Evaluating the Performance of Guardrail Systems for Installation in Georgia by Driving Through Asphalt Layers

The preferred procedure for guardrail installation in the State of Georgia includes a layer of asphalt (usually referred to as a “mow strip”) placed to retard vegetation growth around the guardrail. The objective of this multi-phase research program is to develop effective alternatives to post installation methods that incorporate a leave-out around the post. The work described in this report represents Phase I of the overall research effort. The research team evaluated the structural performance of guardrail posts installed in accordance with current GDOT (Georgia Department of Transportation) procedures that include an asphalt mow strip, as well as alternative installation options developed in conjunction with GDOT personnel. The current state of practice related to the use of asphalt vegetation barriers in the United States was identified through on a nationwide survey. An experimental program was carried out in accordance with applicable American Association of State Highway and Transportation Officials (AASHTO) guidelines. In parallel with the experimental program, a three dimensional finite element model was developed for a guardrail post installed through an asphalt layer. Results from the experimental program and finite element analyses were used to develop a series of quantitative criteria to evaluate the performance of the various post/mow strip configurations. Parametric studies were conducted on pertinent geometric variables in terms of the quantitative performance criteria. The results of this Phase I research program demonstrate that (1) there are potential combinations of mow strip thickness and rear distance that are likely to result in satisfactory dynamic performance, and (2) two techniques appear effective in reducing the ground-level restraint imparted by a mow strip on a guardrail system: decreasing the mow strip rear distance behind the post, and pre-cutting the mow strip in the region behind the post.

• Record URL:
  http://g92018.eos-intl.net/eLibSQL14_G92018_Documents/13-21.pdf
• 
• Supplemental Notes:
  • Cover title: Evaluating the Performance of Guardrail Posts Installed by Driving Through Asphalt Layers.
• Corporate Authors:

  Georgia Institute of Technology, Atlanta

  School of Civil and Environmental Engineering
  Atlanta, GA  United States  30332

  Georgia Department of Transportation

  Office of Research, 15 Kennedy Drive
  Forest Park, GA  United States  30297-2534

  Federal Highway Administration

  1200 New Jersey Avenue, SE
  Washington, DC  United States  20590
• Authors:
  • Scott, David
  • White, Donald
  • Stewart, Lauren
  • Arson, Chloe
  • Bakhtiary, Esmaeel
  • Lee, Seo-Hun
• Publication Date: 2015-12-4

Language

• English

Media Info

• Media Type: Digital/other
• Edition: Final Report
• Features: Appendices; Figures; Photos; References; Tables;
• Pagination: 155p

Subject/Index Terms

• TRT Terms: Asphalt pavements; Evaluation; Finite element method; Guardrails; Installation; Posts; Roadside; State of the practice
• Geographic Terms: Georgia
• Subject Areas: Design; Highways; Safety and Human Factors; I85: Safety Devices used in Transport Infrastructure;

Filing Info

• Accession Number: 01590468
• Record Type: Publication
• Report/Paper Numbers: FHWA-GA-15-1321, 13-21
• Files: TRIS, ATRI, USDOT, STATEDOT
• Created Date: Feb 18 2016 9:26AM