US Bridges

M-64 over Little Cranberry River

Fair

Ontonagon County, Michigan · 5.8 MI SW of US-45 · Structure no. 000000000008473

Built
1948
77 years old
Condition
Fair
inspected August 2023
Type
Stringer/Multi-beam or Girder
Steel
Length
79 ft
1 main span
Daily traffic
1,032
2007 count
Owner
State
State Highway Agency

About this bridge

M-64 over Little Cranberry River is a steel stringer/multi-beam or girder carrying M-64 over Little Cranberry River in Ontonagon County, Michigan. It was built in 1948, so it is 77 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 1,032 vehicles a day, roughly 11% of them trucks, projected to reach 1,149 by 2018. The structure is 79 ft (24.1 m) long and 33 ft wide. If it were closed, the detour would be 60.3 mi (97 km).

Location

Open in Google Maps
CarriesM-64
CrossesLittle Cranberry River
Location5.8 MI SW of US-45
RouteState Highway 64
CountyOntonagon County
StateMichigan
Coordinates46.83954, -89.43086
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
Deck5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Superstructure7 GoodSome minor problems.
Substructure7 GoodSome minor problems.
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionAugust 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourScour critical; foundations unstable for calculated scour conditions
Structural evaluation7: Better than present minimum criteria
Deck geometry5: Somewhat better than minimum adequacy to tolerate being left in place as is
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment7: Better than present minimum criteria
Operating rating95.3 US tons
Inventory rating57.1 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel
DeckConcrete, cast-in-place
Main spans1
Design loadHS 20
Structure length79 ft (24.1 m)
Longest span78 ft (23.9 m)
Deck width33 ft (10.2 m)
Roadway width28 ft (8.5 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic1,032 (2007)
Projected traffic1,149 by 2018
Trucks11%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed60.3 mi (97 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$39,000
NavigationNo navigation control on waterway

Frequently asked questions

When was M-64 over Little Cranberry River built?

It was built in 1948, making it 77 years old in 2025.

What condition is M-64 over Little Cranberry 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 2023.

How much traffic does M-64 over Little Cranberry River carry?

About 1,032 vehicles per day (2007 count), of which roughly 11% are trucks.

How long is M-64 over Little Cranberry River?

The structure is 79 ft (24.1 m) long with a longest span of 78 ft (23.9 m) and a deck 33 ft wide.

Who owns M-64 over Little Cranberry River?

It is owned by the State Highway Agency.