US Bridges

I-75 NB over Central ST

Fair

Emmet County, Michigan · In Mackinac City · Structure no. 000000000002454

Built
1957
68 years old, rebuilt 2005
Condition
Fair
inspected August 2024
Type
Stringer/Multi-beam or Girder
Steel
Length
130 ft
3 main spans
Daily traffic
10,100
2020 count
Owner
State
State Highway Agency

About this bridge

I-75 NB over Central ST is a steel stringer/multi-beam or girder carrying I-75 NB over Central ST in Emmet County, Michigan. It was built in 1957 and reconstructed in 2005, so it is 68 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 10,100 vehicles a day, roughly 12% of them trucks, projected to reach 11,050 by 2042. The structure is 130 ft (39.7 m) long and 81 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

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CarriesI-75 NB
CrossesCentral ST
LocationIn Mackinac City
RouteInterstate 75
CountyEmmet County
StateMichigan
Coordinates45.78159, -84.733
Functional classRural Principal Arterial - Interstate

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.
Substructure7 GoodSome minor problems.
Last inspectionAugust 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourBridge not over waterway
Structural evaluation6: Equal to present minimum criteria
Deck geometry9: Superior to present desirable criteria
Approach roadway alignment6: Equal to present minimum criteria
Operating rating98.5 US tons
Inventory rating59 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel
DeckConcrete, cast-in-place
Main spans3
Design loadHS 20
Structure length130 ft (39.7 m)
Longest span63 ft (19.3 m)
Deck width81 ft (24.8 m)
Roadway width73 ft (22.2 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic10,100 (2020)
Projected traffic11,050 by 2042
Trucks12%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesHighway
Detour if closed1.2 mi (2 km)
TollOn a free road
National Highway SystemYes
Strategic Highway NetworkInterstate STRAHNET route

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—
NavigationNot applicable (no waterway)

Frequently asked questions

When was I-75 NB over Central ST built?

It was built in 1957, making it 68 years old in 2025. It was reconstructed in 2005.

What condition is I-75 NB over Central ST 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 August 2024.

How much traffic does I-75 NB over Central ST carry?

About 10,100 vehicles per day (2020 count), of which roughly 12% are trucks.

How long is I-75 NB over Central ST?

The structure is 130 ft (39.7 m) long with a longest span of 63 ft (19.3 m) and a deck 81 ft wide.

Who owns I-75 NB over Central ST?

It is owned by the State Highway Agency.