US Bridges

M-77 over Manistique River

Fair

Schoolcraft County, Michigan · 9.1 MI N of US-2 · Structure no. 000000000009684

Built
1954
71 years old
Condition
Fair
inspected September 2023
Type
Stringer/Multi-beam or Girder
Steel
Length
179 ft
3 main spans
Daily traffic
1,490
2007 count
Owner
State
State Highway Agency

About this bridge

M-77 over Manistique River is a steel stringer/multi-beam or girder carrying M-77 over Manistique River in Schoolcraft County, Michigan. It was built in 1954, so it is 71 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 1,490 vehicles a day, roughly 10% of them trucks, projected to reach 1,631 by 2018. The structure is 179 ft (54.6 m) long and 33 ft wide. If it were closed, the detour would be 24.2 mi (39 km).

Location

Open in Google Maps
CarriesM-77
CrossesManistique River
Location9.1 MI N of US-2
RouteState Highway 77
CountySchoolcraft County
StateMichigan
Coordinates46.23196, -85.92887
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.
Substructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionSeptember 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour within limits of footing or piles
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 adequacy7: Better than present minimum criteria
Approach roadway alignment7: Better than present minimum criteria
Operating rating68.2 US tons
Inventory rating40.7 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel
DeckConcrete, cast-in-place
Main spans3
Design loadHS 20
Structure length179 ft (54.6 m)
Longest span59 ft (18.1 m)
Deck width33 ft (10.2 m)
Roadway width30 ft (9.2 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic1,490 (2007)
Projected traffic1,631 by 2018
Trucks10%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed24.2 mi (39 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—
NavigationNo navigation control on waterway

Frequently asked questions

When was M-77 over Manistique River built?

It was built in 1954, making it 71 years old in 2025.

What condition is M-77 over Manistique 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 2023.

How much traffic does M-77 over Manistique River carry?

About 1,490 vehicles per day (2007 count), of which roughly 10% are trucks.

How long is M-77 over Manistique River?

The structure is 179 ft (54.6 m) long with a longest span of 59 ft (18.1 m) and a deck 33 ft wide.

Who owns M-77 over Manistique River?

It is owned by the State Highway Agency.