Technical Report Documentation Page

1 Technical Report Documentation Page 1. Report No. FHWA-SA-02-054 2. Government Accession No. 3. Recipient s Catalog No. 5. Report Date September 2002 4. Title and Subtitle GEOTECHNICAL ENGINEERING CIRCULAR NO. 6 Shallow Foundations 6. Performing Organization Code 7. Author(s) Robert E. Kimmerling 8. Performing Organization Report No. 10. Work Unit No. (TRAIS) 9. Performing Organization Name and Address PanGEO, Inc. 3414 55th Street Seattle, Washington 98105 11. Contract or Grant No. DTFH61-00-C-00031 13. Type of Report and Period Covered Technical Manual 12. Sponsoring Agency Name and Address Office of Bridge Technology Federal Highway Administration HIBT, Room 3203 400 Seventh Street, Washington, 20590 14. Sponsoring Agency Code 15.

2 Supplementary Notes Contracting Officer s Technical Representative: Chien-Tan Chang (HIBT) FHWA Technical Consultant: Jerry DiMaggio (HIBT) 16. Abstract This document is FHWA s primary reference of recommended design and procurement procedures for shallow foundations. The Circular presents state-of-the-practice guidance on the design of shallow foundation support of highway bridges. The information is intended to be practical in nature, and to especially encourage the cost-effective use of shallow foundations bearing on structural fills. To the greatest extent possible, the document coalesces the research, development and application of shallow foundation support for transportation structures over the last several decades.

3 Detailed design examples are provided for shallow foundations in several bridge support applications according to both Service Load Design (Appendix B) and Load and Resistance Factor Design (Appendix C) methodologies. Guidance is also provided for shallow foundation applications for minor structures and buildings associated with transportation projects. 17. Key Words Shallow foundation, spread footing, abutment, mat foundation, bearing capacity, settlement, eccentricity, overturning, sliding, global stability, LRFD 18. Distribution Statement No Restrictions. This document is available to the public from the National Technical Information Service, Springfield, Virginia 22161 19. Security Classification (of this Report ) 20.

4 Security Classification (of this page) 21. No. of pages 310 22. Price Form DOT F (8-72) Reproduction of completed page authorized NOTICE The information in this document has been funded wholly or in part by the Department of Transportation, Federal Highway Administration (FHWA), under Contract No. DTFH61-00-C-00031 to PanGEO, Inc. The document has been subjected to peer and administrative review by FHWA and has been approved for publication as a FHWA document. The contents of this Report reflect the views of the author, who is responsible for the facts and accuracy of the data presented herein. The contents do not necessarily reflect the policy of the Department of Transportation. This Report does not constitute a standard, specification or regulation.

5 The United States Government does not endorse products or manufacturers. Mention of trade names or commercial products does not constitute endorsement or recommendation for use by either the author or FHWA. GEOTECHNICAL ENGINEERING CIRCULAR NO. 6 SHALLOW FOUNDATIONS PREFACE This document is the sixth in a series of Geotechnical Engineering Circulars (GEC) developed by the Federal Highway Administration (FHWA). This Circular focuses on the design, procurement and construction of shallow foundations for highway structures. The intended users are practicing geotechnical, foundation and structural engineers involved with the design and construction of transportation facilities. Other circulars in this series include the following: - GEC No.

6 1 Dynamic Compaction (FHWA-SA-95-037) - GEC No. 2 Earth Retaining Systems (FHWA-SA-96-038) - GEC No. 3 Design Guidance: Geotechnical Earthquake Engineering for Highways, Volume I Design Principles (FHWA-SA-97-076) Volume II Design Examples (FHWA-SA-97-077) - GEC No. 4 Ground Anchors and Anchored Systems (FHWA-SA-99-015) - GEC No. 5 Evaluation of Soil and Rock Properties (FHWA-IF-02-034) - GEC No. 7 Soil Nailing (under development) This Circular is intended to be a stand-alone document geared toward providing the practicing engineer with a thorough understanding of the analysis and design procedures for shallow foundations on soil and rock, with particular emphasis on bridges supported on spread footings. Accordingly, the manual is organized as follows: Chapters 1 and 2 present background information regarding the applications of shallow foundations for transportation structures.

7 Chapters 3 and 4 present methods used to perform foundation type selection, including the minimum level of subsurface investigation and laboratory testing needed to support design of shallow foundations. Chapter 5 presents the soil mechanics theory and methods that form the basis of shallow foundation design. Chapter 6 describes the shallow foundation design process for bridge foundation support on spread footings. Chapters 5 and 6, together with the detailed bridge foundation design examples presented in Appendix B, provide the practical information necessary to complete shallow foundation design for a highway bridge. i Chapters 7 and 8 discuss the application and special spread footing design considerations for minor transportation structures and buildings.

8 Chapters 9 and 10 provide guidelines for procurement and construction monitoring of shallow foundations. Appendix A provides recommended materials specifications for embankments constructed to support shallow foundations. The appendix also includes example material specifications used by state highway agencies that design and construct spread footings in compacted structural embankments. Appendix B includes five worked design examples of shallow foundations for highway bridges based on Service Load Design methodology. Appendix C includes practical guidance on the use of Load and Resistance Factor Design (LRFD) methodology for shallow foundation design and reworks two of the design examples from Appendix B using LRFD.

9 This Circular was developed for use as a desktop reference that presents FHWA recommended practice on the design and construction of shallow foundations for transportation structures. To the maximum extent possible, this document incorporates the latest research in the subject matter area of shallow foundations and their transportation applications. Attention was given throughout the document to ensure the compatibility of its content with that of reference materials prepared for the other FHWA publications and training modules. Special efforts were made to ensure that the included material is practical in nature and represents the latest developments in the field. ii ACKNOWLEDGMENTS Special thanks are given to the state highway agency personnel who contributed to the collection of data regarding the state of the practice in using shallow foundations for support of highway bridges.

10 The Nevada, Michigan and Washington State Departments of Transportation are especially acknowledged for providing the case history data included in this Circular. Notable and much appreciated contributions to the design examples included in this Circular were provided by Messrs. George Machan, Will Shallenberger and Kenji Yamasaki of Cornforth Consultants, Inc., Portland, Oregon, and by Ms. Tiffany Adams and Mr. Siew Tan of PanGEO, Inc., Seattle, Washington. Particular gratitude is extended to Mr. Ronald G. Chassie, formerly with FHWA, Mr. Monte J. Smith of Sargent Engineers, Inc., Olympia, Washington, and Mr. James L. Withiam of D Appolonia, Monroeville, Pennsylvania for their extremely helpful Technical review, input and commentary provided on the document.