US Bridges

M-100 over Grand River

Fair

Eaton County, Michigan · In Grand Ledge · Structure no. 000000000002286

Built
1989
36 years old
Condition
Fair
inspected July 2023
Type
Stringer/Multi-beam or Girder
Prestressed Concrete
Length
534 ft
5 main spans
Daily traffic
13,838
2007 count
Owner
State
State Highway Agency

About this bridge

M-100 over Grand River is a prestressed concrete stringer/multi-beam or girder carrying M-100 over Grand River in Eaton County, Michigan. It was built in 1989, so it is 36 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 13,838 vehicles a day, roughly 4% of them trucks, projected to reach 15,073 by 2018. The structure is 534 ft (162.8 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-100
CrossesGrand River
LocationIn Grand Ledge
RouteState Highway 100
CountyEaton County
StateMichigan
Coordinates42.75493, -84.74332
Functional classUrban Minor 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
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 protection7 GoodSome minor problems.
Last inspectionJuly 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
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 adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating78.3 US tons
Inventory rating46.1 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans5
Design loadHS 25 or greater
Structure length534 ft (162.8 m)
Longest span106 ft (32.2 m)
Deck width66 ft (20.1 m)
Roadway width48 ft (14.6 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic13,838 (2007)
Projected traffic15,073 by 2018
Trucks4%
Lanes on structure3
Traffic directionTwo-way traffic
CarriesHighway and pedestrian
CrossesWaterway
Detour if closed3.7 mi (6 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 proposedDeck replacement with only incidental widening
Estimated improvement cost—
NavigationNo navigation control on waterway

Frequently asked questions

When was M-100 over Grand River built?

It was built in 1989, making it 36 years old in 2025.

What condition is M-100 over Grand 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 July 2023.

How much traffic does M-100 over Grand River carry?

About 13,838 vehicles per day (2007 count), of which roughly 4% are trucks.

How long is M-100 over Grand River?

The structure is 534 ft (162.8 m) long with a longest span of 106 ft (32.2 m) and a deck 66 ft wide.

Who owns M-100 over Grand River?

It is owned by the State Highway Agency.