Fatigue-Resistant Design for Overhead Signs, Mast-Arm Signal Poles, and Lighting Standards

Traffic signs and signals are often supported by flexible cantilevered structures that are susceptible to wind-induced vibration and fatigue. The latest version of the design specifications published by the American Association of State Transportation Officials (AASHTO) now considers fatigue as a limit state. However, most of the fatigue classifications for welded details were not based on full-scale testing, and are thought to be overly conservative. This research will address the fatigue resistance of two common mast arm-to-pole connections used in the state of Minnesota. The resistance attained experimentally aligned with current predictions using AASHTO procedures, except for in-plane loading of box connection details. As a consequence of specimen design, a variety of tube-to-transverse plate connections were also tested using multi-sided tube cross-sections with different tube diameters, tube thicknesses, as well as base plate thicknesses. The standard tube-to-transverse plate connection exhibited Category K sub 2 resistance, two categories lower than the E’ specified by AASHTO. This resistance was enhanced to Category E’ through impact treatment or Category E by doubling the base plate thickness. Gusset plates could not prevent cracking of the tube at the base plate, but the tips of the gusset plate exhibited Category E resistance.

• Record URL:
  • https://hdl.handle.net/20.500.14153/mndot.2619
• Record URL:
  • http://www.dot.state.mn.us/research/TS/2006/200607.pdf
• 
• Corporate Authors:

  University of Minnesota, Twin Cities

  Department of Civil Engineering, 500 Pillsbury Drive, SE
  Minneapolis, MN  United States  55455

  Minnesota Department of Transportation

  395 John Ireland Boulevard
  St Paul, MN  United States  55155
• Authors:
  • Ocel, Justin M
  • Dexter, Robert J
  • Hajjar, Jerome F
• Publication Date: 2006-3

Language

• English

Media Info

• Media Type: Web
• Edition: Final Report
• Features: Appendices; Figures; Photos; References; Tables;
• Pagination: 190p

Subject/Index Terms

• TRT Terms: Cracking; Design; Gusset plates; Mechanical fatigue; Mechanical resistance; Sign supports; Structural connection; Thickness
• Identifier Terms: American Association of State Highway and Transportation Officials
• Uncontrolled Terms: Box connection; Cantilevered traffic structures; Signal mast arms; Socket connection; Traffic signal supports
• Geographic Terms: Minnesota
• Subject Areas: Design; Highways; I20: Design and Planning of Transport Infrastructure;

Filing Info

• Accession Number: 01030736
• Record Type: Publication
• Report/Paper Numbers: MN/RC-2006-07
• Contract Numbers: (c) 81655 (wo) 59
• Files: TRIS, STATEDOT
• Created Date: Aug 14 2006 4:22PM