US Bridges

M-6(RMP B to I-96) over Thornapple River

Good

Kent County, Michigan · Cascade Twp Sec 22 · Structure no. 000000000012737

Built
1997
28 years old
Condition
Good
inspected November 2024
Type
Stringer/Multi-beam or Girder
Steel Continuous
Length
1,086 ft
6 main spans
Daily traffic
11,738
2023 count
Owner
State
State Highway Agency

About this bridge

M-6(RMP B to I-96) over Thornapple River is a steel continuous stringer/multi-beam or girder carrying M-6(RMP B to I-96) over Thornapple River in Kent County, Michigan. It was built in 1997, so it is 28 years old, younger 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 11,738 vehicles a day, roughly 13% of them trucks. The structure is 1,086 ft (330.9 m) long and 47 ft wide.

Location

Open in Google Maps
CarriesM-6(RMP B to I-96)
CrossesThornapple River
LocationCascade Twp Sec 22
RouteState Highway 6
CountyKent County
StateMichigan
Coordinates42.88783, -85.48598
Functional classUrban Principal Arterial - Other Freeway or Expressway

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.
Superstructure7 GoodSome minor problems.
Substructure7 GoodSome minor problems.
Channel and channel protection8 Very GoodNo problems noted.
Last inspectionNovember 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation7: Better than present minimum criteria
Deck geometry9: Superior to present desirable criteria
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating91.8 US tons
Inventory rating55 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel Continuous
DeckConcrete, cast-in-place
Main spans6
Design loadHS 25 or greater
Structure length1,086 ft (330.9 m)
Longest span182 ft (55.4 m)
Deck width47 ft (14.2 m)
Roadway width43 ft (13.2 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic11,738 (2023)
Projected traffic—
Trucks13%
Lanes on structure2
Traffic directionOne-way traffic
CarriesHighway
CrossesWaterway
Detour if closed—
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—
NavigationNo navigation control on waterway

Frequently asked questions

When was M-6(RMP B to I-96) over Thornapple River built?

It was built in 1997, making it 28 years old in 2025.

What condition is M-6(RMP B to I-96) over Thornapple River 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 November 2024.

How much traffic does M-6(RMP B to I-96) over Thornapple River carry?

About 11,738 vehicles per day (2023 count), of which roughly 13% are trucks.

How long is M-6(RMP B to I-96) over Thornapple River?

The structure is 1,086 ft (330.9 m) long with a longest span of 182 ft (55.4 m) and a deck 47 ft wide.

Who owns M-6(RMP B to I-96) over Thornapple River?

It is owned by the State Highway Agency.