US Bridges

I-75 NB over Pine River

Fair

Mackinac County, Michigan · 3.6 MI S of Chippewa Col · Structure no. 000000000005940

Built
1963
62 years old
Condition
Fair
inspected December 2024
Type
Stringer/Multi-beam or Girder
Steel
Length
521 ft
9 main spans
Daily traffic
1,508
2007 count
Owner
State
State Highway Agency

About this bridge

I-75 NB over Pine River is a steel stringer/multi-beam or girder carrying I-75 NB over Pine River in Mackinac 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 1,508 vehicles a day, roughly 10% of them trucks, projected to reach 4,117 by 2018. The structure is 521 ft (158.8 m) long and 36 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

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CarriesI-75 NB
CrossesPine River
Location3.6 MI S of Chippewa Col
RouteInterstate 75
CountyMackinac County
StateMichigan
Coordinates46.12419, -84.61372
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.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionDecember 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour within limits of footing or piles
Structural evaluation6: Equal to present minimum criteria
Deck geometry4: Meets minimum tolerable limits to be left in place as is
Waterway adequacy9: Superior to present desirable criteria
Approach roadway alignment7: Better than present minimum criteria
Operating rating93.3 US tons
Inventory rating55.7 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel
DeckConcrete, cast-in-place
Main spans9
Design loadHS 20 + Mod
Structure length521 ft (158.8 m)
Longest span58 ft (17.7 m)
Deck width36 ft (11.1 m)
Roadway width31 ft (9.4 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic1,508 (2007)
Projected traffic4,117 by 2018
Trucks10%
Lanes on structure2
Traffic directionOne-way traffic
CarriesHighway
CrossesWaterway
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 proposedDeck replacement with only incidental widening
Estimated improvement cost—
NavigationNo navigation control on waterway

Frequently asked questions

When was I-75 NB over Pine River built?

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

What condition is I-75 NB over Pine 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 December 2024.

How much traffic does I-75 NB over Pine River carry?

About 1,508 vehicles per day (2007 count), of which roughly 10% are trucks.

How long is I-75 NB over Pine River?

The structure is 521 ft (158.8 m) long with a longest span of 58 ft (17.7 m) and a deck 36 ft wide.

Who owns I-75 NB over Pine River?

It is owned by the State Highway Agency.