CLOSE OVERLAY

Implementation of New Guidelines for Tightening Large Anchor Bolts of Support Structures for Signs and Luminaires

Project Details
STATUS

In-Progress

START DATE

10/11/18

END DATE

02/28/20

FOCUS AREAS

Safety

RESEARCH CENTERS InTrans
SPONSORS

Minnesota Department of Transportation

Researchers
Principal Investigator
An Chen

About the research

MnDOT is experiencing problems with loose nuts at the anchor bolts of various transportation structures including signs and luminaires. To address this issue, MnDOT funded a research project, which ended in June 2018. In this project, Iowa State University researchers developed specifications (including tables and charts) for tightening and re-tightening of anchor bolts. MnDOT will begin to implement these specifications in a project set to occur from October 2018 to December 2019.

With the to-be-obtained field performance data, this Phase II project will refine the specifications, along with completing other needed research to complete the specifications with regard to snug tight conditions, alternative bolt materials and sizes, grip lengths, continuing fatigue tests, collecting monitoring data, etc. All results will help to complete bolt tightening and re-tightening procedures and specifications that will eliminate or minimize problems associated with loose anchor bolt nuts in MnDOT structures, which will save construction and maintenance costs while simultaneously improving the safety of the traveling public.

The findings from this project will be proposed to the AASHTO T-12 Committee to change the bolt tightening procedures.

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