Research & Innovation

Optimized Pre-Tensioning and Re-Tightening Approaches for Anchor Rods for Highway Signs, Luminaires, and Traffic Signals (SLTS)

Summary:

Previous studies and field investigations have demonstrated that anchor rods at the base of structural posts for highway signs, luminaires, and traffic signals (SLTS) are susceptible to relaxation. This results in loosening of base connections and premature failure of such structural supports. On the other hand, re-tightening of anchor rods 48 hours after the installation requires significant resources, manpower, and additional costs. This implementation project aims to review past studies, systematically study the pre-tensioning methods and re-tightening procedures through experimental testing to fill the knowledge gap, and to propose an optimized method for pre-tensioning and re-tightening of anchor rod connections to result in acceptable relaxation, while minimizing the resources for doing so, and minimizing chances of over-tightening. In the end, the proposed methodology will be implemented in two local structural supports for SLTS in the state of Minnesota to evaluate the effectiveness of the proposed methodology.

Final Deliverables:

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Related Research:

Project Personnel:

Principal Investigator:  Pedram Mortazavi
Co-Principal Investigator:  Lauren Linderman, Jia-Liang Le
Technical Liaison:  Yuying Hu
Project Coordinator:  David Glyer
Panel Members: 
    Alexander Govrik - Traffic Engineering
    Douglas Maki - Asset Management
    Enhui Tan - Bridges
    Jihshya Lin - Bridges
    Steven McBurney - Traffic Engineering
    Susan Zarling - Traffic Engineering
    Thomas Dailey - Traffic Engineering