US Bridges

Mosinee Grade Road over Black River

FairPosted for load

Gogebic County, Michigan · Sec 28 Erwin Twp · Structure no. 000000000003005

Built
1958
67 years old, rebuilt 2003
Condition
Fair
inspected September 2024
Type
Stringer/Multi-beam or Girder
Steel
Length
50 ft
1 main span
Daily traffic
10
1998 count
Owner
County
County Highway Agency

About this bridge

Mosinee Grade Road over Black River is a steel stringer/multi-beam or girder carrying Mosinee Grade Road over Black River in Gogebic County, Michigan. It was built in 1958 and reconstructed in 2003, so it is 67 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. Its operating status is: posted for load restriction.

It carries about 10 vehicles a day, projected to reach 10 by 2018. The structure is 50 ft (15.2 m) long and 21 ft wide. If it were closed, the detour would be 29.8 mi (48 km).

Location

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CarriesMosinee Grade Road
CrossesBlack River
LocationSec 28 Erwin Twp
RouteCounty Highway 0
CountyGogebic County
StateMichigan
Coordinates46.35886, -90.06104
Functional classRural Local

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 protection7 GoodSome minor problems.
Last inspectionSeptember 2024
Inspection intervalevery 24 months
Operating statusPosted for load restriction
ScourUnknown foundation; not evaluated for scour
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Deck geometry5: Somewhat better than minimum adequacy to tolerate being left in place as is
Waterway adequacy6: Equal to present minimum criteria
Approach roadway alignment7: Better than present minimum criteria
Operating rating34.3 US tons
Inventory rating18.2 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel
DeckWood or timber
Main spans1
Design loadHS 20
Structure length50 ft (15.2 m)
Longest span38 ft (11.6 m)
Deck width21 ft (6.4 m)
Roadway width20 ft (6.1 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic10 (1998)
Projected traffic10 by 2018
Trucks0%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed29.8 mi (48 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerCounty Highway Agency
Maintained byCounty 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$265,000
NavigationNo navigation control on waterway

Frequently asked questions

When was Mosinee Grade Road over Black River built?

It was built in 1958, making it 67 years old in 2025. It was reconstructed in 2003.

What condition is Mosinee Grade Road over Black 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 September 2024.

How much traffic does Mosinee Grade Road over Black River carry?

About 10 vehicles per day (1998 count).

How long is Mosinee Grade Road over Black River?

The structure is 50 ft (15.2 m) long with a longest span of 38 ft (11.6 m) and a deck 21 ft wide.

Who owns Mosinee Grade Road over Black River?

It is owned by the County Highway Agency.