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Handbook of Scour Countermeasures Designs Handbook of Scour Countermeasures Designs

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Handbook of Scour Countermeasures Designs Handbook of Scour Countermeasures Designs FHWA-NJ-2005-027 Handbook of Scour Countermeasures Designs Handbook of Scour Countermeasures Designs FINAL REPORT December 2007 Submitted by Dr. Anil Kumar Agrawal Ph.D., P.E. Dr. Mohiuddin Ali Khan Ph.D., P.E. Professor, City College of the City Consultant University of New York Zhihua Yi, Graduate Student City College of the City University of New York Region 2 Transportation Research Center NJDOT Research Project Manager W. Lad Szalaj In cooperation with New Jersey Department of Transportation Division of Research and Technology and U.S. Department of Transportation Federal Highway Administration DISCLAIMER STATEMENT “The contents of this report reflect the views of the author(s), who is (are) responsible for the facts and the accuracy of the data presented herein. The contents do not necessarily reflect the official views or policies of the New Jersey Department of Transportation or the Federal Highway Administration. This report does not constitute a standard, specification, or regulation.” TECHNICAL REPORT STANDARD TITLE PAGE 1. Report No. 2.Government Accession No. 3. Recipient’s Catalog No. FHWA-NJ-2005-027 4. Title and Subtitle 5. Report Date December 2007 Handbook of Scour Countermeasures Designs 6. Performing Organization Code 7. Author(s) 8. Performing Organization Report No. A.K. Agrawal, M.A. Khan and Z. Yi 9. Performing Organization Name and Address 10. Work Unit No. University Transportation Research Center The City College of New York New York, NY 10031 11. Contract or Grant No. 49777-11-04 & 49777-11-05 12. Sponsoring Agency Name and Address 13. Type of Report and Period Covered Final Report New Jersey Department of Federal Highway Administration 1/1/03 – 6/30/05 Transportation U.S. Department of Transportation 14. Sponsoring Agency Code PO 600, Trenton, NJ 08625 Washington, D.C. 15. Supplementary Notes 16. Abstract Scour critical bridges throughout New Jersey are retrofitted using different standards for countermeasures, depending on the bridge ownership. This handbook has been prepared with a goal to provide a unified guideline for design of scour countermeasures for both new and old bridges in New Jersey to city, county and state engineers and bridge structural consultants. All important aspects specific to scour conditions in New Jersey have been identified through an in-depth review of NJDOT Phase II inspection reports of scour critical bridges. A detailed review of all available resources on scour countermeasure design, including HEC 11, 18, 20 and 23, CIRIA Manual (2002), NCHRP 24-07 report, scour countermeasure drawings by Maryland State Highway Administration and numerous research articles on scour countermeasure design, has been carried out to recommend effective countermeasures suitable to river conditions in New Jersey. Guidelines proposed for selected countermeasures are based on their effectiveness during past applications around the world, physical tests and the best design practice followed in the subject area. The handbook presents comprehensive guidelines on all aspects of various scour countermeasures, including constructability and environmental constraints specific to New Jersey. The design guidelines presented in this handbook supplement Hydraulic Engineering Circulars and have been developed with an aim to provide the engineers all important aspects of scour countermeasure design for New Jersey conditions in a collective and systematic manner. The engineers should refer to specific HEC in case of more detailed information on specific aspects of scour countermeasure design discussed in this manual. 17. Key Words 18. Distribution Statement Scour, Scour Protection, Scour Countermeasures NO RESTRICTION 19. Security Classif (of this report) 20. Security Classif. (of this page) 21. No of Pages 22. Price Unclassified Unclassified 215 NA Form DOT F 1700.7 (8-69) ACKNOWLEDGMENT This work has been sponsored by the New Jersey Department of Transportation and the Region 2 University Transportation Research Center. The authors are grateful to the assistance and patience of Dr. Nazhat Aboobaker, Mr. Jose Lopez, Mr. Jack Mansfield, Mr. Annam Achutha, Mr. Ayodele Oshilaja, Mr. W. Lad Szalaj and the Subject Matter Experts of the Scour Handbook Review Panel appointed by The New Jersey Department of Transportation. We would also like to thank Mr. Stan Davis of The Maryland State Highway Administration and Mr. Scott Thorn P.E., NJDOT, for providing scour countermeasure guidelines and drawings. ii TABLE OF CONTENTS CHAPTER 1: INTRODUCTION TO SCOUR OF BRIDGE FOUNDATIONS .............................................. 1 Background...............................................................................................................................................1 Scours at Abutments and Piers ................................................................................................................3 Site-Specific Data for Scour Analysis and Design....................................................................................4 Scour Studies in New Jersey....................................................................................................................4 Rivers in New Jersey................................................................................................................................4 Applications of Computer Software for Scour Analysis. ...........................................................................6 Organization of the handbook ..................................................................................................................6 CHAPTER 2: ENVIRONMENTAL ASPECTS OF COUNTERMEASURES INSTALLATION..................... 7 Introduction ...............................................................................................................................................7 Countermeasure Selection for Stream Beds and Banks..........................................................................8 Interference from Underground Utilities..................................................................................................11 CHAPTER 3: GEOTECHNICAL CONSIDERATIONS............................................................................... 12 Introduction .............................................................................................................................................12 Scour in Cohesive Soils..........................................................................................................................14 Soil Profiles for Typical Scour Critical Bridges in NJ ..............................................................................14 Soil Types Affecting Scour .....................................................................................................................15 Soil Types Affecting Scour Depth...........................................................................................................16 Countermeasures for Footings on Soil and Rock...................................................................................17 Debris Accumulation...............................................................................................................................18 Countermeasures for Debris Accumulation........................................................................................21 Formation of Scour Holes at Bridge Sites ..............................................................................................21 Unknown Foundations............................................................................................................................24 CHAPTER 4: APPLICATION OF MODERN TECHNIQUES TO CONTAIN EROSION............................ 26 Introduction .............................................................................................................................................26 Armoring Countermeasures ...................................................................................................................27 Countermeasures Alternative to Temporary Riprap...............................................................................29 Exceptions to Providing a Full-Scale Countermeasure ..........................................................................30 CHAPTER 5: COUNTERMEASURES FOR ABUTMENTS, PIERS, ARCHES & CULVERTS ................ 33 Footing Types and Scour at Abutments .................................................................................................33 Recommended Countermeasures for Abutments ..................................................................................33 Typical Pier Footings ..............................................................................................................................34 Scour at Piers .........................................................................................................................................39 Recommended Pier Scour Countermeasures........................................................................................42 Scour Protection at Arches & Culverts ...................................................................................................43 Hydraulic Design ................................................................................................................................43 Types of Arches..................................................................................................................................43 Types of Culverts................................................................................................................................45
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