US Bridges

M-6 WB over Thornapple River Drive

Fair

Kent County, Michigan · Cascade Twp Sec 33 · Structure no. 000000000012817

Built
1999
26 years old
Condition
Fair
inspected May 2023
Type
Stringer/Multi-beam or Girder
Prestressed Concrete
Length
252 ft
3 main spans
Daily traffic
13,761
2007 count
Owner
State
State Highway Agency

About this bridge

M-6 WB over Thornapple River Drive is a prestressed concrete stringer/multi-beam or girder carrying M-6 WB over Thornapple River Drive in Kent County, Michigan. It was built in 1999, so it is 26 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.

It carries about 13,761 vehicles a day, roughly 8% of them trucks, projected to reach 14,900 by 2015. The structure is 252 ft (76.9 m) long and 47 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

Open in Google Maps
CarriesM-6 WB
CrossesThornapple River Drive
LocationCascade Twp Sec 33
RouteState Highway 6
CountyKent County
StateMichigan
Coordinates42.86621, -85.49836
Functional classUrban Principal Arterial - Other Freeway or Expressway

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.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure7 GoodSome minor problems.
Last inspectionMay 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourBridge not over waterway
Structural evaluation6: Equal to present minimum criteria
Deck geometry9: Superior to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating92.5 US tons
Inventory rating48.2 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans3
Design loadHS 25 or greater
Structure length252 ft (76.9 m)
Longest span133 ft (40.6 m)
Deck width47 ft (14.2 m)
Roadway width43 ft (13.2 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic13,761 (2007)
Projected traffic14,900 by 2015
Trucks8%
Lanes on structure2
Traffic directionOne-way traffic
CarriesHighway
CrossesHighway
Detour if closed1.2 mi (2 km)
TollOn a free road
National Highway SystemYes

Ownership and planned work

OwnerState Highway Agency
Maintained byState Highway Agency
Historic statusNot eligible for the National Register of Historic Places
Work proposedNone recorded
Estimated improvement cost—
NavigationNot applicable (no waterway)

Frequently asked questions

When was M-6 WB over Thornapple River Drive built?

It was built in 1999, making it 26 years old in 2025.

What condition is M-6 WB over Thornapple River Drive 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 M-6 WB over Thornapple River Drive carry?

About 13,761 vehicles per day (2007 count), of which roughly 8% are trucks.

How long is M-6 WB over Thornapple River Drive?

The structure is 252 ft (76.9 m) long with a longest span of 133 ft (40.6 m) and a deck 47 ft wide.

Who owns M-6 WB over Thornapple River Drive?

It is owned by the State Highway Agency.