Load transfer from a steel pile driven through compressible silt to rock. 24 Figure 23: Load transfer from tubular-steel piles in stiff clay. 24 Figure 24. Effect of
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TRANSPORTATION RESEARCH BOARD 1977 Officers ROBERT N. HUNTER, Chairman SCHEFFER LANG, Vice Chairman W. N. CAREY, JR., Executive Director Executive Committee HENRIK E. STAFSETH, Executive Director, American Assn. of State Highway and Transportation Officials (ex officio) WILLIAM M. COX, Federal Highway Administrator, U.S. Department of Transportation (ex officio) RICHARD S. PAGE, Urban Mass Transportation Administrator, U.S. Department of Transportation (ex officio) JOHN M. SULLIVAN, Federal Railroad Administrator, U.S. Department of Transportation (ex officio) HARVEY BROOKS, Chairman, Commission on Sociotechnical Systems, National Research Council (ex officio) MILTON PIKARSKY, Chairman of the Board, Chicago Regional Transportation Authority (ex officio, Past Chairman 1975) HAROLD L. MICHAEL, School of Civil Engineering, Purdue University (ex officio, Past Chairman 1976) WARREN E. ALBERTS, Vice President (Systems Operations Services), United Airlines GEORGE H. ANDREWS, Vice President (Transportation Marketing), Sverdrup and Parcel GRANT BASTIAN, State Highway Engineer, Nevada Department of Highways KURT W. BAUER, Executive Director, Southeastern Wisconsin Regional Planning Commission MANUEL CARBALLO, Lecturer in Public Management, Harvard University L. DEBERRY, Engineer-Director, Texas State Department of Highways and Public Transportation LOUIS J. GAMBACCINI, Vice President and General Manager, Port Authority Trans-Hudson Corporation HOWARD L. GAUTHIER, Professor of Geography, Ohio State University FRANK C. HERRINGER, General Manager, San Francisco Bay Area Rapid Transit District ARTHUR J. HOLLAND, Mayor, City of Trenton, NJ. ANN R. HULL, Speaker Pro Tem, Maryland House of Delegates ROBERT N. HUNTER, Chief Engineer, Missouri State Highway Department PETER G. KOLTNOW, President, Highway Users Federation for Safety and Mobility THOMAS J. LAMPHIER, President, Transportation Division, Burlington Northern, Inc. A. SCHEFFER LANG, Assistant to the President, Association of American Railroads DANIEL McFADDEN, Professor of Economics, University of California ROBERT S. MICHAEL, Director of Aviation, City and County of Denver, Colorado THOMAS D. MORELAND, Commissioner, Georgia Department of Transportation GEORGE E. PAKE, Vice President, Xerox Corp.; Manager, Xerox Palo Alto Research Center DOUGLAS N. SCHNEIDER, JR., Director, District of Columbia Department of Transportation WILLIAM K. SMITH, Vice President (Transportation), General Mills NATIONAL COOPERATIVE HIGHWAY RESEARCH PROGRAM Transportation Research Board Executive Committee Subcommittee for the NCHRP ROBERT N. HUNTER, Missouri State Highway Department (Chairman) A. SCHEFFER LANG, Association of American Railroads HENRIK E. STAFSETH, Amer. Assn. of State Hwy. and Transp. Officials WILLIAM M. COX, U.S. Department of Transportation HARVEY BROOKS, National Research Council HAROLD L. MICHAEL, Purdue University W. N. CAREY, JR., Transportation Research Board Topic Panel on Pile Foundations Project Committee SP 20-5 RAY R. BIEGE, JR., Kansas Dept. of Transportation (Chairman) VERDI ADAM, Louisiana Department of Highways JACK FREIDENRICH, New Jersey Department of Transportation DAVID GEDNEY, Federal Highway Administration EDWARD J. HEINEN, Minnesota Department of Highways BRYANT MATHER, USAE Waterways Experiment Station THOMAS H. MAY, Pennsylvania Department of Transportation THEODORE F. MORF, Consultant EDWARD A. MUELLER, Jack.vonville Transportation Authority REX C. LEATHERS, Federal Highway Administration ROY C. EDGERTON, Transportation Research Board Program Staff BERNARD E. BurLER, New York State Dept. of Transportation DAVID S. GEDNEY, Federal Highway Administration BERNARD A. GRAND, Slattery Associates DAVID HUVAL, Louisiana Department of Highways PHILIP KEENE, Consultant WENDEL T. RUFF, Mississippi State Highway Department J. W. GUINNEE, Transportation Research Board L. F. SPAINE, Transportation Research Board Consultant to Topic Panel ALEKSANDAR S. VESK, J. A. Jones Professor and Dean, School of Engineering, Duke University KRIEGER W. HENDERSON, JR., Program Director HARRY A. SMITH, Projects Engineer DAVID K. WITHEFORD, Assistant Program Director ROBERT E. SPICHER, Projects Engineer LOUIS M. MAcGREGOR, Administrative Engineer HERBERT P. ORLAND, Editor R. IAN KINGHAM, Projects Engineer PATRICIA A. PETERS, Associate Editor ROBERT J. REILLY, Projects Engineer EDYTHE T. CRUMP, Assistant Editor
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NATIONAL COOPERATIVE HIGHWAY RESEARCH PROGRAM SYNTHESIS OF HIGHWAY PRACTICE 42 DESIGN OF PILE FOUNDATIONS ALEKSANDAR S. VESI DUKE UNIVERSITY DURHAM, NORTH CAROLINA RESEARCH SPONSORED BY THE AMERICAN ASSOCIATION OF STATE HIGHWAY AND TRANSPORTATION OFFICIALS IN COOPERATION WITH THE FEDERAL HIGHWAY ADMINISTRATION AREAS OF INTEREST: BRIDGE DESIGN CONSTRUCTION FOUNDATIONS (SOILS) RAIL TRANSPORT TRANSPORTATION RESEARCH BOARD NATIONAL RESEARCH COUNCIL WASHINGTON, D.C. 1977
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NATIONAL COOPERATIVE HIGHWAY RESEARCH PROGRAM Systematic, well-designed research provides the most ef-fective 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 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 Trans-portation 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 sup-port of the Federal Highway Administration, United States Department of Transportation. The Transportation Research Board of the National Re-search Council was requested by the Association to admin-ister the research program because of the Board’s recog-nized 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 its parent organization, the National Academy of Sciences, a private, nonprofit institution, is an insurance of objectivity; it maintains a full-time research correlation staff of special-ists 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 trans-portation departments and by committees of AASHTO. Each year, specific areas of research needs to be included in the program are proposed to the Academy and the Board by the American Association of State Highway and Trans-portation Officials. Research projects to fulfill these needs are defined by the Board, and qualified research agencies are selected from those that have submitted proposals. Ad-ministration and surveillance of research contracts are responsibilities of the Academy and its Transportation Research Board. The needs for highway research are many, and the National Cooperative Highway Research Program can make signifi-cant 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 42 Project 20-5 FY ’73 (Topic 5-04) ISBN 0-309-02544-3 L. C. Catalog Card No. 77-90474 Price: $4.80 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, acting in behalf of the National Academy of Sciences. Such approval reflects the Governing Board’s judgment that the program concerned is of national impor-tance and appropriate with respect to both the purposes and re-sources of the National Research Council. The members of the technical committee selected to monitor this project and to review this report were chosen for recognized scholarly competence and with due consideration for the balance of disciplines appropriate to the project. The opinions and con-clusions expressed or implied are those of the research agency that performed the research, and, while they have been accepted as appropriate by the technical committee, they are not necessarily those of the Transportation Research Board, the National Research Coun-cil, the National Academy of Sciences, or the program sponsors. Each report is reviewed and processed according to procedures established and monitored by the Report Review Committee of the National Academy of Sciences. Distribution of the report is ap-proved by the President of the Academy upon satisfactory comple-tion of the review process. The National Research Council is the principal operating agency of the National Academy of Sciences and the National Academy of Engineering, serving government and other organizations. The Transportation Research Board evolved from the 54-year-old High-way Research Board. The TRB incorporates all former HRB activities but also performs additional functions under a broader scope involving all modes of transportation and the interactions of transportation with society. Published reports of the NATIONAL COOPERATIVE HIGHWAY RESEARCH PROGRAM are available from: Transportation Research Board National Academy of Sciences 2101 Constitution Avenue, N.W. Washington, D.C. 20418 Printed in the United States of America.
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PREFACE There exists a vast storehouse of information relating to nearly every subject of concern to highway administrators and engineers. Much of it resulted from research and much from successful application of the engineering ideas of men faced with problems in their day-to-day work. Because there has been a lack of systematic means for bringing such useful information together and making it available to the entire highway fraternity, the American Association of State Highway and Trans-portation Officials has, through the mechanism of the National Cooperative Highway Research Program, authorized the Transportation Research Board to undertake a continuing project to search out and synthesize the useful knowledge from all pos-sible sources and to prepare documented reports on current practices in the subject areas of concern. This synthesis series attempts to report on the various practices, making spe-cific recommendations where appropriate but without the detailed directions usually found in handbooks or design manuals. Nonetheless, these documents can serve similar purposes, for each is a compendium of the best knowledge available on those measures found to be the most successful in resolving specific problems. The extent to which they are utilized in this fashion will quite logically be tempered by the breadth of the user’s knowledge in the particular problem area. FOREWORD By Stafj Transportation Research Board This synthesis will be of special interest and usefulness to bridge engineers and others seeking information on pile foundations. Detailed information is presented on pile design principles and criteria. Administrators, engineers, and researchers are faced continually with many highway problems on which much information already exists either in documented form or in terms of undocumented experience and practice. Unfortunately, this information often is fragmented, scattered, and unevaluated. As a consequence, full information on what has been learned about a problem frequently is not assembled in seeking a solution. Costly research findings may go unused, valuable experience may be overlooked, and due consideration may not be given to recom-mended practices for solving or.alleviating the problem. In an effort to correct this situation, a continuing NCHRP project, carried out by the Transportation Research Board as the research agency, has the objective of synthesizing and reporting on common highway problems. Syntheses from this endeavor constitute an NCHRP report series that collects and assembles the various forms of information into single
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concise documents pertaining to specific highway problems or sets of closely related problems. Pile foundations are used by all state highway agencies and by other organiza-tions involved in civil engineering projects. However, present procedures for design vary considerably among agencies and in some cases do not reflect the best available information. This report of the Transportation Research Board reviews design principles and construction problems and recommends criteria based on current knowledge. To develop this synthesis in a comprehensive manner and to ensure inclusion of significant knowledge, the Board analyzed available information assembled from numerous sources, including a large number of state highway and transportation departments. A topic panel of experts in the subject area was established to guide the researchers in organizing and evaluating the collected data, and to review the final synthesis report. This synthesis is an immediately useful document that records practices that were acceptable within the limitations of the knowledge available at the time of its preparation. As the processes of advancement continue, new knowledge can be expected to be added to that now at hand.
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FIGURES 4 Figure 1. Situations in which piles may be needed. 8 Figure 2. Failure pattern under a model pile in soft dày. 9 Figure 3. Load-displacement diagrams for series of test piles in sand. 11 Figure 4. Load-displacement diagram of a test pile drawn in two different scales. 11 Figure 5. Basic problem of a deep foundation. 11 Figure 6. Effects of placement of pile into a soil mass. 13 Figure 7. Assumed failure pattern under pile point. 13 Figure 8. Failure patterns under pile point in dense sand. 14 Figure 9. The shape of wedge, variations of sand density, and displacement pattern under the tip of a 20-cm pile in dense sand. 14 Figure 10. Variation of bearing capacity factor N. with L and 0. 15 Figure 11. Experimental values of Nq* in sand from different investigations. 16 Figure 12. Comparison between skin resistance of piles in clay and undrained strength. 17 Figure 13. Field data on increase of bearing capacity with time for friction piles in clay. 18 Figure 14. Observed values of skin bearing capacity factor N. in normally consolidated clays. 19 Figure 15. Observed values of N. for bored piles in London clay. 20 Figure 16. Observed values of N. for driven piles in stiff, overconsolidated clays. 20 Figure 17. Variation of skin resistance of piles in sand with relative density. 21 Figure 18. Evaluation of point resistance of 18-in. (450-mm)-diameter pile from results of static-penetra- tion test. 22 Figure 19. Transfer factor X=q0/P0 for cohesionlèss soils. 23 Figure 20. Mobilization of base and shaft resistance as a function of pile displacement. 23 Figure 21. Relative magnitude of point loads at various stages of loading of closed-end pipe piles in dense sand. 23 Figure 22. Load transfer from a steel pile driven through compressible silt to rock. 24 Figure 23: Load transfer from tubular-steel piles in stiff clay. 24 Figure 24. Effect of residual loads on load distribution in driven piles in sand at Arkansas River. 25 Figure 25. Measured distributions of skin resistance. 26 Figure 26. Axial load developed by negative skin friction in. open-end and closed-end pipes in silt, ending in dense sand. 27 Figure 27. Load transfer from a single pile. 27 Figure 28. Typical simple distributions of skin resistance. 28 Figure 29. Load-transfer analysis: (a) elastic-solid approach and (b) transfer-function approach. 29 Figure 30. Distribution of vertical stresses around a pile in elastic solid. 30 Figure 31. Finite-element analysis of load transfer. 30 Figure 32. Deformation models used in load-transfer analysis. 31, Figure 33. Computed distribution of skin friction for Arkansas River site piles loaded in cyclic com- pression. 34 Figure 34. Typical configurations of pile groups. 34 Figure 35. Observed efficiencies of square pile groups in sand. 35 Figure 36. Effect of driving sequence on efficiency of piles in loose sand. 36 Figure 37. Single pile under the action of lateral loads. 38 Figure 38. Variation of coefficient of subgrade reaction (its) for piles in sand. 38 Figure 39. Variation of coefficient of subgrade reaction (nh) for piles in clay. 39 Figure 40. Increase of deflection of laterally loaded piles under cyclic loading. 39 Figure 41. Piles subjected to lateral movement of soil. 40 Figure 42. Basic problem of a pile subjected to lateral soil movement. 40 Figure 43. Buckling of partially embedded piles. 41 Figure 44. Examples of structural systems with batter piles. 41 Figure 45. Problem of a pile foundation subjected to eccentric and inclined loads. 42 Figure 46. Definition of pile coefficients. 43, Figure 47. Sign convention for p and q. 43 Figure 48. Group of vertical piles subjected to eccentric and inclined loads. 44 Figure 49. Principle of operation of pile drivers. 47 Figure 50. Problem of pile driving. 48 Figure 51. Rheological model of soil resistance at pile-soil interface. 48 Figure 52. Relationship between peak driving force and pile impedance for Vulcan SA hammers. Shaded area indicates conditions of maximum transmission of driving energy. 49 Figure 53. Discrete-element model of the pile-soil system. 50 Figure 54. Typical result of wave-equation analysis of driving stresses. 50 Figure 55. Typical result of wave-equation analysis of pile resistance. 51 Figure 56. Typical setup for pile load testing in axial compression using anchor piles. 52 Figure 57. Typical setup for pile load testing in axial compression using a loading platform. 53 Figure 58. Typical setup for measurement of pile displacements. 54 Figure 59. Typical setup for pile load testing in tension using direct jacking with straps. 54 Figure 60. Typical setup for pile load testing in tension using cross-beams. 55 Figure 61. Typical setup for lateral load tests.
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TABLES 5 Table 1. Principal Advantages and Disadvantages of Different Pile Types. 10 Table 2. Rules for Determination of Ultimate Load. 16 Table 3. Experimental Values of Nq* in Sand. 28 Table 4. Methods of Load Transfer Analysis by Transfer Function Approach. 29 Table 5. Method of Load Transfer Analysis by Elastic Solid Approach. 33 Table 6. Typical Values of Coefficients C. 45 Table 7. Impact Pile-Driver Data. 46 Table 8. Comparison of Vibratory Drivers. 46 Table 9. Typical Pile Cushion Material Properties. 48 Table 10. Stress-Transmission Characteristics of Typical Piles. 66 Table A-i. Bearing Capacity Factors for Deep Foundations. 68 Table A-2. Typical Values of Rigidity Index, Ir.
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ACKNOWLEDGMENTS This synthesis was completed by the Transportation Research Board under the supervision of Paul E. Irick, Assistant Direc-tor for Special Projects. The Principal Investigators respon-sible for conduct of the synthesis were Thomas L. Copas and Herbert A. Pennock, Special Projects Engineers. This syn-thesis was edited by Deborah K. Farmer. Special appreciation is expressed to Dr. Aleksandar S. Vesi6, J. A. Jones Professor and Dean, School of Engineering, Duke University, who was responsible for the collection of data and preparation of the report. Valuable assistance in the preparation of this synthesis was provided by the Topic Panel, consisting of Bernard E. Butler, Associate Soils Engineer, New York State Department of Transportation; David S. Gedney, Director, Northeast Corridor Assistance Project, Federal Highway Administration; Bernard A. Grand, Chief Design Engineer, Slattery Associates, Maspeth, N. Y., David Huval, Bridge Design Engineer, Louisiana De-partment of Highways; Philip Keene, Consultant, Middletown, Conn.; Wendel T. Ruff, Chief Soils Engineer, Mississippi State Highway Department. John W. Guinnee, Engineer of Soils, and Lawrence F. Spaine, Engineer of Design, Transportation Research Board, assisted the Special Projects staff and the Topic Panel.
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DESIGN OF PILE FOUNDATIONS SUMMARY The first problem facing the designer of a foundation is to determine whether or not the site conditions are such that piles must be used. Piles are used where upper soil strata are compressible or weak; where footings cannot transmit inclined, horizontal, or uplift forces; where scour is likely to occur; where future excavation may be adjacent to the structure; and where expansive or collapsible soils extend for a considerable depth. Piles may be classified by material type or by method of placement. The choice of pile type is influenced by subsurface conditions, location and topography of the site, and structural and geometric characteristics of the structure to be supported. The designer of a deep foundation must possess a variety of skills, much experi-ence, and considerable knowledge of engineering sciences. No set of simple rules and procedures can be expected to cover the variety of conditions and forms of instability that can endanger a deep foundation. The ultimate load on a pile is the load that can cause failure of either the pile or the soil. The pile failure condition may govern design where pile points pene-trate dense sand or rock, but in most situations, ultimate load is determined by the soil failure. The soil always fails in the same manner: punching shear under the point, accompanied or preceded by direct-shear failure along the shaft. Because the ultimate load is often not well defined, various empirical ultimate load criteria have to be used. Most often these have been based on considerations of plastic (irrecoverable) or total (plastic and elastic) settlements of the pile under a test load. Unless the load-settlement curve shows a definite peak load, the most accept-able criterion would define the ultimate load as that causing total pile settlement equal to 10 percent of the point diameter for driven piles and 25 percent for bored piles. Computation of the ultimate load is quite difficult and a “general solution” is not yet available. For design purposes, the ultimate load is separated into two components: the base or point load, and the shaft or skin load. Theories for deter-mination of point load based on the plasticity theory are now considered inadequate and are being replaced by linear or nonlinear elasto-plastic theories. The theoretical approach for evaluation of skin resistance is similar to that used to analyze resistance to sliding of a rigid body in contact with the soil. Equations are available to calcu-late the point and skin resistances. However, the calculations require detailed knowledge of strength and deformation characteristics of the soil strata and also of the variation of density and water content within those strata. For most structures, the cost of obtaining this information is prohibitive; in addition, it is normally preferable to estimate unit resistance directly from such field tests as the static-cone-penetration test, standard penetration test, or pressuremeter test. The displacement needed to mobilize skin resistance is small compared to that for point resistance. Thus, ultimate skin resistance is reached much sooner than point resistance and the portion of the load carried by the point is smaller in work-ing conditions than at failure. In situations where soil around a pile moves downward (e.g., because of water removal from aquifer strata), it exerts a negative friction (downdrag) on the pile
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