US Bridges

M-20 (eight MI Rd) over Muskegon River

Fair

Mecosta County, Michigan · 4 MI W of Stanwood · Structure no. 000000000006759

Built
1977
48 years old
Condition
Fair
inspected October 2023
Type
Stringer/Multi-beam or Girder
Steel
Length
283 ft
4 main spans
Daily traffic
3,615
2007 count
Owner
State
State Highway Agency

About this bridge

M-20 (eight MI Rd) over Muskegon River is a steel stringer/multi-beam or girder carrying M-20 (eight MI Rd) over Muskegon River in Mecosta 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 5 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 3,615 vehicles a day, roughly 12% of them trucks, projected to reach 4,221 by 2018. The structure is 283 ft (86.3 m) long and 40 ft wide. If it were closed, the detour would be 8.7 mi (14 km).

Location

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CarriesM-20 (eight MI Rd)
CrossesMuskegon River
Location4 MI W of Stanwood
RouteState Highway 20
CountyMecosta County
StateMichigan
Coordinates43.58393, -85.52589
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.
Superstructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Substructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Channel and channel protection8 Very GoodNo problems noted.
Last inspectionOctober 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourScour critical; foundations unstable for calculated scour conditions
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Deck geometry5: Somewhat better than minimum adequacy to tolerate being left in place as is
Waterway adequacy9: Superior to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating72.9 US tons
Inventory rating43.5 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel
DeckConcrete, cast-in-place
Main spans4
Design loadHS 20 + Mod
Structure length283 ft (86.3 m)
Longest span71 ft (21.6 m)
Deck width40 ft (12.2 m)
Roadway width37 ft (11.4 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic3,615 (2007)
Projected traffic4,221 by 2018
Trucks12%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed8.7 mi (14 km)
TollOn a free road
National Highway SystemNo

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-20 (eight MI Rd) over Muskegon River built?

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

What condition is M-20 (eight MI Rd) over Muskegon 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 October 2023.

How much traffic does M-20 (eight MI Rd) over Muskegon River carry?

About 3,615 vehicles per day (2007 count), of which roughly 12% are trucks.

How long is M-20 (eight MI Rd) over Muskegon River?

The structure is 283 ft (86.3 m) long with a longest span of 71 ft (21.6 m) and a deck 40 ft wide.

Who owns M-20 (eight MI Rd) over Muskegon River?

It is owned by the State Highway Agency.