US Bridges

M-28 over Au Train River

Fair

Alger County, Michigan · E Limits of Au Train · Structure no. 000000000000047

Built
1932
93 years old, rebuilt 1976
Condition
Fair
inspected May 2024
Type
Stringer/Multi-beam or Girder
Steel
Length
150 ft
3 main spans
Daily traffic
5,200
2020 count
Owner
State
State Highway Agency

About this bridge

M-28 over Au Train River is a steel stringer/multi-beam or girder carrying M-28 over Au Train River in Alger County, Michigan. It was built in 1932 and reconstructed in 1976, so it is 93 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 5,200 vehicles a day, roughly 5% of them trucks, projected to reach 5,750 by 2040. The structure is 150 ft (45.7 m) long and 60 ft wide. If it were closed, the detour would be 29.2 mi (47 km).

Location

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CarriesM-28
CrossesAu Train River
LocationE Limits of Au Train
RouteState Highway 28
CountyAlger County
StateMichigan
Coordinates46.43312, -86.83623
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
Deck6 SatisfactoryStructural elements show some minor deterioration.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionMay 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourScour critical; foundations unstable for calculated scour conditions
Structural evaluation6: Equal to present minimum criteria
Deck geometry9: Superior to present desirable criteria
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment7: Better than present minimum criteria
Operating rating65.4 US tons
Inventory rating38.9 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel
DeckConcrete, cast-in-place
Main spans3
Design loadHS 20
Structure length150 ft (45.7 m)
Longest span49 ft (15 m)
Deck width60 ft (18.3 m)
Roadway width51 ft (15.4 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic5,200 (2020)
Projected traffic5,750 by 2040
Trucks5%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed29.2 mi (47 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 proposedDeck replacement with only incidental widening
Estimated improvement cost$34,000
NavigationNo navigation control on waterway

Frequently asked questions

When was M-28 over Au Train River built?

It was built in 1932, making it 93 years old in 2025. It was reconstructed in 1976.

What condition is M-28 over Au Train 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 May 2024.

How much traffic does M-28 over Au Train River carry?

About 5,200 vehicles per day (2020 count), of which roughly 5% are trucks.

How long is M-28 over Au Train River?

The structure is 150 ft (45.7 m) long with a longest span of 49 ft (15 m) and a deck 60 ft wide.

Who owns M-28 over Au Train River?

It is owned by the State Highway Agency.