US Bridges

I-75 NB over E Br Au Sable River

Fair

Crawford County, Michigan · 2.4 MI N of M-72 · Structure no. 000000000002041

Built
1961
64 years old
Condition
Fair
inspected May 2024
Type
Stringer/Multi-beam or Girder
Steel
Length
39 ft
1 main span
Daily traffic
9,772
2022 count
Owner
State
State Highway Agency

About this bridge

I-75 NB over E Br Au Sable River is a steel stringer/multi-beam or girder carrying I-75 NB over E Br Au Sable River in Crawford County, Michigan. It was built in 1961, so it is 64 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 5 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 9,772 vehicles a day, roughly 11% of them trucks. The structure is 39 ft (11.9 m) long and 47 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

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CarriesI-75 NB
CrossesE Br Au Sable River
Location2.4 MI N of M-72
RouteInterstate 75
CountyCrawford County
StateMichigan
Coordinates44.69151, -84.69746
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
Deck5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Superstructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection8 Very GoodNo problems noted.
Last inspectionMay 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourScour critical; foundations unstable for calculated scour conditions
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Deck geometry8: Equal to present desirable criteria
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment7: Better than present minimum criteria
Operating rating72.1 US tons
Inventory rating43.2 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel
DeckConcrete, cast-in-place
Main spans1
Design loadHS 20 + Mod
Structure length39 ft (11.9 m)
Longest span37 ft (11.4 m)
Deck width47 ft (14.4 m)
Roadway width42 ft (12.8 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic9,772 (2022)
Projected traffic—
Trucks11%
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 proposedNone recorded
Estimated improvement cost—
NavigationNo navigation control on waterway

Frequently asked questions

When was I-75 NB over E Br Au Sable River built?

It was built in 1961, making it 64 years old in 2025.

What condition is I-75 NB over E Br Au Sable 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 I-75 NB over E Br Au Sable River carry?

About 9,772 vehicles per day (2022 count), of which roughly 11% are trucks.

How long is I-75 NB over E Br Au Sable River?

The structure is 39 ft (11.9 m) long with a longest span of 37 ft (11.4 m) and a deck 47 ft wide.

Who owns I-75 NB over E Br Au Sable River?

It is owned by the State Highway Agency.