Investigation of Material Requirements for Highway Guardrail Systems (2022) / Chapter Skim
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112 Introduction Many guardrail failures are a result of the corrugated rail element rupturing during vehicle collisions. Several examples of such failures have been documented in full-scale crash-test reports (Buth et al.
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Review of Mechanical Properties for Corrugated Sheet Steel Used in Guardrail Field Installations 113 elongation was 61% less than that of the transition beam (19.8% versus 32%)
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114 Investigation of Material Requirements for Highway Guardrail Systems Notes: * Report not published; values not available; MGS = Midwest Guardrail System.
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Review of Mechanical Properties for Corrugated Sheet Steel Used in Guardrail Field Installations 115 Heat#= 209337 Yield = 61740 psi Tensile= 79690 psi %elong.= 26 % Figure G-4. Rail rupture at post-bolt in Test 469468-12-1 (Source: Bligh et al.
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116 Investigation of Material Requirements for Highway Guardrail Systems The issue of ductility was also corroborated by members of prominent full-scale crash-test organizations [i.e., TTI, MwRSF, and the Center for Collision Safety and Analysis (CCSA)
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Review of Mechanical Properties for Corrugated Sheet Steel Used in Guardrail Field Installations 117 Objective The research team reviewed the material properties of corrugated sheet steel used in guardrail to determine if changes are warranted for mechanical property specifications in M 180, and if such changes are practical. The current mechanical property specifications for corrugated sheet steel in M 180-18 were summarized in Table G-1.
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118 Investigation of Material Requirements for Highway Guardrail Systems Although this methodology does not provide precise calculation of strain energy, the pseudo- strain energy value should represent a reasonable comparison of material toughness between the various heats, since the stress–strain curves for each material heat for M 180 guardrail are expected to have the same basic shape. Results General Statistics A summary of material property statistics for M 180 W-beam rail from the data collected in this study is shown in Table G-3, with additional details provided in Addendum G-1.
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Review of Mechanical Properties for Corrugated Sheet Steel Used in Guardrail Field Installations 119 Yield Tensile σε (psi)
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120 Investigation of Material Requirements for Highway Guardrail Systems As shown in the cross-plots in Addenda G-1 and G-2, several of the mechanical properties exhibited a moderate-to-strong linear relationship with each other, while others showed weak or no relationship at all. For example, tensile strength had a moderate-to-strong correlation with yield strength, but had a weak correlation to percent elongation, and had no correlation to T/Y ratio or strain energy.
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Review of Mechanical Properties for Corrugated Sheet Steel Used in Guardrail Field Installations 121 strong correlation with material toughness (i.e., pseudo-strain energy) was percent elongation, with a positive correlation R2 value of 0.85.
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122 Investigation of Material Requirements for Highway Guardrail Systems minimum pseudo-strain energy value 33% compared to current specifications, as illustrated in the calculations that follow. Current baseline properties (70–50–12)
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Review of Mechanical Properties for Corrugated Sheet Steel Used in Guardrail Field Installations 123 tensile strength increases, as shown in Figure G-13 in Addendum G-1, and the additional cost to produce the high-strength, low-alloy (HSLA) chemistry needed for higher strength levels while achieving high elongation may not be reasonable.
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124 Investigation of Material Requirements for Highway Guardrail Systems Bullard, D.L., Jr., Bligh, R.P., Menges, W.L., and Haug, R.R. NCHRP Web-Only Document 157: Volume I: Evaluation of Existing Roadside Safety Hardware Using Updated Criteria -- Technical Report.
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Review of Mechanical Properties for Corrugated Sheet Steel Used in Guardrail Field Installations 125 Yield Tensile σε (psi)
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126 Investigation of Material Requirements for Highway Guardrail Systems Yield Tensile σε (psi)
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Review of Mechanical Properties for Corrugated Sheet Steel Used in Guardrail Field Installations 127 Yield Tensile σε (psi)
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128 Investigation of Material Requirements for Highway Guardrail Systems Yield Tensile σε (psi)
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Review of Mechanical Properties for Corrugated Sheet Steel Used in Guardrail Field Installations 129 Figure G-16. Statistics pertaining to pseudo-strain energy of M 180 W-beam guardrail.
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130 Investigation of Material Requirements for Highway Guardrail Systems § http://www.dmstat1.com/res/TheCorrelationCoefficientDefined.html#:~:text=Values%20between%200.7%20and%201.0,shared%20between%20the%20two %20variables.%E2%80%9D Figure G-17. Strength of linear correlation between material attributes of M 180 W-beam guardrail.
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Review of Mechanical Properties for Corrugated Sheet Steel Used in Guardrail Field Installations 131 Yield Tensile σε (psi)
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132 Investigation of Material Requirements for Highway Guardrail Systems Yield Tensile σε (psi)
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Review of Mechanical Properties for Corrugated Sheet Steel Used in Guardrail Field Installations 133 Yield Tensile σε (psi)
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134 Investigation of Material Requirements for Highway Guardrail Systems Yield Tensile σε (psi)
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Review of Mechanical Properties for Corrugated Sheet Steel Used in Guardrail Field Installations 135 Yield Tensile σε (psi)
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136 Investigation of Material Requirements for Highway Guardrail Systems § http://www.dmstat1.com/res/TheCorrelationCoefficientDefined.html#:~:text=Values%20between%200.7%20and%201.0,shared%20between%20the%20two %20variables.%E2%80%9D Figure G-23. Strength of linear correlation between material attributes of M 180 thrie-beam guardrail.
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Abbreviations and acronyms used without denitions in TRB publications: A4A Airlines for America AAAE American Association of Airport Executives AASHO American Association of State Highway Officials AASHTO American Association of State Highway and Transportation Officials ACI–NA Airports Council International–North America ACRP Airport Cooperative Research Program ADA Americans with Disabilities Act APTA American Public Transportation Association ASCE American Society of Civil Engineers ASME American Society of Mechanical Engineers ASTM American Society for Testing and Materials ATA American Trucking Associations CTAA Community Transportation Association of America CTBSSP Commercial Truck and Bus Safety Synthesis Program DHS Department of Homeland Security DOE Department of Energy EPA Environmental Protection Agency FAA Federal Aviation Administration FAST Fixing America's Surface Transportation Act (2015) FHWA Federal Highway Administration FMCSA Federal Motor Carrier Safety Administration FRA Federal Railroad Administration FTA Federal Transit Administration GHSA Governors Highway Safety Association HMCRP Hazardous Materials Cooperative Research Program IEEE Institute of Electrical and Electronics Engineers ISTEA Intermodal Surface Transportation Efficiency Act of 1991 ITE Institute of Transportation Engineers MAP-21 Moving Ahead for Progress in the 21st Century Act (2012)
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Transportation Research Board 500 Fifth Street, NW Washington, DC 20001 ADDRESS SERVICE REQUESTED ISBN 978-0-309-68758-4 9 7 8 0 3 0 9 6 8 7 5 8 4 9 0 0 0 0
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