US Bridges

Michigan Avenue over Portage River

Fair

St. Joseph County, Michigan · South of Portage Lake · Structure no. 000000000010299

Built
1964
61 years old
Condition
Fair
inspected November 2023
Type
Box Beam or Girders - Multiple
Prestressed Concrete
Length
68 ft
2 main spans
Daily traffic
842
2019 count
Owner
County
County Highway Agency

About this bridge

Michigan Avenue over Portage River is a prestressed concrete box beam or girders - multiple carrying Michigan Avenue over Portage River in St. Joseph County, Michigan. It was built in 1964, so it is 61 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 842 vehicles a day, roughly 7% of them trucks, projected to reach 894 by 2049. The structure is 68 ft (20.7 m) long and 30 ft wide. If it were closed, the detour would be 3.7 mi (6 km).

Location

Open in Google Maps
CarriesMichigan Avenue
CrossesPortage River
LocationSouth of Portage Lake
RouteCounty Highway 7892
CountySt. Joseph County
StateMichigan
Coordinates42.03886, -85.51543
Functional classRural Major Collector

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.
Superstructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Substructure7 GoodSome minor problems.
Channel and channel protection8 Very GoodNo problems noted.
Last inspectionNovember 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 geometry6: Equal to present minimum criteria
Waterway adequacy7: Better than present minimum criteria
Approach roadway alignment7: Better than present minimum criteria
Operating rating71.1 US tons
Inventory rating42.5 US tons

Structure

Structure typeBox Beam or Girders - Multiple
MaterialPrestressed Concrete
DeckOther
Main spans2
Design loadHS 20
Structure length68 ft (20.7 m)
Longest span34 ft (10.3 m)
Deck width30 ft (9.2 m)
Roadway width30 ft (9.1 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic842 (2019)
Projected traffic894 by 2049
Trucks7%
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

OwnerCounty Highway Agency
Maintained byCounty 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 Michigan Avenue over Portage River built?

It was built in 1964, making it 61 years old in 2025.

What condition is Michigan Avenue over Portage 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 November 2023.

How much traffic does Michigan Avenue over Portage River carry?

About 842 vehicles per day (2019 count), of which roughly 7% are trucks.

How long is Michigan Avenue over Portage River?

The structure is 68 ft (20.7 m) long with a longest span of 34 ft (10.3 m) and a deck 30 ft wide.

Who owns Michigan Avenue over Portage River?

It is owned by the County Highway Agency.