Guidelines for Evaluating Crashworthiness of Sign Supports and Breakaway Luminaire Poles (2024)

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NCHRP Research Report 1123 Pre-Publication Draft— Subject to Revision Guidelines for Evaluating Crashworthiness of Sign Supports and Breakaway Luminaire Poles Mojdeh Asadollahi Pajouh Dhafer Marzougui Robert Bielenberg Fadi Tahan Ronald Faller Cing-Dao (Steve) Kan Cody Stolle Center for Collision Safety and Analysis Chen Fang George Mason University Riley Ruskamp Fairfax, VA Mohammadreza Rajaee Midwest Roadside Safety Facility University of Nebraska–Lincoln Lincoln, NE Submitted April 2024 DISCLAIMER The opinions and conclusions expressed or implied in this document are those of the researchers who performed the research. They are not necessarily those of the program sponsors; the FHWA; the Transportation Research Board; or the National Academies of Sciences, Engineering, and Medi- cine. The information contained in this document was taken directly from the submission of the au- thors. This material has not been edited by the Transportation Research Board. SPECIAL NOTE: This document IS NOT an official publication of the Transportation Research Board or the National Academies of Sciences, Engineering, and Medicine. A final, edited version of this document will be released at a later date. 

© 2024 by the National Academy of Sciences. National Academies of Sciences, Engineering, and Medicine and the graphical logo are trademarks of the National Academy of Sciences. All rights reserved. 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 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 initiated 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 Agreement No. 693JJ31950003. 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 endorsement by TRB and any of its program sponsors 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. DISCLAIMER To facilitate more timely dissemination of research findings, this pre-publication document is taken directly from the submission of the research agency. The material has not been edited by TRB. The opinions and conclusions expressed or implied in this document are those of the researchers who performed the research. They 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 specifications. 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, 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. This pre-publication document IS NOT an official publication of the Cooperative Research Programs; the Transportation Research Board; or the National Academies of Sciences, Engineering, and Medicine. Recommended citation: Pajouh, M. A., R. Bielenberg, R. Faller, C. Stolle, C. Fang, R. Ruskamp, M. Rajaee, D. Marzougui, F. Tahan, and C.-D. (Steve) Kan. Guidelines for Evaluating Crashworthiness of Sign Supports and Breakaway Luminaire Poles. Pre-publication draft of NCHRP Research Report 1123. Transportation Research Board, Washington, DC. 

NCHRP Research Report 1123 Guidelines for Evaluating Crashworthiness of Sign Supports and Breakaway Luminaire Poles Mojdeh Asadollahi Pajouh Robert Bielenberg Ronald Faller Cody Stolle Chen Fang Riley Ruskamp Mohammadreza Rajaee Midwest Roadside Safety Facility University of Nebraska–Lincoln Lincoln, NE Dhafer Marzougui Fadi Tahan Cing-Dao (Steve) Kan Center for Collision Safety and Analysis George Mason University Fairfax, VA April 2024 Subscriber Categories Highways ● Design ● Safety and Human Factors ii 

Author Acknowledgments This work was completed utilizing the Holland Computing Center of the University of Nebraska, which receives support from the UNL Office of Research and Economic Development and the Nebraska Research Initiative. Uncertainty of Measurement Statement The Midwest Roadside Safety Facility (MwRSF) and FHWA Federal Outdoor Impact Laboratory (FOIL) have determined the uncertainty of measurements for several parameters involved in standard full-scale crash testing and non-standard testing of roadside safety features. Information regarding the uncertainty of measurements for critical parameters is available upon request by the sponsor and the Federal Highway Administration. iii 

Contents Summary ......................................................................................................................................... 1 Chapter 1 - Introduction .................................................................................................................. 9 1.1. Background and Problem Statement ....................................................................... 9 1.2. Project Objectives & Scope .................................................................................. 10 1.3. Research Approach ............................................................................................... 10 1.4. Report Organization .............................................................................................. 15 Chapter 2 – Testing Program – Breakaway Luminaire Poles ....................................................... 16 2.1. Overview .................................................................................................................... 16 2.2. Test Requirements and Evaluation Criteria ............................................................... 20 2.3. Design Details ............................................................................................................ 22 2.4. Test Conditions .......................................................................................................... 52 2.5. Full-Scale Crash Test No. TBLP-1 ............................................................................ 59 2.6. Full-Scale Crash Test No. TBLP-2 ............................................................................ 74 Chapter 3 – Validating Analytical Program – Breakaway Luminaire Poles ................................ 89 3.1. Overview .................................................................................................................... 89 3.2. Updated LS-DYNA Models ...................................................................................... 89 3.3. Validation of LS-DYNA Simulation – Test No. TBLP-1 ......................................... 91 3.4. Validation of LS-DYNA Simulation – Test No. TBLP-2 ....................................... 101 3.5. Re-Validation of LS-DYNA Simulation – Pendulum Tests .................................... 110 3.6. Re-Validation of LS-DYNA Simulation – Pole Crash Tests NCHRP Project 03-119 ......................................................................................................................................... 119 3.7. Summary and Discussion ......................................................................................... 129 Chapter 4 – Testing Program – Breakaway Sign Supports – PSST Posts .................................. 130 4.1. Overview .................................................................................................................. 130 4.2. Test Requirements and Evaluation Criteria ............................................................. 131 4.3. Test Article and Installation Details ........................................................................ 132 iv 

4.4. Test Vehicles ............................................................................................................ 135 4.5. Crash Tests Outcome ............................................................................................... 135 Chapter 5 – Validating Analytical Program – Breakaway Sign Supports – PSST Posts ........... 147 5.1. FOIL Test Nos. 23004, 23006, 23008, 23010, and 23012....................................... 148 5.2. TTI Test Nos. 690900-XSD 4 through 690900-XSD 9 ........................................... 164 5.3. TTI Test 469469-07-02 ............................................................................................ 169 5.4. TTI Test RF476460-1-2-B ....................................................................................... 172 5.5. FOIL Component Test Nos. 19004A, 19004-B, 19004-C, and 19004-D ................ 175 Chapter 6 – Investigation of Luminaire Pole and PSST Crash Tests and Simulations .............. 178 6.1 Analysis of Luminaire Poles Supported by TB1-17 Transformer Base ................... 178 6.2 Analysis of Breakaway Sign Supports – PSST Posts ............................................... 202 Chapter 7 – Preliminary Draft Guidelines, Recommendations, and Proposed Modifications to MASH ......................................................................................................................................... 209 7.1 Luminaire Poles Supported by TB1-17 Transformer Base....................................... 209 7.2 Breakaway Sign Supports – PSST Posts .................................................................. 216 Chapter 8 – Summary and Conclusions ...................................................................................... 220 References ................................................................................................................................... 230 v