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U.S. 23 Au Sable Bridge (Old)



Lost Pratt through truss bridge over Au Sable River on U.S. 23
Au Sable, Iosco County, Michigan
Replaced by a new bridge
Pratt through truss
Approximate latitude, longitude
+44.40730, -83.32476   (decimal degrees)
44°24'26" N, 83°19'29" W   (degrees°minutes'seconds")
Approximate UTM coordinates
17/314893/4919740 (zone/easting/northing)
Inventory number
BH 86796 (Bridgehunter.com ID)

Update Log 

  • September 30, 2019: Added by Mike Kerkau

Related Bridges 



U.S. 23 Au Sable Bridge (Old)
Posted November 1, 2019, by Anonymous

I looked them both over Mike, and while the portal bracing does appear to be very similar the sway bracing is quite different. And while that doesn't necessarily rule out Joliet as a possible fabricator, I have seen a few different firms use the large Lattice or X style portal bracing.

I'm wondering with this being a ca. 1920 bridge on a US road if it might be an early state designed structure. Nathan is far more versed in Michigan bridges than I, so he might have some input on it.

U.S. 23 Au Sable Bridge (Old)
Posted November 1, 2019, by Mike Kerkau (mjkerkau [at] gmail [dot] com)

Question, probably for Tony.

Those top panels at either entrance to this bridge - are those distinctive enough that they're identifiable of only one builder? Or would this have been a standard enough design that it could have been anyone?

Reason I ask is - it just clicked in my head. The Currie Parkway bridge in Midland County has these same distinctive top panels at the entrances, and that one is identified as a Joliet (original) build. Is that enough to say that this one was, too?