US Bridges

Marine City HWY over Unnamed Creek

Good

St. Clair County, Michigan · Sec 34 Casco Twp · Structure no. 000000000010035

Built
1946
79 years old, rebuilt 2017
Condition
Good
inspected October 2023
Type
Stringer/Multi-beam or Girder
Steel
Length
25 ft
1 main span
Daily traffic
11,741
2015 count
Owner
County
County Highway Agency

About this bridge

Marine City HWY over Unnamed Creek is a steel stringer/multi-beam or girder carrying Marine City HWY over Unnamed Creek in St. Clair County, Michigan. It was built in 1946 and reconstructed in 2017, so it is 79 years old, older than the Michigan average of 48.3 years.

The most recent inspection reported to the Federal Highway Administration rates it in good condition with a lowest component rating of 7 out of 9. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

It carries about 11,741 vehicles a day, roughly 9% of them trucks, projected to reach 17,446 by 2035. The structure is 25 ft (7.6 m) long and 41 ft wide. If it were closed, the detour would be 1.9 mi (3 km).

Location

Open in Google Maps
CarriesMarine City HWY
CrossesUnnamed Creek
LocationSec 34 Casco Twp
RouteCounty Highway 7728
CountySt. Clair County
StateMichigan
Coordinates42.72314, -82.66714
Functional classRural Major Collector

Condition and inspection

Good

All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

ComponentRatingMeaning
Deck7 GoodSome minor problems.
Superstructure8 Very GoodNo problems noted.
Substructure7 GoodSome minor problems.
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionOctober 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour within limits of footing or piles
Structural evaluation7: Better than present minimum criteria
Deck geometry5: Somewhat better than minimum adequacy to tolerate being left in place as is
Waterway adequacy6: Equal to present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating79.7 US tons
Inventory rating61.4 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel
DeckConcrete, precast panels
Main spans1
Design loadGreater than HL 93
Structure length25 ft (7.6 m)
Longest span23 ft (6.9 m)
Deck width41 ft (12.6 m)
Roadway width38 ft (11.7 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic11,741 (2015)
Projected traffic17,446 by 2035
Trucks9%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed1.9 mi (3 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 proposedReplacement because of substandard load-carrying capacity or roadway geometry
Estimated improvement cost$130,000
NavigationNo navigation control on waterway

Frequently asked questions

When was Marine City HWY over Unnamed Creek built?

It was built in 1946, making it 79 years old in 2025. It was reconstructed in 2017.

What condition is Marine City HWY over Unnamed Creek in?

The National Bridge Inventory rates it in good condition. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted. The last reported inspection was in October 2023.

How much traffic does Marine City HWY over Unnamed Creek carry?

About 11,741 vehicles per day (2015 count), of which roughly 9% are trucks.

How long is Marine City HWY over Unnamed Creek?

The structure is 25 ft (7.6 m) long with a longest span of 23 ft (6.9 m) and a deck 41 ft wide.

Who owns Marine City HWY over Unnamed Creek?

It is owned by the County Highway Agency.