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2019 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 894 Performance of Longitudinal Barriers on Curved, Superelevated Roadway Sections Dhafer Marzougui Cing-Dao âSteveâ Kan Umashankar Mahadevaiah Fadi Tahan Christopher Story Stefano Dolci Alberto Moreno Center for Collision safety and analysis (CCsa) GeorGe Mason University Fairfax, VA Kenneth S. Opiela ConsUltant Springfield, VA Richard Powers ConsUltant Herndon, VA Subscriber Categories Construction â¢ Design â¢ Safety and Human Factors 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, 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 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 transportation results in increasingly complex problems of wide interest 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 techniquesâthe 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 TRBâs 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; TRBâs 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&Iâs recommendations are proposed to the AASHTO Board of Direc- tors and the National Academies. Research projects to address these topics 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 894 Project 22-29A ISSN 2572-3766 (Print) ISSN 2572-3774 (Online) ISBN 978-0-309-48012-3 Library of Congress Control Number 2019931195 Â© 2019 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 manufacturersâ 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 Boardâs 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 George Mason University Research Team wishes to cite its gratitude for contributions to this effort to consultant Dr. Kenneth S. Opiela. His expertise and experience provided invaluable perspectives on barrier design, evaluation, and deployment to maximize their potential to enhance highway safety. Special thanks is also given to the FHWA Office of Safety R&D for allowing testing at the Federal Outdoor Impact Laboratory (FOIL) and to Mr. Eduardo Arispe, who handled all the details to make this possible. The testing addressed questions related to longitudinal barriers deployed on curved, superelevated roadway sections. The Team thanks Gregory Industries (Mr. Andrew Artar) for supplying the test article material for the crash tests conducted under this project and the many individuals from state DOTs, industry, and academia who provided insights, information, and data that was used in this project. CRP STAFF FOR NCHRP RESEARCH REPORT 894 Christopher J. Hedges, Director, Cooperative Research Programs Lori L. Sundstrom, Deputy Director, Cooperative Research Programs Edward T. Harrigan, Senior Program Officer Sheila A. Moore, Program Associate Eileen P. Delaney, Director of Publications Natalie Barnes, Associate Director of Publications Kami Cabral, Editor NCHRP PROJECT 22-29A PANEL Field of DesignâArea of Vehicle Barrier Systems Chris Poole, Iowa DOT, Ames, IA (Chair) John C. Durkos, Road Systems, Inc., Stow, OH Lyman L. âTerryâ Hale, III, New York State DOT, Gansevoort, NY Charles F. McDevitt, McDevitt Consulting, Matthews, NC David S. Rayburn, National Transportation Safety Board, Washington, DC Michael J. Smelker, New Mexico DOT, Las Cruces, NM Teri Soos, Maryland State Highway Administration, Frederick, MD Ana Eigen, FHWA Liaison Stephen F. Maher, TRB Liaison
F O R E W O R D This report presents guidance on designing, selecting, and installing longitudinal traffic barriers for curved, superelevated roadways for possible incorporation in the AASHTO Roadside Design Guide. The report will be of immediate interest to engineers in state highway agencies with responsibility for design and selection of roadway barrier systems. Curved, high-speed roadways are usually superelevated to make the curved roadway easier for vehicles to navigate. Several potential concerns and uncertainties arise when longitudinal barriers are installed on curved, superelevated roadway sections (CSRS). Roadway curvature increases the angle of impact of a vehicle with respect to the barrier. This angle increase can cause an increase in impact loading that may potentially exceed the capacity of barriers designed for impacts along tangent roadway sections. Measures of occupant risk may also increase in magnitude. The objective of this research was to develop guidance for highway agencies on the design, selection, and installation of longitudinal traffic barriers on CSRS. The research was performed by George Mason University, Fairfax, Virginia, with the support of the FHWAâs Federal Outdoor Impact Laboratory (FOIL) at the Turner-Fairbank Highway Research Center, McLean, Virginia. The research encompassed extensive vehicle dynamics and finite element analyses of vehicle-barrier impacts on CSRS. The analyses were conducted for several different vehicle and barrier types, and for a range of roadway curvature and superelevation; shoulder width and angle; roadside slope; and barrier orientation and placement. The results of the com- puter analyses were validated by crash tests at the FHWAâs FOIL with full-size extended-cab pickup trucks impacting W-beam guardrail on CSRS. The practical outcome of the project is guidance for the AASHTO Technical Commit- tee on Roadside Safety on the design, selection, and installation of longitudinal barriers on CSRS. This guidance is summarized in Table 8.1 of the report, along with its implications for the design, selection, and installation of concrete and W-beam barriers on CSRS. This report fully documents the research. The following five appendices can be found on the TRB website (www.TRB.org) by searching for âNCHRP Research Report 894â: Appendix A: State DOT Survey Instrument and Instructions; Appendix B: Vehicle Dynam- ics Simulation Results; Appendix C: Finite Element Model Validations; Appendix D: Finite Element Simulation Results; and Appendix E: Full-Scale Crash Testing Report. By Edward T. Harrigan Staff Officer Transportation Research Board
C O N T E N T S 1 Summary 14 Chapter 1 Introduction 14 1.1 Background 15 1.2 Project Objectives and Scope 16 1.3 Research Approach 17 1.4 Report Organization 18 Chapter 2 Literature Review and State DOT Survey 18 2.1 Introduction 18 2.2 Barrier Crashworthiness Research 20 2.3 Terrain Effect Studies 23 2.4 General Curve Safety Guidance 24 2.5 Road Design Guidelines 27 2.6 State DOT Survey Results 30 2.7 Summary 31 Chapter 3 Crash Data Analysis 31 3.1 NASS/CDS Data Analyses 35 3.2 NASS/GES Data Analyses 38 3.3 FARS Data Analysis 41 3.4 NCHRP Project 17-22 Data Analysis 42 3.5 Data Analysis Summary 44 Chapter 4 Vehicle Dynamics Analysis for Vehicles Leaving the Traveled Way on CSRS 44 4.1 Background 45 4.2 Objective 45 4.3 Research Approach 46 4.4 VDA Considerations 50 4.5 VDA Simulation Results 57 4.6 Conclusions 58 Chapter 5 Crash Simulation Analysis of Impacts into Longitudinal Barriers on CSRS 58 5.1 Introduction 58 5.2 Background 58 5.3 FE Modeling and Crash Simulation Analyses 66 5.4 Computer Model Validations 71 5.5 Crash Simulation Parameters 73 5.6 Crash Simulation Results 82 5.7 Conclusions
86 Chapter 6 Full-Scale Testing and Results 86 6.1 Introduction 86 6.2 Background 88 6.3 Testing Requirements, Criteria, and Facility 89 6.4 Testing Approach 95 6.5 Preliminary Tests 97 6.6 Full-Scale Crash Testing Results 106 6.7 Test Results Evaluation 111 6.8 Conclusions 112 Chapter 7 Development of Guidance for Improved Longitudinal Barrier Design, Selection, and Installation on CSRS 112 7.1 Background 112 7.2 Research Questions 114 7.3 Summary of Findings 114 7.4 Translating Findings and Observations into Guidance 118 Chapter 8 Conclusions 119 8.1 Proposed Guidance 119 8.2 Implications for Current Practice 121 8.3 Needs for Future Research 122 References 124 Appendix A State DOT Survey Instrument and Instructions 125 Appendix B Vehicle Dynamics Simulation Results 126 Appendix C Finite Element Model Validations 127 Appendix D Finite Element Simulation Results 128 Appendix E Full-Scale Crash Testing Report