US Bridges

Cochran Road over Thornapple River

Fair

Eaton County, Michigan · 6 MI N of Charlotte · Structure no. 000000000002354

Built
1960
65 years old
Condition
Fair
inspected May 2023
Type
Box Beam or Girders - Multiple
Prestressed Concrete
Length
50 ft
1 main span
Daily traffic
1,150
2011 count
Owner
County
County Highway Agency

About this bridge

Cochran Road over Thornapple River is a prestressed concrete box beam or girders - multiple carrying Cochran Road over Thornapple River in Eaton County, Michigan. It was built in 1960, so it is 65 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 6 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 1,150 vehicles a day, projected to reach 2,200 by 2013. The structure is 50 ft (15.2 m) long and 27 ft wide. If it were closed, the detour would be 3.7 mi (6 km).

Location

Open in Google Maps
CarriesCochran Road
CrossesThornapple River
Location6 MI N of Charlotte
RouteCounty Highway 2351
CountyEaton County
StateMichigan
Coordinates42.66118, -84.83695
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
Deck7 GoodSome minor problems.
Superstructure7 GoodSome minor problems.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionMay 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourScour critical; foundations unstable for calculated scour conditions
Structural evaluation6: Equal to present minimum criteria
Deck geometry4: Meets minimum tolerable limits to be left in place as is
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating43.2 US tons
Inventory rating31.7 US tons

Structure

Structure typeBox Beam or Girders - Multiple
MaterialPrestressed Concrete
DeckConcrete, precast panels
Main spans1
Design loadH 20
Structure length50 ft (15.2 m)
Longest span49 ft (14.9 m)
Deck width27 ft (8.2 m)
Roadway width26 ft (7.9 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic1,150 (2011)
Projected traffic2,200 by 2013
Trucks0%
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 proposedRehabilitation because of general structure deterioration or inadequate strength
Estimated improvement cost$30,000
NavigationNo navigation control on waterway

Frequently asked questions

When was Cochran Road over Thornapple River built?

It was built in 1960, making it 65 years old in 2025.

What condition is Cochran Road over Thornapple 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 May 2023.

How much traffic does Cochran Road over Thornapple River carry?

About 1,150 vehicles per day (2011 count).

How long is Cochran Road over Thornapple River?

The structure is 50 ft (15.2 m) long with a longest span of 49 ft (14.9 m) and a deck 27 ft wide.

Who owns Cochran Road over Thornapple River?

It is owned by the County Highway Agency.