US Bridges

N Union RD over I-75

Fair

Bay County, Michigan · 3.0 MI S of Kawkawlin · Structure no. 000000000000628

Built
1961
64 years old, rebuilt 2001
Condition
Fair
inspected December 2024
Type
Stringer/Multi-beam or Girder
Steel
Length
208 ft
4 main spans
Daily traffic
1,045
1995 count
Owner
State
State Highway Agency

About this bridge

N Union RD over I-75 is a steel stringer/multi-beam or girder carrying N Union RD over I-75 in Bay County, Michigan. It was built in 1961 and reconstructed in 2001, so it is 64 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 1,045 vehicles a day, roughly 3% of them trucks, projected to reach 450 by 1977. The structure is 208 ft (63.4 m) long and 31 ft wide. If it were closed, the detour would be 1.9 mi (3 km).

Location

Open in Google Maps
CarriesN Union RD
CrossesI-75
Location3.0 MI S of Kawkawlin
RouteCounty Highway 0
CountyBay County
StateMichigan
Coordinates43.60941, -83.94762
Functional classUrban 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.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionDecember 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourBridge not over waterway
Structural evaluation6: Equal to present minimum criteria
Deck geometry4: Meets minimum tolerable limits to be left in place as is
Approach roadway alignment5: Somewhat better than minimum adequacy to tolerate being left in place as is
Operating rating67.5 US tons
Inventory rating35.1 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel
DeckConcrete, cast-in-place
Main spans4
Design loadH 15
Structure length208 ft (63.4 m)
Longest span71 ft (21.6 m)
Deck width31 ft (9.5 m)
Roadway width24 ft (7.3 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic1,045 (1995)
Projected traffic450 by 1977
Trucks3%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesHighway
Detour if closed1.9 mi (3 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 proposedReplacement because of substandard load-carrying capacity or roadway geometry
Estimated improvement cost$72,000
NavigationNot applicable (no waterway)

Frequently asked questions

When was N Union RD over I-75 built?

It was built in 1961, making it 64 years old in 2025. It was reconstructed in 2001.

What condition is N Union RD over I-75 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 December 2024.

How much traffic does N Union RD over I-75 carry?

About 1,045 vehicles per day (1995 count), of which roughly 3% are trucks.

How long is N Union RD over I-75?

The structure is 208 ft (63.4 m) long with a longest span of 71 ft (21.6 m) and a deck 31 ft wide.

Who owns N Union RD over I-75?

It is owned by the State Highway Agency.