US Bridges

Mackinac Trail over I-75 NB

Fair

Chippewa County, Michigan · 2.9 MI S of M-28 · Structure no. 000000000001579

Built
1963
62 years old
Condition
Fair
inspected April 2023
Type
Stringer/Multi-beam or Girder
Steel
Length
352 ft
4 main spans
Daily traffic
1,000
2007 count
Owner
State
State Highway Agency

About this bridge

Mackinac Trail over I-75 NB is a steel stringer/multi-beam or girder carrying Mackinac Trail over I-75 NB in Chippewa County, Michigan. It was built in 1963, so it is 62 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 1,000 vehicles a day, projected to reach 1,100 by 2022. The structure is 352 ft (107.2 m) long and 33 ft wide. If it were closed, the detour would be 6.2 mi (10 km).

Location

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CarriesMackinac Trail
CrossesI-75 NB
Location2.9 MI S of M-28
RouteCounty Highway 0
CountyChippewa County
StateMichigan
Coordinates46.33619, -84.42799
Functional classRural Major Collector

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.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionApril 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourBridge not over waterway
Structural evaluation6: Equal to present minimum criteria
Deck geometry5: Somewhat better than minimum adequacy to tolerate being left in place as is
Approach roadway alignment7: Better than present minimum criteria
Operating rating75 US tons
Inventory rating45 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel
DeckConcrete, cast-in-place
Main spans4
Design loadH 15
Structure length352 ft (107.2 m)
Longest span100 ft (30.4 m)
Deck width33 ft (10 m)
Roadway width29 ft (8.8 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic1,000 (2007)
Projected traffic1,100 by 2022
Trucks—
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesHighway
Detour if closed6.2 mi (10 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 proposedDeck replacement with only incidental widening
Estimated improvement cost—
NavigationNot applicable (no waterway)

Frequently asked questions

When was Mackinac Trail over I-75 NB built?

It was built in 1963, making it 62 years old in 2025.

What condition is Mackinac Trail over I-75 NB 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 April 2023.

How much traffic does Mackinac Trail over I-75 NB carry?

About 1,000 vehicles per day (2007 count).

How long is Mackinac Trail over I-75 NB?

The structure is 352 ft (107.2 m) long with a longest span of 100 ft (30.4 m) and a deck 33 ft wide.

Who owns Mackinac Trail over I-75 NB?

It is owned by the State Highway Agency.