US Bridges

County Road Extn over Black River

Good

Marquette County, Michigan · 0.5 MI W of CR 581 · Structure no. 000000000013722

Built
2021
4 years old
Condition
Good
inspected October 2023
Type
Stringer/Multi-beam or Girder
Steel
Length
55 ft
1 main span
Daily traffic
10
2013 count
Owner
State
Other State Agency

About this bridge

County Road Extn over Black River is a steel stringer/multi-beam or girder carrying County Road Extn over Black River in Marquette County, Michigan. It was built in 2021, so it is 4 years old, younger than the Michigan average of 48.3 years.

The most recent inspection reported to the Federal Highway Administration rates it in good condition with a lowest component rating of 7 out of 9. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

It carries about 10 vehicles a day, projected to reach 10 by 2033. The structure is 55 ft (16.8 m) long and 14 ft wide. If it were closed, the detour would be 198.8 mi (320 km).

Location

Open in Google Maps
CarriesCounty Road Extn
CrossesBlack River
Location0.5 MI W of CR 581
RouteState Lands Road 0
CountyMarquette County
StateMichigan
Coordinates46.4008, -87.843
Functional classRural Local

Condition and inspection

Good

All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

ComponentRatingMeaning
Deck8 Very GoodNo problems noted.
Superstructure8 Very GoodNo problems noted.
Substructure7 GoodSome minor problems.
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionOctober 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourCountermeasures installed to correct a previously existing problem
Structural evaluation7: Better than present minimum criteria
Deck geometry6: Equal to present minimum criteria
Waterway adequacy5: Somewhat better than minimum adequacy to tolerate being left in place as is
Approach roadway alignment5: Somewhat better than minimum adequacy to tolerate being left in place as is
Operating rating42.1 US tons
Inventory rating32.5 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel
DeckWood or timber
Main spans1
Design loadUnknown
Structure length55 ft (16.8 m)
Longest span49 ft (14.9 m)
Deck width14 ft (4.3 m)
Roadway width14 ft (4.3 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic10 (2013)
Projected traffic10 by 2033
Trucks0%
Lanes on structure1
Traffic directionOne-lane bridge for two-way traffic
CarriesHighway
CrossesWaterway
Detour if closed198.8 mi (320 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerOther State Agency
Maintained byOther State 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 County Road Extn over Black River built?

It was built in 2021, making it 4 years old in 2025.

What condition is County Road Extn over Black River in?

The National Bridge Inventory rates it in good condition. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted. The last reported inspection was in October 2023.

How much traffic does County Road Extn over Black River carry?

About 10 vehicles per day (2013 count).

How long is County Road Extn over Black River?

The structure is 55 ft (16.8 m) long with a longest span of 49 ft (14.9 m) and a deck 14 ft wide.

Who owns County Road Extn over Black River?

It is owned by the Other State Agency.