corporation, Norfolk, VA William A.V. Clark, Professor, Department of Geography, University of California, Los Angeles Eugene A. Conti, Jr., Secretary of Transportation, North Carolina DOT, Raleigh James M. Crites, Executive Vice President of Operations, Dallas-Fort Worth International Airport, TX Paula J. Hammond, Secretary, Washington State DOT, Olympia Michael W. Hancock, Secretary, Kentucky Transportation Cabinet, Frankfort Adib K. Kanafani, Cahill Professor of Civil Engineering, University of California, Berkeley Michael P. Lewis, Director, Rhode Island DOT, Providence Susan Martinovich, Director, Nevada DOT, Carson City Michael R. Morris, Director of Transportation, North Central Texas Council of Governments, Arlington Tracy L. Rosser, Vice President, Regional General Manager, Wal-Mart Stores, Inc., Mandeville, LA Steven T. Scalzo, Chief Operating Officer, Marine Resources Group, Seattle, WA Henry G. (Gerry) Schwartz, Jr., Chairman (retired), Jacobs/Sverdrup Civil, Inc., St. Louis, MO Beverly A. Scott, General Manager and CEO, Metropolitan Atlanta Rapid Transit Authority, Atlanta, GA David Seltzer, Principal, Mercator Advisors LLC, Philadelphia, PA Lawrence A. Selzer, President and CEO, The Conservation Fund, Arlington, VA Kumares C. Sinha, Olson Distinguished Professor of Civil Engineering, Purdue University, West Lafayette, IN Thomas K. Sorel, Commissioner, Minnesota DOT, St. Paul Daniel Sperling, Professor of Civil Engineering and Environmental Science and Policy; Director, Institute of Transportation Studies; and Interim Director, Energy Efficiency Center, University of California, Davis Kirk T. Steudle, Director, Michigan DOT, Lansing Douglas W. Stotlar, President and CEO, Con-Way, Inc., Ann Arbor, MI C. Michael Walton, Ernest H. Cockrell Centennial Chair in Engineering, University of Texas, Austin EX OFFICIO MEMBERS Peter H. Appel, Administrator, Research and Innovative Technology Administration, U.S.DOT J. Randolph Babbitt, Administrator, Federal Aviation Administration, U.S.DOT Rebecca M. Brewster, President and COO, American Transportation Research Institute, Smyrna, GA Anne S. Ferro, Administrator, Federal Motor Carrier Safety Administration, U.S.DOT LeRoy Gishi, Chief, Division of Transportation, Bureau of Indian Affairs, U.S.DOT John T. Gray, Senior Vice President, Policy and Economics, Association of American Railroads, Washington, DC John C. Horsley, Executive Director, American Association of State Highway and Transportation Officials, Washington, DC David T. Matsuda, Deputy Administrator, Maritime Administration, U.S.DOT Victor M. Mendez, Administrator, Federal Highway Administration, U.S.DOT William W. Millar, President, American Public Transportation Association, Washington, DC Tara O'Toole, Under Secretary for Science and Technology, U.S. Department of Homeland Security, Washington, DC Robert J. Papp (Adm., U.S. Coast Guard), Commandant, U.S. Coast Guard, U.S. Department of Homeland Security, Washington, DC Cynthia L. Quarterman, Administrator, Pipeline and Hazardous Materials Safety Administration, U.S.DOT Peter M. Rogoff, Administrator, Federal Transit Administration, U.S.DOT David L. Strickland, Administrator, National Highway Traffic Safety Administration, U.S.DOT Joseph C. Szabo, Administrator, Federal Railroad Administration, U.S.DOT Polly Trottenberg, Assistant Secretary for Transportation Policy, U.S.DOT Robert L. Van Antwerp (Lt. Gen., U.S. Army), Chief of Engineers and Commanding General, U.S. Army Corps of Engineers, Washington, DC Barry R. Wallerstein, Executive Officer, South Coast Air Quality Management District, Diamond Bar, CA *Membership as of June 2011.
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NATIONAL COOPERATIVE HIGHWAY RESEARCH PROGRAM NCHRP REPORT 697 Design Guidelines for Increasing the Lateral Resistance of Highway-Bridge Pile Foundations by Improving Weak Soils Kyle Rollins BRIGHAM YOUNG UNIVERSITY Provo, UT Dan Brown DAN BROWN & ASSOCIATES Sequatchie, TN Subscriber Categories Bridges and Other Structures · Design · Geotechnology 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. 2011 www.TRB.org
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NATIONAL COOPERATIVE HIGHWAY NCHRP REPORT 697 RESEARCH PROGRAM Systematic, well-designed research provides the most effective Project 24-30 approach to the solution of many problems facing highway ISSN 0077-5614 administrators and engineers. Often, highway problems are of local ISBN 978-0-309-21341-7 interest and can best be studied by highway departments individually Library of Congress Control Number 2011934448 or in cooperation with their state universities and others. However, the © 2011 National Academy of Sciences. All rights reserved. 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 COPYRIGHT INFORMATION cooperative research. Authors herein are responsible for the authenticity of their materials and for obtaining In recognition of these needs, the highway administrators of the written permissions from publishers or persons who own the copyright to any previously American Association of State Highway and Transportation Officials published or copyrighted material used herein. initiated in 1962 an objective national highway research program Cooperative Research Programs (CRP) grants permission to reproduce material in this employing modern scientific techniques. This program is supported on 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, a continuing basis by funds from participating member states of the FMCSA, FTA, or Transit Development Corporation endorsement of a particular product, Association and it receives the full cooperation and support of the method, or practice. It is expected that those reproducing the material in this document for Federal Highway Administration, United States Department of 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 Transportation. from CRP. The Transportation Research Board of the National Academies was requested by the Association to administer the research program because of the Board's recognized objectivity and understanding of NOTICE modern research practices. The Board is uniquely suited for this purpose as it maintains an extensive committee structure from which 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 authorities on any highway transportation subject may be drawn; it the Governing Board of the National Research Council. possesses avenues of communications and cooperation with federal, The members of the technical panel selected to monitor this project and to review this state and local governmental agencies, universities, and industry; its report were chosen for their special competencies and with regard for appropriate balance. relationship to the National Research Council is an insurance of 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 objectivity; it maintains a full-time research correlation staff of by the Governing Board of the National Research Council. specialists in highway transportation matters to bring the findings of The opinions and conclusions expressed or implied in this report are those of the research directly to those who are in a position to use them. researchers who performed the research and are not necessarily those of the Transportation The program is developed on the basis of research needs identified Research Board, the National Research Council, or the program sponsors. by chief administrators of the highway and transportation departments The Transportation Research Board of the National Academies, the National Research and by committees of AASHTO. Each year, specific areas of research Council, and the sponsors of the National Cooperative Highway Research Program do not needs to be included in the program are proposed to the National endorse products or manufacturers. Trade or manufacturers' names appear herein solely because they are considered essential to the object of the report. 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
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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 Academy's 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 Board's 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
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COOPERATIVE RESEARCH PROGRAMS CRP STAFF FOR NCHRP REPORT 697 Christopher W. Jenks, Director, Cooperative Research Programs Crawford F. Jencks, Deputy Director, Cooperative Research Programs Andrew C. Lemer, Senior Program Officer Sheila A. Moore, Senior Program Assistant Eileen P. Delaney, Director of Publications Hilary Freer, Senior Editor NCHRP PROJECT 24-30 PANEL Field of Soils and Geology--Area of Mechanics and Foundations Jon E. Bischoff, Utah DOT, Salt Lake City, UT (Chair) Mark DeSalvatore, California DOT, Sacramento, CA Manoj B. Chopra, University of Central Florida, Orlando, FL Nicholas E. Harman, South Carolina DOT, Columbia, SC Michael G. Katona, Washington State University (Retired), Gig Harbor, WA Daehyeon Kim, Chosun University, Gwangju, Korea Lianyang Zhang, University of Arizona, Tucson, AZ Silas Nichols, FHWA Liaison G. P. Jayaprakash, TRB Liaison AUTHOR ACKNOWLEDGMENTS The research reported herein was performed under NCHRP Project 24-30 by the Department of Civil and Environmental Engineering at Brigham Young University (BYU) in Provo, Utah. Kyle M. Rollins, Ph.D., professor of civil and environmental engineering, was the project director and principal investiga- tor. Dan Brown, Ph.D., P.E., principal engineer at Dan Brown & Associates in Sequatchie, Tennessee, was co-principal investigator. The other authors of this report are Hubert Law, Ph.D., P.E., and Dr. Zhao (Joe) Chang, Ph.D., of Earth Mechanics Inc. of Fountain Valley, California. Matthew Adsero, Mark Herbst, Nathan Lemme, and Dustin Miner performed the field load testing reported in this study under the super- vision of Dr. Rollins of BYU with the assistance of David Anderson, chief technician for the Civil & Envi- ronmental Engineering Department at BYU.
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FOREWORD By Andrew C. Lemer Staff Officer Transportation Research Board NCHRP Report 697: Design Guidelines for Increasing the Lateral Resistance of Highway- Bridge Pile Foundations by Improving Weak Soils presents design guidance for strengthen- ing of soils to resist lateral forces on bridge pile foundations. Lateral loads may be produced by wave action, wind, seismic events, ship impact, or traffic. Strengthening of soil sur- rounding the upper portions of piles and pile groups--for example by compaction, replacement of native soil with granular material, or mixing of cement with soil--may be more cost-effective than driving additional piles and extending pile caps as ways to increase the bridge foundation's capacity to resist lateral forces associated with these loads. This report presents computational methods for assessing soil-strengthening options using finite-element analysis of single piles and pile groups and a simplified approach employ- ing commercially available software. The analysis methodology and design guidelines will be helpful to designers responsible for bridge foundations likely to be exposed to signifi- cant lateral loads. Lateral resistance of pile foundations typically is controlled by the stiffness and strength of the materials in the vicinity of the pile cap and surrounding the upper portion of the piles. When these materials are weak in comparison to the lateral loads that may be placed on the foundation, the foundation's design may be controlled by these lateral loads. A larger num- ber of piles or larger diameter piles and larger caps may be required and construction costs will be increased. Previous studies have shown that improving the strength of the weak materials may sig- nificantly increase pile lateral resistance. Improvements to be considered typically include removal and replacement of the in-situ materials, in-situ densification, grouting, or soil mix- ing using more granular materials or a binder such as Portland cement. Soil improvement extending a relatively limited distance around the piles and below the pile cap may be a cost- effective method for meeting foundation design requirements. Bridge foundation engineers have been hampered by a lack of verified design guidelines for estimating the increase in pile lateral resistance to be gained from soil improvement. The objective of NCHRP Project 24-30 was to develop such design guidelines. A team led by Brigham Young University first reviewed recent practice, test data, exist- ing specifications, and research findings from both foreign and domestic sources concern- ing the use of soil improvement techniques to increase the lateral resistance of piles. From this review, the research team developed a descriptive cataloging of soil improvement tech- niques to be addressed by the design guidelines. The catalog included likely applicability of each technique to specific weak soil types, such as soft cohesive soils, loose granular soils, or organic materials.
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The team then described analytical methods that may be used to estimate the increased lateral resistance achievable through soil improvement around single piles and pile groups. A set of prototypical foundation designs was developed for testing to calibrate and verify analysis estimates. These designs were then field tested in weak soils near Interstate 15 in Salt Lake City, Utah. This report describes the experimental design and field testing. The research team used finite-element methods and field-test results to perform a com- prehensive parametric analysis to quantify the effect of soil improvement on the lateral resistance of piles in bridge foundations. Through this analysis, the researchers developed design guidelines and found that simplified computational methods employing widely used, commercially available software generally will provide acceptably accurate results for highway-bridge design. The guidelines and analysis methods presented in this report may be useful to bridge foun- dation designers facing the problem of ensuring that foundations will perform acceptably under lateral loads produced by wave action, wind, seismic events, ship impact, or traffic.
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CONTENTS 1 Summary 3 Chapter 1 Introduction 5 Chapter 2 Available Ground Improvement Case Histories and Approaches 14 Chapter 3 Field Load Testing 14 3.1 Test Site Location 14 3.2 Geotechnical Site Characterization 15 3.3 Single Pile Test in Untreated Soil 23 3.4 Pile Group Properties 23 3.5 Pile Group Testing Procedure 25 3.6 Pile Group Tests in Untreated Clay 32 3.7 Pile Group Load Tests Involving Jet Grouting 36 3.8 Pile Group Load Tests Involving Soil Mixing 37 3.9 Pile Group Load Tests Involving Flowable Fill 39 3.10 Pile Group Load Tests Involving Excavation and Replacement 48 3.11 Summary of Increased Resistance from Soil Improvement Methods and Cost Considerations 51 Chapter 4 Finite Element Modeling of Single Pile Load Test 54 Chapter 5 Finite Element Modeling of Pile Group Load Tests 54 5.1 Pile Group FEM Mesh Design 56 5.2 FEM Model for Pile Group Model in Virgin Clay 56 5.3 Pile Group Model in Virgin Clay with Excavation 57 5.4 FEM Model of Pile Group with Mass Mixing 57 5.5 Pile Group Model with Jet Grouting 61 Chapter 6 Parametric Studies 61 6.1 Mass Mix Depth Effect (Beside the Cap) on Lateral Resistance 61 6.2 Mass Mix Depth Effect (Below the Cap) on Lateral Resistance 65 6.3 Mass Mix Length Effect (Beside the Cap) on Lateral Resistance 66 6.4 Jet Grout Depth Effect (Beside the Cap) on Lateral Resistance 68 6.5 Jet Grout Depth Effect (Below the Cap) on Soil Improvement 68 6.6 Jet Grout Length Effect (Beside the Cap) on Soil Improvement 71 6.7 Material Strength Effect on Lateral Pile Group Resistance 72 6.8 Conclusions Based on Parametric Studies 76 Chapter 7 Development of Simplified Model 76 7.1 Calibration GROUP Analysis Model 76 7.2 Comparison with Results from Tests in Virgin Soil 79 7.3 Comparison with Results from Tests Involving Mass Mixing 79 7.4 Development of Simplified Method
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85 7.5 Evaluation for Jet Grouting Cases 89 7.6 Design Recommendations 96 Chapter 8 Conclusions 97 References 99 Appendix A Schematic Drawings Showing the Layout of the 16 Lateral Pile Group Tests 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.