US Bridges

M-55 over Au Gres River

Fair

Ogemaw County, Michigan · 1.4 MI W of Iosco CO Line · Structure no. 000000000008416

Built
1929
96 years old, rebuilt 1992
Condition
Fair
inspected October 2023
Type
Stringer/Multi-beam or Girder
Prestressed Concrete
Length
35 ft
1 main span
Daily traffic
3,875
2022 count
Owner
State
State Highway Agency

About this bridge

M-55 over Au Gres River is a prestressed concrete stringer/multi-beam or girder carrying M-55 over Au Gres River in Ogemaw County, Michigan. It was built in 1929 and reconstructed in 1992, so it is 96 years old, older 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 6 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 3,875 vehicles a day, roughly 8% of them trucks, projected to reach 4,500 by 2042. The structure is 35 ft (10.7 m) long and 45 ft wide. If it were closed, the detour would be 14.9 mi (24 km).

Location

Open in Google Maps
CarriesM-55
CrossesAu Gres River
Location1.4 MI W of Iosco CO Line
RouteState Highway 55
CountyOgemaw County
StateMichigan
Coordinates44.27711, -83.90953
Functional classRural Minor Arterial

Condition and inspection

Fair

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

ComponentRatingMeaning
Deck7 GoodSome minor problems.
Superstructure8 Very GoodNo problems noted.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Last inspectionOctober 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourCountermeasures installed to correct a previously existing problem
Structural evaluation6: Equal to present minimum criteria
Deck geometry6: Equal to present minimum criteria
Waterway adequacy5: Somewhat better than minimum adequacy to tolerate being left in place as is
Approach roadway alignment6: Equal to present minimum criteria
Operating rating64.3 US tons
Inventory rating38.6 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans1
Design loadHS 20
Structure length35 ft (10.7 m)
Longest span32 ft (9.8 m)
Deck width45 ft (13.8 m)
Roadway width42 ft (12.8 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic3,875 (2022)
Projected traffic4,500 by 2042
Trucks8%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed14.9 mi (24 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerState Highway Agency
Maintained byState Highway Agency
Historic statusNot eligible for the National Register of Historic Places
Work proposedNone recorded
Estimated improvement cost—
NavigationNo navigation control on waterway

Frequently asked questions

When was M-55 over Au Gres River built?

It was built in 1929, making it 96 years old in 2025. It was reconstructed in 1992.

What condition is M-55 over Au Gres 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 October 2023.

How much traffic does M-55 over Au Gres River carry?

About 3,875 vehicles per day (2022 count), of which roughly 8% are trucks.

How long is M-55 over Au Gres River?

The structure is 35 ft (10.7 m) long with a longest span of 32 ft (9.8 m) and a deck 45 ft wide.

Who owns M-55 over Au Gres River?

It is owned by the State Highway Agency.