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Au Sable River Bridge


File:M-72-Au Sable River Bridge A.jpg

Photo taken by Wikipedia user Andrew Jameson

License: Creative Commons Attribution-Share-Alike (CC BY-SA)

View this photo at en.m.wikipedia.org

BH Photo #275776


Street View 


Steel rigid frame bridge over Au Sable River on M-72 (Business I-75)
Grayling, Crawford County, Michigan
Open to traffic
Built 1935
Steel rigid frame
Span length: 40.0 ft.
Total length: 40.0 ft.
Deck width: 40.0 ft.
Posted to the National Register of Historic Places on December 9, 1999
Approximate latitude, longitude
+44.65979, -84.71250   (decimal degrees)
44°39'35" N, 84°42'45" W   (degrees°minutes'seconds")
Approximate UTM coordinates
16/681354/4947703 (zone/easting/northing)
Quadrangle map:
Average daily traffic (as of 2015)
Inventory numbers
NRHP 99001510 (National Register of Historic Places reference number)
MINEW 02031 (Michigan bridge number on the National Bridge Inventory 2011 and later)
BH 59902 (Bridgehunter.com ID)
Inspection report (as of May 2017)
Overall condition: Good
Superstructure condition rating: Very Good (8 out of 9)
Substructure condition rating: Good (7 out of 9)
Deck condition rating: Very Good (8 out of 9)
Sufficiency rating: 74.7 (out of 100)
View more at BridgeReports.com

Update Log 

  • February 24, 2014: Added by Dave King



Au Sable River Bridge
Posted April 5, 2016, by Nathan Holth (nathan [at] historicbridges [dot] org)

The shop riveting portion of the rehab/restoration job has been completed by Bach Steel.

Au Sable River Bridge
Posted March 30, 2016, by Nathan Holth (nathan [at] historicbridges [dot] org)

This little and easily overlooked historic bridge is about to take its place in preservation history as Bach Steel commences shop riveting on March 31, 2016 as part of the comprehensive rehabilitation of this historic bridge. This project will be the first active highway bridge to receive new rivets in Michigan in decades (all riveting projects in recent Michigan history were for pedestrian bridges).

Genuine, historically correct rivets rather than modern bolts should be considered the ONLY acceptable way to rehabilitate a riveted bridge in keeping with the Secretary of Interior's Standards for Rehabilitation. Michigan has taken the lead in historic bridge preservation by recognizing this fact, with a total of THREE active historic highway bridges in 2016 to be rehabilitated with riveting to be a part of the contract.

Other states DOTs and SHPOs need to take notice of Michigan and follow its lead, along with a growing number of states that have done projects with riveting. Riveting is safe, cost-effective, and the only way to rehabilitate riveted bridges in keeping with the Secretary of Interior's Standards for Rehabilitation.