Initial Assessment of Compliance of Texas Roadside Safety Hardware with Proposed Update to ...

136 Pages·2007·40.81 MB·English

by  Texas Transportation Institute

Technical Report Documentation Page

1. Report No. 2. Government Accession No. 3. Recipient's Catalog No.
FHWA/TX-07/0-5526-1

4. Title and Subtitle 5. Report Date
INITIAL ASSESSMENT OF COMPLIANCE OF TEXAS April 2007
ROADSIDE SAFETY HARDWARE WITH PROPOSED UPDATE Published: September 2007

TO NCHRP REPORT 350
6. Performing Organization Code

7. Author(s) 8. Performing Organization Report No.
Roger P. Bligh and Wanda L. Menges Report 0-5526-1

9. Performing Organization Name and Address 10. Work Unit No. (TRAIS)
Texas Transportation Institute

The Texas A&M University System 11. Contract or Grant No.
College Station, Texas 77843-3135 Project 0-5526

1 2. Sponsoring Agency Name and Address 13. Type of Report and Period Covered
Texas Department of Transportation Technical Report:
Research and Technology Implementation Office September 2005 – August 2006

P.O. Box 5080 14. Sponsoring Agency Code
Austin, Texas 78763-5080

15. Supplementary Notes
Project performed in cooperation with the Texas Department of Transportation and the Federal Highway
Administration.
Project Title: Impact Performance Assessment of Roadside Safety Appurtenances
URL: http://tti.tamu.edu/documents/0-5526-1.pdf

16. Abstract
Guidelines for testing and evaluating the impact performance of roadside safety features are
periodically updated to stay current with improvements in technology and changes in the vehicle fleet and
impact conditions. NCHRP Report 350, which contains current recommendations for testing and evaluating
roadside safety devices, was published in 1993. Research to develop an update to NCHRP Report 350
(Update) has recently been completed under NCHRP Project 22-14(02).
Changes being proposed as part of the new guidelines include new design test vehicles, revised test
matrices, and revised impact conditions. These changes will likely necessitate the re-evaluation of the
impact performance of some existing roadside features. Under this project, researchers performed an initial
assessment regarding the ability of Texas roadside safety hardware to comply with the Update. The impact
performance assessment was based on crash test results, engineering analyses, and engineering judgment.
Categories of roadside appurtenances evaluated include guard fence, median barriers, bridge rails, precast
work zone barriers, breakaway sign supports, and work zone traffic control devices. Proprietary devices
such as crash cushions and guardrail end treatments were not considered.
The results of the performance assessment were used to prioritize additional testing and evaluation
required to bring Texas roadside safety features into compliance with the new impact performance
guidelines. This prioritization of hardware will help ensure efficient use of resources and provide a relatively
seamless transition to the Update.

17. Key Words 18. Distribution Statement
Roadside Safety, Crash Testing, Impact No restrictions. This document is available to the
Performance, Roadside Appurtenances, Guard public through NTIS:
Fence, Median Barriers, Bridge Rails, Precast Work National Technical Information Service
Zone Barriers, Breakaway Sign Supports, Work Springfield, Virginia 22161
Zone Traffic Control Devices http://www.ntis.gov

19. Security Classif.(of this report) 20. Security Classif.(of this page) 21. No. of Pages 22. Price
Unclassified Unclassified 136
Form DOT F 1700.7 (8-72) Reproduction of completed page authorized

INITIAL ASSESSMENT OF COMPLIANCE
OF TEXAS ROADSIDE SAFETY HARDWARE
WITH PROPOSED UPDATE TO NCHRP REPORT 350

by

Roger P. Bligh, Ph.D., P.E.
Research Engineer
Texas Transportation Institute

and

Wanda L. Menges
Associate Research Specialist
Texas Transportation Institute

Report 0-5526-1
Project 0-5526
Project Title: Impact Performance Assessment
of Roadside Safety Appurtenances

Performed in cooperation with the
Texas Department of Transportation
and the
Federal Highway Administration

April 2007
Published: September 2007

TEXAS TRANSPORTATION INSTITUTE
The Texas A&M University System
College Station, Texas 77843-3135

DISCLAIMER

The contents of this report reflect the views of the authors, who are responsible for the
facts and the accuracy of the data, and the opinions, findings, and conclusions presented herein.
The contents do not necessarily reflect the official view or policies of the Texas Department of
Transportation (TxDOT), Federal Highway Administration (FHWA), The Texas A&M
University System, or the Texas Transportation Institute. This report does not constitute a
standard, specification, or regulation, and its contents are not intended for construction, bidding,
or permit purposes. In addition, the above listed agencies assume no liability for its contents or
use thereof. The names of specific products or manufacturers listed herein do not imply
endorsement of those products or manufacturers. The engineer in charge of the project was
Roger P. Bligh, P.E. (Texas, #78550).
v
ACKNOWLEDGMENTS

This research project was conducted under a cooperative program between the Texas
Transportation Institute, the Texas Department of Transportation, and the Federal Highway
Administration. The TxDOT project director and project coordinator for this research was
Ms. Rory Meza, Design. The authors acknowledge and appreciate her guidance and assistance.
vi
TABLE OF CONTENTS

Page

LIST OF FIGURES.......................................................................................................................ix

LIST OF TABLES.........................................................................................................................xi

CHAPTER 1. INTRODUCTION..................................................................................................1
BACKGROUND........................................................................................................................1
OBJECTIVES/SCOPE OF RESEARCH...................................................................................4

CHAPTER 2. OVERVIEW OF PROPOSED UPDATE TO NCHRP REPORT 350...................7

CHAPTER 3. ASSESSMENT OF ROADSIDE SAFETY HARDWARE USED IN TEXAS .11
GENERAL PERFORMANCE CONSIDERATIONS..............................................................11
Structural Adequacy..............................................................................................................13
Vehicle Stability....................................................................................................................16
Occupant Compartment Deformation...................................................................................17
METAL BEAM GUARD FENCE...........................................................................................19
MEDIAN BARRIERS..............................................................................................................21
PORTABLE AND PRECAST CONCRETE MEDIAN BARRIER........................................25
Precast F-Shape Concrete Median Barrier with Type X Connection...................................25
Low Profile Barrier...............................................................................................................28
TRANSITIONS........................................................................................................................29
TL-3 Transition.....................................................................................................................30
TL-2 Transition.....................................................................................................................31
BRIDGE RAILS.......................................................................................................................33
WORK-ZONE TRAFFIC CONTROL DEVICES...................................................................42
CRASH CUSHIONS AND GUARDRAIL END TREATMENTS.........................................46

CHAPTER 4. FULL-SCALE CRASH TESTING OF SMALL SIGN SUPPORTS...................49
WEDGE ANCHOR SYSTEM (CRASH TEST 455266-1)......................................................50
Test Article Design and Construction...................................................................................50
Test Vehicle..........................................................................................................................53
Weather Conditions..............................................................................................................53
Test Description....................................................................................................................53
Test Article Damage.............................................................................................................56
Test Vehicle Damage............................................................................................................56
Occupant Risk Values...........................................................................................................56
Assessment of Test Results...................................................................................................62
Summary of Test Results......................................................................................................64
Discussion.............................................................................................................................64
vii
TABLE OF CONTENTS (CONTINUED)

Page

TRIANGULAR SLIP BASE AND WEDGE ANCHOR SYSTEMS (TEST 455266-2).........65
Test Article Design and Construction...................................................................................65
Test Vehicle..........................................................................................................................66
Weather Conditions..............................................................................................................66
Test Description....................................................................................................................66
Test Article Damage.............................................................................................................71
Test Vehicle Damage............................................................................................................71
Occupant Risk Values...........................................................................................................76
Assessment of Test Results...................................................................................................76
Summary of Test Results......................................................................................................79
Discussion.............................................................................................................................80

CHAPTER 5. PRIORITIZATION OF TESTING NEEDS.........................................................81
DISCUSSION...........................................................................................................................85

CHAPTER 6. SUMMARY AND CONCLUSIONS...................................................................87

CHAPTER 7. IMPLEMENTATION STATEMENT..................................................................91

REFERENCES.............................................................................................................................93

APPENDIX A. TEST PROCEDURES.......................................................................................97
TEST FACILITY......................................................................................................................97
VEHICLE TOW AND GUIDANCE SYSTEM.......................................................................97
DATA ACQUISITION SYSTEMS..........................................................................................97
Vehicle Instrumentation and Data Processing......................................................................97
Photographic Instrumentation and Data Processing.............................................................98

APPENDIX B. CRASH TEST NO. 455266-1..........................................................................101
B1. VEHICLE PROPERTIES AND INFORMATION.........................................................101
B2. SEQUENTIAL PHOTOGRAPHS..................................................................................104
B3. VEHICLE ANGULAR DISPLACEMENTS.................................................................104
B4. VEHCILE ACCELERATIONS......................................................................................105

APPENDIX C. CRASH TEST NO. 455266-2..........................................................................113
C1. VEHICLE PROPERTIES AND INFORMATION.........................................................113
C2. SEQUENTIAL PHOTOGRAPHS..................................................................................116
C3. VEHICLE ANGULAR DISPLACEMENTS.................................................................116
C4. VEHICLE ACCELERATIONS......................................................................................117

viii
LIST OF FIGURES

Page

Figure 3-1. Yield Line Failure Analysis for Concrete Parapet (9)............................................13
Figure 3-2. Typical Cross Section of Metal Beam Guard Fence...............................................20
Figure 3-3. Typical Cross Section of F-Shape Concrete Safety Barrier....................................22
Figure 3-4. Cross Section of Single Slope Concrete Barrier.....................................................23
Figure 3-5. F-Shape Concrete Safety Barrier with X-Bolt Connection.....................................26
Figure 3-6. Cross-Section of Low-Profile Barrier Segment......................................................28
Figure 3-7. Elevation of Texas TL-3 Guardrail-to-Concrete Bridge Rail Transition................31
Figure 3-8. Photo of Texas TL-2 Guardrail-to-Concrete Bridge Rail Transition......................32
Figure 3-9. Cross Section of T101 Bridge Rail.........................................................................36
Figure 3-10. Cross Section of T203 Bridge Rail.........................................................................36
Figure 3-11. Cross Section of T6 Bridge Rail.............................................................................37
Figure 3-12. Cross Section of T501 Bridge Rail.........................................................................39
Figure 3-13. Cross Section of Single Slope Traffic Rail.............................................................39
Figure 3-14. Cross Section of T221 Bridge Rail.........................................................................40
Figure 3-15. Cross Section of T401 Bridge Rail.........................................................................41
Figure 3-16. Cross Section of T77 Bridge Rail...........................................................................41
Figure 3-17. High-Mounting Height Sign Support with Wood Uprights....................................45
Figure 3-18. High-Mounting Height Sign Support with Perforated Steel Tube Uprights...........47
Figure 4-1. Details of the Wedge Anchor Sign Support System...............................................51
Figure 4-2. Test Article/Installation before Test 455266-1.......................................................52
Figure 4-3. Vehicle/Installation Geometrics for Test 455266-1................................................54
Figure 4-4. Vehicle before Test 455266-1.................................................................................55
Figure 4-5. After Impact Trajectory Path for Test 455266-1.....................................................57
Figure 4-6. Installation after Test 455266-1..............................................................................58
Figure 4-7. Vehicle after Test 455266-1....................................................................................59
Figure 4-8. Interior of Vehicle for Test 455266-1.....................................................................60
Figure 4-9. Summary of Results for NCHRP Report 350 Update Test 3-62 on the Wedge
Anchor Sign Support..............................................................................................61
Figure 4-10. Details of the Triangular Slip Base Sign Support...................................................67
Figure 4-11. Test Article/Installation before Test 455266-2.......................................................68
Figure 4-12. Vehicle/Installation Geometrics for Test 455266-2................................................69
Figure 4-13. Vehicle before Test 455266-2.................................................................................70
Figure 4-14. After Impact Trajectory Path for Test 455266-2.....................................................72
Figure 4-15. Installation after Test 455266-2..............................................................................73
Figure 4-16. Vehicle after Test 455266-2....................................................................................74
Figure 4-17. Interior of Vehicle after Test 455266-2..................................................................75
Figure 4-18. Summary of Results for NCHRP Report 350 Update Test 3-62
on the Slip Base and Wedge Sign Supports...........................................................77
ix
LIST OF FIGURES (CONTINUED)

Page

Figure B1-1. Vehicle Properties for Test No. 455266-1............................................................101
Figure B2-1. Sequential Photographs for Test 455266-1
(Oblique and Perpendicular Views)....................................................................104
Figure B3-1. Vehicle Angular Displacements for Test 455266-1.............................................106
Figure B4-1. Vehicle Longitudinal Accelerometer Trace for Test 455266-1
(Accelerometer Located at Center of Gravity)....................................................107
Figure B4-2. Vehicle Lateral Accelerometer Trace for Test 455266-1
(Accelerometer Located at Center of Gravity)....................................................108
Figure B4-3. Vehicle Vertical Accelerometer Trace for Test 455266-1
(Accelerometer Located at Center of Gravity)....................................................109
Figure B4-4. Vehicle Longitudinal Accelerometer Trace for Test 455266-1
(Accelerometer Located over Rear Axle)............................................................110
Figure B4-5. Vehicle Lateral Accelerometer Trace for Test 455266-1
(Accelerometer Located over Rear Axle)............................................................111
Figure B4-6. Vehicle Vertical Accelerometer Trace for Test 455266-1
(Accelerometer Located over Rear Axle)............................................................112
Figure C1-1. Vehicle Properties for Test No. 455266-2............................................................113
Figure C2-1. Sequential Photographs for Test 455266-2
(Oblique and Perpendicular Views)....................................................................116
Figure C3-1. Vehicle Angular Displacements for Test 455266-2.............................................118
Figure C4-1. Vehicle Longitudinal Accelerometer Trace for Test 455266-2
(Accelerometer Located at Center of Gravity)....................................................119
Figure C4-2. Vehicle Lateral Accelerometer Trace for Test 455266-2
(Accelerometer Located at Center of Gravity)....................................................120
Figure C4-3. Vehicle Vertical Accelerometer Trace for Test 455266-2
(Accelerometer Located at Center of Gravity)....................................................121
Figure C4-4. Vehicle Longitudinal Accelerometer Trace for Test 455266-2
(Accelerometer Located over Rear Axle)............................................................122
Figure C4-5. Vehicle Lateral Accelerometer Trace for Test 455266-2
(Accelerometer Located over Rear Axle)............................................................123
Figure C4-6. Vehicle Vertical Accelerometer Trace for Test 455266-2
(Accelerometer Located over Rear Axle)............................................................124

x