US Bridges

M-72|M-93 over Au Sable River

Fair

Crawford County, Michigan · In Grayling · Structure no. 000000000002053

Built
1993
32 years old
Condition
Fair
inspected June 2023
Type
Box Beam or Girders - Multiple
Prestressed Concrete
Length
54 ft
1 main span
Daily traffic
11,731
2007 count
Owner
State
State Highway Agency

About this bridge

M-72|M-93 over Au Sable River is a prestressed concrete box beam or girders - multiple carrying M-72|M-93 over Au Sable River in Crawford County, Michigan. It was built in 1993, so it is 32 years old, younger than the Michigan average of 48.3 years.

The most recent inspection reported to the Federal Highway Administration rates it in fair condition with a lowest component rating of 5 out of 9. The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.

It carries about 11,731 vehicles a day, roughly 12% of them trucks, projected to reach 11,449 by 2018. The structure is 54 ft (16.5 m) long and 69 ft wide. If it were closed, the detour would be 8.7 mi (14 km).

Location

Open in Google Maps
CarriesM-72|M-93
CrossesAu Sable River
LocationIn Grayling
RouteState Highway 72
CountyCrawford County
StateMichigan
Coordinates44.65802, -84.72608
Functional classRural Principal Arterial - Other

Condition and inspection

Fair

The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.

ComponentRatingMeaning
Deck5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Superstructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection8 Very GoodNo problems noted.
Last inspectionJune 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour within limits of footing or piles
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Deck geometry5: Somewhat better than minimum adequacy to tolerate being left in place as is
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment7: Better than present minimum criteria
Operating rating91.4 US tons
Inventory rating54.7 US tons

Structure

Structure typeBox Beam or Girders - Multiple
MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans1
Design loadHS 25 or greater
Structure length54 ft (16.5 m)
Longest span53 ft (16.3 m)
Deck width69 ft (21 m)
Roadway width56 ft (17.1 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic11,731 (2007)
Projected traffic11,449 by 2018
Trucks12%
Lanes on structure4
Traffic directionTwo-way traffic
CarriesHighway and pedestrian
CrossesWaterway
Detour if closed8.7 mi (14 km)
TollOn a free road
National Highway SystemYes

Ownership and planned work

OwnerState Highway Agency
Maintained byState Highway Agency
Historic statusNot eligible for the National Register of Historic Places
Work proposedReplacement because of substandard load-carrying capacity or roadway geometry
Estimated improvement cost—
NavigationNo navigation control on waterway

Frequently asked questions

When was M-72|M-93 over Au Sable River built?

It was built in 1993, making it 32 years old in 2025.

What condition is M-72|M-93 over Au Sable River in?

The National Bridge Inventory rates it in fair condition. The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound. The last reported inspection was in June 2023.

How much traffic does M-72|M-93 over Au Sable River carry?

About 11,731 vehicles per day (2007 count), of which roughly 12% are trucks.

How long is M-72|M-93 over Au Sable River?

The structure is 54 ft (16.5 m) long with a longest span of 53 ft (16.3 m) and a deck 69 ft wide.

Who owns M-72|M-93 over Au Sable River?

It is owned by the State Highway Agency.