US Bridges

I-275 NB over Conrail

Fair

Monroe County, Michigan · 1 MI NE of Carleton · Structure no. 000000000007210

Built
1973
52 years old
Condition
Fair
inspected July 2023
Type
Stringer/Multi-beam or Girder
Steel
Length
145 ft
3 main spans
Daily traffic
19,015
2007 count
Owner
State
State Highway Agency

About this bridge

I-275 NB over Conrail is a steel stringer/multi-beam or girder carrying I-275 NB over Conrail in Monroe County, Michigan. It was built in 1973, so it is 52 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 19,015 vehicles a day, roughly 19% of them trucks, projected to reach 17,579 by 2018. The structure is 145 ft (44.2 m) long and 56 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

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CarriesI-275 NB
CrossesConrail
Location1 MI NE of Carleton
RouteInterstate 275
CountyMonroe County
StateMichigan
Coordinates42.08106, -83.37356
Functional classRural Principal Arterial - Interstate

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.
Substructure7 GoodSome minor problems.
Last inspectionJuly 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourBridge not over waterway
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Deck geometry6: Equal to present minimum criteria
Approach roadway alignment6: Equal to present minimum criteria
Operating rating102.5 US tons
Inventory rating48.9 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel
DeckConcrete, cast-in-place
Main spans3
Design loadHS 20 + Mod
Structure length145 ft (44.2 m)
Longest span52 ft (15.8 m)
Deck width56 ft (17.2 m)
Roadway width53 ft (16.2 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic19,015 (2007)
Projected traffic17,579 by 2018
Trucks19%
Lanes on structure3
Traffic directionOne-way traffic
CarriesHighway
CrossesRailroad
Detour if closed1.2 mi (2 km)
TollOn a free road
National Highway SystemYes
Strategic Highway NetworkInterstate STRAHNET route

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—
NavigationNot applicable (no waterway)

Frequently asked questions

When was I-275 NB over Conrail built?

It was built in 1973, making it 52 years old in 2025.

What condition is I-275 NB over Conrail 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 July 2023.

How much traffic does I-275 NB over Conrail carry?

About 19,015 vehicles per day (2007 count), of which roughly 19% are trucks.

How long is I-275 NB over Conrail?

The structure is 145 ft (44.2 m) long with a longest span of 52 ft (15.8 m) and a deck 56 ft wide.

Who owns I-275 NB over Conrail?

It is owned by the State Highway Agency.