US Bridges

M-64 over Floodwood River

Good

Ontonagon County, Michigan · 4.0 MI SW of US-45 · Structure no. 000000000008475

Built
1968
57 years old, rebuilt 2022
Condition
Good
inspected August 2023
Type
Stringer/Multi-beam or Girder
Steel Continuous
Length
81 ft
3 main spans
Daily traffic
1,725
2021 count
Owner
State
State Highway Agency

About this bridge

M-64 over Floodwood River is a steel continuous stringer/multi-beam or girder carrying M-64 over Floodwood River in Ontonagon County, Michigan. It was built in 1968 and reconstructed in 2022, so it is 57 years old, older 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 1,725 vehicles a day, roughly 3% of them trucks, projected to reach 2,000 by 2041. The structure is 81 ft (24.7 m) long and 46 ft wide. If it were closed, the detour would be 60.3 mi (97 km).

Location

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CarriesM-64
CrossesFloodwood River
Location4.0 MI SW of US-45
RouteState Highway 64
CountyOntonagon County
StateMichigan
Coordinates46.84822, -89.39579
Functional classRural Minor Arterial

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.
Superstructure7 GoodSome minor problems.
Substructure7 GoodSome minor problems.
Channel and channel protection7 GoodSome minor problems.
Last inspectionAugust 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour within limits of footing or piles
Structural evaluation7: Better than present minimum criteria
Deck geometry7: Better than present minimum criteria
Waterway adequacy6: Equal to present minimum criteria
Approach roadway alignment7: Better than present minimum criteria
Operating rating105.4 US tons
Inventory rating62.8 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel Continuous
DeckConcrete, cast-in-place
Main spans3
Design loadH 20
Structure length81 ft (24.7 m)
Longest span34 ft (10.4 m)
Deck width46 ft (14.1 m)
Roadway width43 ft (13.1 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic1,725 (2021)
Projected traffic2,000 by 2041
Trucks3%
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 proposedNone recorded
Estimated improvement cost—
NavigationNo navigation control on waterway

Frequently asked questions

When was M-64 over Floodwood River built?

It was built in 1968, making it 57 years old in 2025. It was reconstructed in 2022.

What condition is M-64 over Floodwood 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 August 2023.

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

About 1,725 vehicles per day (2021 count), of which roughly 3% are trucks.

How long is M-64 over Floodwood River?

The structure is 81 ft (24.7 m) long with a longest span of 34 ft (10.4 m) and a deck 46 ft wide.

Who owns M-64 over Floodwood River?

It is owned by the State Highway Agency.