US Bridges

68th Street over Thornapple River

Fair

Kent County, Michigan · 0.10 MI E of Thornapple R · Structure no. 000000000005015

Built
1967
58 years old
Condition
Fair
inspected November 2023
Type
Stringer/Multi-beam or Girder
Prestressed Concrete
Length
234 ft
3 main spans
Daily traffic
6,293
2018 count
Owner
County
County Highway Agency

About this bridge

68th Street over Thornapple River is a prestressed concrete stringer/multi-beam or girder carrying 68th Street over Thornapple River in Kent County, Michigan. It was built in 1967, so it is 58 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 6,293 vehicles a day, roughly 8% of them trucks, projected to reach 8,500 by 2038. The structure is 234 ft (71.3 m) long and 37 ft wide. If it were closed, the detour would be 5 mi (8 km).

Carries68th Street
CrossesThornapple River
Location0.10 MI E of Thornapple R
RouteCounty Highway 4116
Coordinates42.83998, -85.47709
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.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection7 GoodSome minor problems.
Last inspectionNovember 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 rating110.1 US tons
Inventory rating64.8 US tons

Structure

MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans3
Design loadHS 20 + Mod
Structure length234 ft (71.3 m)
Longest span78 ft (23.8 m)
Deck width37 ft (11.4 m)
Roadway width30 ft (9.1 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic6,293 (2018)
Projected traffic8,500 by 2038
Trucks8%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed5 mi (8 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$137,000
NavigationNo navigation control on waterway

Frequently asked questions

When was 68th Street over Thornapple River built?

It was built in 1967, making it 58 years old in 2025.

What condition is 68th Street 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 November 2023.

How much traffic does 68th Street over Thornapple River carry?

About 6,293 vehicles per day (2018 count), of which roughly 8% are trucks.

How long is 68th Street over Thornapple River?

The structure is 234 ft (71.3 m) long with a longest span of 78 ft (23.8 m) and a deck 37 ft wide.

Who owns 68th Street over Thornapple River?

It is owned by the County Highway Agency.