US Bridges

M-64 over Mineral River

Fair

Ontonagon County, Michigan · 1.0 MI NE of M-107 · Structure no. 000000000008468

Built
1941
84 years old
Condition
Fair
inspected August 2024
Type
Stringer/Multi-beam or Girder
Steel
Length
80 ft
2 main spans
Daily traffic
875
2013 count
Owner
State
State Highway Agency

About this bridge

M-64 over Mineral River is a steel stringer/multi-beam or girder carrying M-64 over Mineral River in Ontonagon County, Michigan. It was built in 1941, so it is 84 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 875 vehicles a day, roughly 11% of them trucks, projected to reach 1,025 by 2033. The structure is 80 ft (24.4 m) long and 38 ft wide. If it were closed, the detour would be 24.9 mi (40 km).

Location

Open in Google Maps
CarriesM-64
CrossesMineral River
Location1.0 MI NE of M-107
RouteState Highway 64
CountyOntonagon County
StateMichigan
Coordinates46.83409, -89.54942
Functional classRural Minor Arterial

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.
Superstructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Substructure7 GoodSome minor problems.
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionAugust 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourUnknown foundation; not evaluated for scour
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Deck geometry6: Equal to present minimum criteria
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment7: Better than present minimum criteria
Operating rating57.1 US tons
Inventory rating34.3 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel
DeckConcrete, cast-in-place
Main spans2
Design loadH 20
Structure length80 ft (24.4 m)
Longest span39 ft (11.8 m)
Deck width38 ft (11.7 m)
Roadway width33 ft (10.1 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic875 (2013)
Projected traffic1,025 by 2033
Trucks11%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed24.9 mi (40 km)
TollOn a free road
National Highway SystemNo

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$96,000
NavigationNo navigation control on waterway

Frequently asked questions

When was M-64 over Mineral River built?

It was built in 1941, making it 84 years old in 2025.

What condition is M-64 over Mineral 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 August 2024.

How much traffic does M-64 over Mineral River carry?

About 875 vehicles per day (2013 count), of which roughly 11% are trucks.

How long is M-64 over Mineral River?

The structure is 80 ft (24.4 m) long with a longest span of 39 ft (11.8 m) and a deck 38 ft wide.

Who owns M-64 over Mineral River?

It is owned by the State Highway Agency.