US Bridges

M-21 Br over Plaster Creek

Fair

Kent County, Michigan · In Wyoming · Structure no. 000000000004853

Built
1916
109 years old
Condition
Fair
inspected August 2024
Type
Arch - Deck
Concrete
Length
60 ft
1 main span
Daily traffic
16,531
2007 count
Owner
State
State Highway Agency

About this bridge

M-21 Br over Plaster Creek is a concrete arch - deck carrying M-21 Br over Plaster Creek in Kent County, Michigan. It was built in 1916, so it is 109 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 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 16,531 vehicles a day, roughly 10% of them trucks, projected to reach 18,421 by 2018. The structure is 60 ft (18.2 m) long and 66 ft wide. If it were closed, the detour would be 3.7 mi (6 km).

Location

Open in Google Maps
CarriesM-21 Br
CrossesPlaster Creek
LocationIn Wyoming
RouteState Highway 21
CountyKent County
StateMichigan
Coordinates42.93582, -85.68759
Functional classUrban Other Principal Arterial

Condition and inspection

Fair

The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.

ComponentRatingMeaning
Deck5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Superstructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection7 GoodSome minor problems.
Last inspectionAugust 2024
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 geometry4: Meets minimum tolerable limits to be left in place as is
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment7: Better than present minimum criteria
Operating rating98.5 US tons
Inventory rating59 US tons

Structure

Structure typeArch - Deck
MaterialConcrete
DeckNot applicable
Main spans1
Design loadH 20
Structure length60 ft (18.2 m)
Longest span60 ft (18.2 m)
Deck width66 ft (20.1 m)
Roadway width42 ft (12.8 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic16,531 (2007)
Projected traffic18,421 by 2018
Trucks10%
Lanes on structure3
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed3.7 mi (6 km)
TollOn a free road
National Highway SystemYes

Ownership and planned work

OwnerState Highway Agency
Maintained byState Highway Agency
Historic statusListed on the National Register of Historic Places
Work proposedNone recorded
Estimated improvement cost—
NavigationNo navigation control on waterway

Frequently asked questions

When was M-21 Br over Plaster Creek built?

It was built in 1916, making it 109 years old in 2025.

What condition is M-21 Br over Plaster Creek 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 August 2024.

How much traffic does M-21 Br over Plaster Creek carry?

About 16,531 vehicles per day (2007 count), of which roughly 10% are trucks.

How long is M-21 Br over Plaster Creek?

The structure is 60 ft (18.2 m) long with a longest span of 60 ft (18.2 m) and a deck 66 ft wide.

Who owns M-21 Br over Plaster Creek?

It is owned by the State Highway Agency.