Guidance for Underwater Installation of Filter Systems (2018)

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2018 N A T I O N A L C O O P E R A T I V E H I G H W A Y R E S E A R C H P R O G R A M NCHRP RESEARCH REPORT 887 Guidance for Underwater Installation of Filter Systems P. E. Clopper P. F. Lagasse Ayres AssociAtes, inc. Fort Collins, CO Subscriber Categories Bridges and Other Structures • Hydraulics and Hydrology 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 research is the most effective way to solve 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 accelerating growth of highway transportation results in increasingly complex problems of wide inter- est 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 ini- tiated 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, United States Department of Transportation. 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 com- mittee 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, univer- sities, and industry; TRB’s relationship to the National Academies is an insurance of objectivity; and TRB maintains a full-time staff of special- ists 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 Federal Highway Administration. 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 Direc- tors and the National Academies. Research projects to address these top- ics 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. Published research 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 by going to http://www.national-academies.org and then searching for TRB Printed in the United States of America NCHRP RESEARCH REPORT 887 Project 24-42 ISSN 2572-3766 (Print) ISSN 2572-3774 (Online) ISBN 978-0-309-47983-7 Library of Congress Control Number 2018956756 © 2018 National Academy of Sciences. All rights reserved. COPYRIGHT INFORMATION Authors herein are responsible for the authenticity of their materials and for obtaining written permissions from publishers or persons who own the copyright to any previously published or copyrighted material used herein. 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, FAA, FHWA, FMCSA, FRA, FTA, Office of the Assistant Secretary for Research and Technology, PHMSA, or TDC 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; or the program sponsors. The Transportation Research Board; the National Academies of Sciences, Engineering, and Medicine; and the sponsors of the National Cooperative Highway Research Program do not endorse products or manufacturers. Trade or manufacturers’ names appear herein solely because they are considered essential to the object of the report.

The National Academy of Sciences was established in 1863 by an Act of Congress, signed by President Lincoln, as a private, non- governmental institution to advise the nation on issues related to science and technology. Members are elected by their peers for outstanding contributions to research. Dr. Marcia McNutt is president. The National Academy of Engineering was established in 1964 under the charter of the National Academy of Sciences to bring the practices of engineering to advising the nation. Members are elected by their peers for extraordinary contributions to engineering. Dr. C. D. Mote, Jr., is president. The National Academy of Medicine (formerly the Institute of Medicine) was established in 1970 under the charter of the National Academy of Sciences to advise the nation on medical and health issues. Members are elected by their peers for distinguished contributions to medicine and health. Dr. Victor J. Dzau is president. The three Academies work together as the National Academies of Sciences, Engineering, and Medicine to provide independent, objective analysis and advice to the nation and conduct other activities to solve complex problems and inform public policy decisions. The National Academies also encourage education and research, recognize outstanding contributions to knowledge, and increase public understanding in matters of science, engineering, and medicine. Learn more about the National Academies of Sciences, Engineering, and Medicine at www.national-academies.org. The Transportation Research Board is one of seven major programs of the National Academies of Sciences, Engineering, and Medicine. The mission of the Transportation Research Board is to increase the benefits that transportation contributes to society by providing 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 committees, task forces, and panels 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 individuals interested in the development of transportation. Learn more about the Transportation Research Board at www.TRB.org.

C O O P E R A T I V E R E S E A R C H P R O G R A M S AUTHOR ACKNOWLEDGMENTS The research supporting this document was performed under NCHRP Project 24-42 by Ayres Associates, Fort Collins, Colorado. Mr. Paul E. Clopper, Director of Applied Technology, Ayres Associates, served as Principal Investigator (PI). Dr. Peter F. Lagasse, Senior Water Resources Engineer, Ayres Associates, served as Co-PI. The laboratory testing performed under this project was conducted at the Colorado State University (CSU) Engineering Research Center. The authors wish to acknowledge the efforts of Dr. Robert Ettema, Research Associate, and Mr. Jason Berg, who supervised the CSU graduate students in hydraulic engineer- ing. Mr. Dylan Armstrong and Mr. Scott Nesbitt of Ayres Associates participated in the implementation of the laboratory testing phase and compiled the results of the laboratory study for the Research Team. A special acknowledgment is due to the highly qualified, certified divers who helped establish the lim- its and validated the requirements for underwater installation of filter systems. They included Mr. Jim Johnson of the High Plains Scuba Center in Fort Collins, Colorado; Mr. Gary Schranz; and Mr. Justin Fox. The assistance of Mr. Lotwick Reese, Senior Hydraulic Engineer, Idaho Department of Transportation, in providing data, design drawings, and a PowerPoint presentation to support the Snake River geotextile filter installation case study is gratefully acknowledged. Likewise, Mr. Dave Henderson, Senior Scour Engi- neer, FHWA Office of Bridges and Structures, Washington, D.C., provided valuable assistance in develop- ing the case study of operations at the Bonner Bridge in North Carolina (2013–2014), which is based on his article in FHWA’s Hydrologic and Hydraulic News (Volume 2, Issue 1, April 2014). Finally, the participation, advice, support, and suggestions of NCHRP panel members throughout this project are gratefully acknowledged. CRP STAFF FOR NCHRP RESEARCH REPORT 887 Christopher J. Hedges, Director, Cooperative Research Programs Lori L. Sundstrom, Deputy Director, Cooperative Research Programs Waseem Dekelbab, Senior Program Officer Megan A. Chamberlain, Senior Program Assistant Eileen P. Delaney, Director of Publications Natalie Barnes, Associate Director of Publications Ellen M. Chafee, Senior Editor NCHRP PROJECT 24-42 PANEL Field of Soils and Geology—Area of Mechanics and Foundations Steve Ng, Sacramento, CA (Chair) Barry R. Christopher, Christopher Consultants, Inc., Roswell, GA Nicolas P. Jadamec, Phoenix Marine Construction Co., Sayreville, NJ Blake E. Nelson, Minnesota DOT, Maplewood, MN Carlton D. Spirio, Jr., Florida DOT, Tallahassee, FL L. David Suits, North American Geosynthetics Society, Albany, NY Larry J. Tolfa, New York State DOT, Albany, NY Bart Bergendahl, FHWA Liaison

NCHRP Research Report 887 provides recommended design procedures, material testing requirements, installation alternatives, and quality checklist items for both granular and geotextile filters. The guidance includes a synthesis of the state of practice, internationally, for installing filter systems underwater. The report will be of immediate interest to hydraulic and bridge engineers. The ongoing occurrence of stream channel migration and scour are often cited as the leading cause of bridge and other failures in the United States. The growing need for tech- niques to control stream instability and scour has spawned considerable research on the benefits of various types of hydraulic countermeasures and a number of publications have been written, including FHWA’s Hydraulic Engineering Circular No. 23: Bridge Scour and Stream Instability Counter measures: Experience, Selection, and Design Guidance, which pro- vide guidance on the applicability and design of different countermeasure types. A com- ponent found to be necessary in many counter measure designs is the provision of a filter between the countermeasure and the underlying soil. While the countermeasure protects the soil from the shear stresses that erode the soil particles, a filter is needed to prevent the removal of soil particles through voids and gaps in the countermeasure structure. Installa- tions that do not include a filter can moderate the scour process but, ultimately, the removal of supporting soil particles results in an undermining and failure of the countermeasure. Geotextiles have become the filter of choice for most designers but traditional granular filters are also used. The current technical guidance on countermeasure design includes recommendations for either a geotextile or a granular filter to be placed under the counter- measure. However, there is little guidance for construction personnel on actual installa- tion techniques for installing a filter underwater. Through interviews conducted in FHWA hydraulic program reviews of state departments of transportation (DOTs) and from tech- nical assistance calls from bridge owners, it has become apparent that few countermeasure installations in water actually include a filter even though a filter is shown on the design plans and is recommended in the technical guidance. The most common reasons given for this omission of a filter are constructability issues or environmental concerns. DOT construc- tion and maintenance personnel, along with general contractors who perform the counter- measure installations, need guidance on how countermeasures function and the value of an underlying filter. Without this knowledge of the function of a properly installed filter, personnel have often eliminated underwater filters instead of developing creative techniques for filter installa- tion. Similarly, designers may not recognize the importance of addressing constructability and environmental concerns when selecting a filter system. Since an appropriate filter is an F O R E W O R D By Waseem Dekelbab Staff Officer Transportation Research Board

essential component of countermeasure armoring systems, this practice must be changed immediately if these systems are to function as designed. As such, research on filter selection, design, and installation techniques for scour and erosion countermeasure systems in various underwater conditions was warranted. Under NCHRP Project 24-42, Ayres Associates was asked to develop guidance for under- water installation of filter systems that considers various depths and velocities of stream flow for placing geotextiles and granular filters beneath countermeasures. In addition to the guidance published as NCHRP Research Report 887, the research agency’s final report, documenting the entire research effort, is available on the TRB website (www.trb.org) as NCHRP Web-Only Document 254: Underwater Installation of Filter Sys- tems for Scour and Erosion Countermeasures, Volume 1. In addition, a training manual for an under water filter installation workshop is available as NCHRP Web-Only Document 254, Volume 2. The training manual is supplemented with video clips and additional training materials in PowerPoint format.

1 Chapter 1 Introduction and Results 1 1.1 Background 2 1.2 Approach 2 1.3 Results 4 Chapter 2 Findings 4 2.1 Survey on Current State of Practice 4 2.1.1 General Information 5 2.1.2 Design-Related Issues 5 2.1.3 Underwater Installation Issues 7 2.1.4 Summary of Survey Results 7 2.2 Synthesis of Current State of Practice 7 2.2.1 Overview 7 2.2.2 Background and Approach 8 2.2.3 Purpose, Need, Function, and Design of the Filter Component of Countermeasure Armoring Systems 19 2.2.4 Documentation from European Practice for Filter Design 22 2.2.5 Traditional European Techniques for Installing Filter Systems Underwater 28 2.2.6 Current European Technology and Applications for Installing Filter Systems Underwater 37 2.2.7 U.S. Practice for Installation of Filter Systems Underwater 56 2.2.8 Special Applications 61 2.2.9 Permitting of Filter Installations 61 2.2.10 Additional Observations on the Installation of Geotextile Containers 66 Chapter 3 Documentation of Underwater Filter Installation Techniques 66 3.1 Overview 67 3.2 Diver-Assisted Filter Placement 67 3.2.1 Testing Facility 67 3.2.2 Testing Approach and Documentation 68 3.3 Underwater Installation of Granular Filters 68 3.3.1 Critical Velocity vs. Particle Size 69 3.3.2 Granular Filter Placement with a Flexible Tremie 71 3.4 Underwater Installation of Geotextile Filters 73 3.5 Appraisal of Underwater Installation Testing Results C O N T E N T S

75 Chapter 4 Guidance for Installation of Filter Systems 75 4.1 Overview 75 4.2 General Considerations 75 4.3 Selection Criteria for Underwater Filter Installation 76 4.3.1 Construction Constraints: Filter Selection Based on Site Access and Overhead Clearance 76 4.3.2 Placement Environment: Filter Selection Based on Velocity and Depth 79 4.3.3 Additional Considerations 79 4.4 Guidance for Underwater Installation of Granular Filters 79 4.4.1 Design 79 4.4.2 Installation 80 4.4.3 Inspection and Maintenance 80 4.4.4 Testing 80 4.4.5 Specifications 83 4.4.6 Quality Assurance/Quality Control 83 4.4.7 Environmental and Permitting Considerations 84 4.5 Guidance for Underwater Installation of Geotextile Filters 84 4.5.1 Design 84 4.5.2 Installation 85 4.5.3 Inspection and Maintenance 85 4.5.4 Testing 85 4.5.5 Specifications 86 4.5.6 Quality Assurance/Quality Control 87 4.5.7 Environmental and Permitting Considerations 88 4.6 Applications 88 4.6.1 Underwater Installation of a Filter for Scour Protection at a Riverine Bridge 93 4.6.2 Underwater Installation of a Filter for Scour Protection at a Coastal Bridge 98 4.7 Description of Stand-Alone Training Document 99 4.7.1 Part I 99 4.7.2 Part II 100 References 104 Acronyms, Abbreviations, and Initialisms Note: Photographs, figures, and tables in this report may 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.