US Bridges

Trowbridge Road over Sturgeon River

FairPosted for load

Cheboygan County, Michigan · Sec 29 T33NR2W · Structure no. 000000000001539

Built
1977
48 years old
Condition
Fair
inspected July 2023
Type
Box Beam or Girders - Multiple
Prestressed Concrete
Length
44 ft
1 main span
Daily traffic
400
2005 count
Owner
County
County Highway Agency

About this bridge

Trowbridge Road over Sturgeon River is a prestressed concrete box beam or girders - multiple carrying Trowbridge Road over Sturgeon River in Cheboygan County, Michigan. It was built in 1977, so it is 48 years old, younger 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 6 out of 9. The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound. Its operating status is: posted for load restriction.

It carries about 400 vehicles a day, projected to reach 730 by 2025. The structure is 44 ft (13.4 m) long and 30 ft wide. If it were closed, the detour would be 39.8 mi (64 km).

Location

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CarriesTrowbridge Road
CrossesSturgeon River
LocationSec 29 T33NR2W
RouteCounty Highway 1631
CountyCheboygan County
StateMichigan
Coordinates45.22229, -84.58815
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
Deck6 SatisfactoryStructural elements show some minor deterioration.
Superstructure7 GoodSome minor problems.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionJuly 2023
Inspection intervalevery 24 months
Operating statusPosted for load restriction
ScourFoundations stable; scour within limits of footing or piles
Structural evaluation6: Equal to present minimum criteria
Deck geometry6: Equal to present minimum criteria
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating41.4 US tons
Inventory rating31.7 US tons

Structure

Structure typeBox Beam or Girders - Multiple
MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans1
Design loadHS 20 + Mod
Structure length44 ft (13.4 m)
Longest span40 ft (12.2 m)
Deck width30 ft (9.2 m)
Roadway width30 ft (9.1 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic400 (2005)
Projected traffic730 by 2025
Trucks0%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed39.8 mi (64 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 Trowbridge Road over Sturgeon River built?

It was built in 1977, making it 48 years old in 2025.

What condition is Trowbridge Road over Sturgeon 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 July 2023.

How much traffic does Trowbridge Road over Sturgeon River carry?

About 400 vehicles per day (2005 count).

How long is Trowbridge Road over Sturgeon River?

The structure is 44 ft (13.4 m) long with a longest span of 40 ft (12.2 m) and a deck 30 ft wide.

Who owns Trowbridge Road over Sturgeon River?

It is owned by the County Highway Agency.