US Bridges

M-15 over Flint River

Fair

Genesee County, Michigan · 1.2 MI N of Richfield Cen · Structure no. 000000000002613

Built
1928
97 years old, rebuilt 1978
Condition
Fair
inspected August 2023
Type
Stringer/Multi-beam or Girder
Steel
Length
110 ft
2 main spans
Daily traffic
8,725
2013 count
Owner
State
State Highway Agency

About this bridge

M-15 over Flint River is a steel stringer/multi-beam or girder carrying M-15 over Flint River in Genesee County, Michigan. It was built in 1928 and reconstructed in 1978, so it is 97 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 8,725 vehicles a day, roughly 9% of them trucks, projected to reach 9,625 by 2033. The structure is 110 ft (33.5 m) long and 43 ft wide. If it were closed, the detour would be 3.7 mi (6 km).

Location

Open in Google Maps
CarriesM-15
CrossesFlint River
Location1.2 MI N of Richfield Cen
RouteState Highway 15
CountyGenesee County
StateMichigan
Coordinates43.11116, -83.51885
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 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 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 adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating60.7 US tons
Inventory rating36.4 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel
DeckConcrete, cast-in-place
Main spans2
Design loadHS 20
Structure length110 ft (33.5 m)
Longest span55 ft (16.7 m)
Deck width43 ft (13 m)
Roadway width39 ft (11.8 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic8,725 (2013)
Projected traffic9,625 by 2033
Trucks9%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed3.7 mi (6 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-15 over Flint River built?

It was built in 1928, making it 97 years old in 2025. It was reconstructed in 1978.

What condition is M-15 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-15 over Flint River carry?

About 8,725 vehicles per day (2013 count), of which roughly 9% are trucks.

How long is M-15 over Flint River?

The structure is 110 ft (33.5 m) long with a longest span of 55 ft (16.7 m) and a deck 43 ft wide.

Who owns M-15 over Flint River?

It is owned by the State Highway Agency.