Roadside Barrier Designs near Bridge Rail Ends with Restricted Rights-of-Way: A Guide (2022)

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2022 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 1013 Roadside Barrier Designs near Bridge Rail Ends with Restricted Rights-of-Way A GUIDE Richard Powers Karen Boodlal John Durkos Leverson Boodlal KLS Engineering, LLC Ashburn, VA a n d Dhafer Marzougui Cing Dao (Steve) Kan Kenneth Opiela Fadi Tahan Center for Collision Safety and Analysis The George Mason University Fairfax, VA Subscriber Categories Bridges and Other Structures • Design Research sponsored by the American Association of State Highway and Transportation Ofcials in cooperation with the Federal Highway Administration

NATIONAL COOPERATIVE HIGHWAY RESEARCH PROGRAM Systematic, well-designed, and implementable research is the most effective way to solve many problems facing state departments of transportation (DOTs) administrators and engineers. Often, highway problems are of local or regional interest and can best be studied by state DOTs individually or in cooperation with their state universities and others. However, the accelerating growth of highway transporta- tion results in increasingly complex problems of wide interest to high- way 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 (FHWA), United States Department of Transportation, under Agree- ment No. 693JJ31950003. 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 iden- tified by chief administrators and other staff of the highway and transportation departments, by committees of AASHTO, and by the FHWA. 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. 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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 https://www.mytrb.org/MyTRB/Store/default.aspx Printed in the United States of America NCHRP RESEARCH REPORT 1013 Project 15-53 ISSN 2572-3766 (Print) ISSN 2572-3774 (Online) ISBN 978-0-309-68750-8 Library of Congress Control Number 2022947631 © 2022 by the National Academy of Sciences. National Academies of Sciences, Engineering, and Medicine and the graphical logo are trade- marks of the 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, APTA, FAA, FHWA, FTA, GHSA, or NHTSA 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; the FHWA; or the program sponsors. The Transportation Research Board does not develop, issue, or publish standards or speci- fications. The Transportation Research Board manages applied research projects which provide the scientific foundation that may be used by Transportation Research Board sponsors, industry associations, or other organizations as the basis for revised practices, procedures, or specifications. 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. 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e 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. e 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. John L. Anderson is president. e 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. e 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. e 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.nationalacademies.org. e Transportation Research Board is one of seven major programs of the National Academies of Sciences, Engineering, and Medicine. e mission of the Transportation Research Board is to provide leadership in transportation improvements and innovation through trusted, timely, impartial, and evidence-based information exchange, research, and advice regarding all modes of transportation. e Board’s varied activities annually engage about 8,000 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. e 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 KLS Engineering and George Mason University project team acknowledges the NCHRP Proj- ect 15-53 panel for demonstrating confidence in the team’s capabilities and providing regular feedback during this project. Special thanks to the FHWA Office of Safety R&D for the support of this research by scheduling testing at the Federal Outdoor Impact Lab and Mr. Eduardo Arispe, who handled all the details to make it possible. This testing was critical to verify the effectiveness of the short-radius guardrail design developed under this project. The team thanks Gregory Industries for supplying the test article materials for the crash tests conducted under this project. It is also necessary to thank the many individuals from state departments of transportation, industry, and academia who provided insights, information, and data that were used in this research. CRP STAFF FOR NCHRP RESEARCH REPORT 1013 Christopher J. Hedges, Director, Cooperative Research Programs Waseem Dekelbab, Deputy Director, Cooperative Research Programs, and Manager, National Cooperative Highway Research Program Sid Mohan, Associate Program Manager, Implementation and Technology Transfer, National Cooperative Highway Research Program Christopher T. McKenney, Senior Program Officer Robert Turner II, Senior Program Assistant Natalie Barnes, Director of Publications Heather DiAngelis, Associate Director of Publications Lisa Whittington, Editor NCHRP PROJECT 15-53 PANEL Field of Design—Area of General Design Matthew W. Chandler, Tennessee Department of Transportation, Nashville, TN (Chair) Alexander K. Bardow, Massachusetts Department of Transportation, Boston, MA Ed Barry, Washington State Department of Transportation, Seattle, WA Mark Randall Burkhead, Harrisburg, PA Don Jay Gripne, DJG NW INC, Olympia, WA Mubeen S. Quadri, Ohio Department of Transportation, Columbus, OH William B. Wilson, Wyoming Department of Transportation, Cheyenne, WY Eduardo Arispe, FHWA Liaison Kelly K. Hardy, AASHTO Liaison Stephen F. Maher, TRB Liaison

NCHRP Research Report 1013 presents a guide on the application and installation of short-radius guardrail systems for roadside barriers near bridge rail ends with restricted rights-of-way. Development of the conceptual design for the short-radius barrier was based on computer simulation analyses and full-scale crash testing to meet AASHTO’s Manual for Assessing Safety Hardware (MASH) crashworthiness requirements and advance the state of the practice for roadside safety hardware development. This report will be of immediate interest to design and maintenance engineers. At many existing highway bridge locations throughout the United States, the length of need (LON) for guardrail required at bridge ends cannot be installed due to conflicts within the existing rights-of-way limits. The conflicts may consist of an existing intersecting pri- vate driveway, state or local roadway intersection, or other objects that do not allow the placement of the required guardrail LON for a road safety barrier installation to shield a roadside hazard. It is not unusual at some existing bridge sites to have 10 feet or less between the end of the bridge and the conflict. Because most Test Level 3 (TL-3) tangent or flared guardrail end treatment systems are normally within the range of 37 to 50 feet in length, there is typically a problem with fitting the end treatment systems and guardrail transi- tions to the bridge rail at these restricted sites. Additionally, no pre-existing short-radius guardrail system had been able to meet NCHRP Report 350: Recommended Procedures for the Safety Performance Evaluation of Highway Features or AASHTO’s Manual for Assessing Safety Hardware (MASH) TL-3 safety perfor- mance criteria for high-speed roadways. Previous research with short-radius systems had either been unable to meet the TL-3 safety criteria or had proven unable to meet the space requirements for many of the intersecting roadway sites, so there had been no effective method available for treating these sites for high-speed facilities. The objective of NCHRP Project 15-53, “Roadside Barrier Designs Near Bridge Ends with Restricted Rights of Way,” was to (1) review the history of limited space or short-radius barrier design and evolution; (2) develop a design and provide guidelines on a barrier safety treatment for use near bridge ends with restricted rights-of-way; (3) document efforts to advance the state of the practice for roadside safety hardware development; and (4) develop proposed language in a format suitable for potential adoption and inclusion in a future update to AASHTO’s Roadside Design Guide. In addition to NCHRP Research Report 1013, which summarizes the entire research effort, NCHRP Web-Only Document 334: Roadside Barrier Designs near Bridge Rail Ends with Restricted Rights-of-Way: A National Survey and Testing Reports includes appendices to the report that further detail the research conducted under this project. These materials are avail- able on the National Academies Press website (www.nap.edu) and can be found by searching for NCHRP Research Report 1013. F O R E W O R D By Christopher T. McKenney Staff Officer Transportation Research Board

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.nap.edu) retains the color versions. 1 Summary 5 Chapter 1 Introduction 5 1.1 Background 8 1.2 Research Objectives and Approach 8 1.3 Current Practices and Agency Concerns 10 1.4 Report Organization 11 Chapter 2 Conceptual Design for Improved Short-Radius Barrier 11 2.1 Design Concept Process 12 2.2 Finite Element Models 12 2.3 Impact Performance 13 2.4 Deeper Assessment of MGS-Based Concepts 24 2.5 Simulation Conclusions 27 Chapter 3 Crash-Test Results 27 3.1 Crash-Test Matrix 30 3.2 Evaluation Criteria 30 3.3 Test Facility: Federal Outdoor Impact Laboratory 32 3.4 Preliminary Full-Scale Crash Tests 32 3.5 SRGS Design 39 3.6 Full-Scale Crash Testing and Reporting 89 Chapter 4 Development of Guidelines on Application and Installation of SRGS 89 4.1 Research Questions 89 4.2 Application Guidelines 94 4.3 Installation Guidelines 98 Chapter 5 Overview and Conclusions 99 Bibliography C O N T E N T S