US Bridges

M-29 over Belle River

Fair

St. Clair County, Michigan · In Marine City · Structure no. 000000000009976

Built
1938
87 years old, rebuilt 1981
Condition
Fair
inspected March 2023
Type
Stringer/Multi-beam or Girder
Steel Continuous
Length
94 ft
3 main spans
Daily traffic
7,474
2007 count
Owner
State
State Highway Agency

About this bridge

M-29 over Belle River is a steel continuous stringer/multi-beam or girder carrying M-29 over Belle River in St. Clair County, Michigan. It was built in 1938 and reconstructed in 1981, so it is 87 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 7,474 vehicles a day, roughly 2% of them trucks, projected to reach 8,662 by 2018. The structure is 94 ft (28.6 m) long and 40 ft wide. If it were closed, the detour would be 3.1 mi (5 km).

Location

Open in Google Maps
CarriesM-29
CrossesBelle River
LocationIn Marine City
RouteState Highway 29
CountySt. Clair County
StateMichigan
Coordinates42.72113, -82.49644
Functional classUrban 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.
Substructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Channel and channel protection7 GoodSome minor problems.
Last inspectionMarch 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Deck geometry3: Basically intolerable, requiring high priority of corrective action
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment6: Equal to present minimum criteria
Operating rating67.9 US tons
Inventory rating40.7 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel Continuous
DeckConcrete, cast-in-place
Main spans3
Design loadH 20
Structure length94 ft (28.6 m)
Longest span36 ft (10.9 m)
Deck width40 ft (12.3 m)
Roadway width30 ft (9.1 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic7,474 (2007)
Projected traffic8,662 by 2018
Trucks2%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed3.1 mi (5 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—
NavigationNavigation control on waterway (bridge permit required)

Frequently asked questions

When was M-29 over Belle River built?

It was built in 1938, making it 87 years old in 2025. It was reconstructed in 1981.

What condition is M-29 over Belle 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 March 2023.

How much traffic does M-29 over Belle River carry?

About 7,474 vehicles per day (2007 count), of which roughly 2% are trucks.

How long is M-29 over Belle River?

The structure is 94 ft (28.6 m) long with a longest span of 36 ft (10.9 m) and a deck 40 ft wide.

Who owns M-29 over Belle River?

It is owned by the State Highway Agency.