US Bridges

M-57 over Flint River

Fair

Genesee County, Michigan · 1.0 MI E of Montrose · Structure no. 000000000002618

Built
1926
99 years old, rebuilt 1992
Condition
Fair
inspected August 2023
Type
Stringer/Multi-beam or Girder
Prestressed Concrete
Length
351 ft
5 main spans
Daily traffic
9,126
2020 count
Owner
State
State Highway Agency

About this bridge

M-57 over Flint River is a prestressed concrete stringer/multi-beam or girder carrying M-57 over Flint River in Genesee County, Michigan. It was built in 1926 and reconstructed in 1992, so it is 99 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 6 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 9,126 vehicles a day, roughly 5% of them trucks, projected to reach 10,495 by 2040. The structure is 351 ft (107.1 m) long and 47 ft wide. If it were closed, the detour would be 8.7 mi (14 km).

Location

Open in Google Maps
CarriesM-57
CrossesFlint River
Location1.0 MI E of Montrose
RouteState Highway 57
CountyGenesee County
StateMichigan
Coordinates43.17624, -83.87779
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
Deck9 ExcellentNo problems noted.
Superstructure7 GoodSome minor problems.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Last inspectionAugust 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourScour critical; foundations unstable for calculated scour conditions
Structural evaluation6: Equal to 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 rating80 US tons
Inventory rating44.6 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans5
Design loadH 15
Structure length351 ft (107.1 m)
Longest span70 ft (21.3 m)
Deck width47 ft (14.4 m)
Roadway width44 ft (13.4 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic9,126 (2020)
Projected traffic10,495 by 2040
Trucks5%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed8.7 mi (14 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-57 over Flint River built?

It was built in 1926, making it 99 years old in 2025. It was reconstructed in 1992.

What condition is M-57 over Flint 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-57 over Flint River carry?

About 9,126 vehicles per day (2020 count), of which roughly 5% are trucks.

How long is M-57 over Flint River?

The structure is 351 ft (107.1 m) long with a longest span of 70 ft (21.3 m) and a deck 47 ft wide.

Who owns M-57 over Flint River?

It is owned by the State Highway Agency.