US Bridges

Grassmere Road over Pinnebog River

Fair

Huron County, Michigan · Sec. 25 Lake Twp. · Structure no. 000000000003608

Built
1996
29 years old
Condition
Fair
inspected August 2023
Type
Box Beam or Girders - Multiple
Prestressed Concrete
Length
157 ft
3 main spans
Daily traffic
675
2009 count
Owner
County
County Highway Agency

About this bridge

Grassmere Road over Pinnebog River is a prestressed concrete box beam or girders - multiple carrying Grassmere Road over Pinnebog River in Huron County, Michigan. It was built in 1996, so it is 29 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 675 vehicles a day, projected to reach 1,210 by 2029. The structure is 157 ft (47.8 m) long and 34 ft wide. If it were closed, the detour would be 6.8 mi (11 km).

Location

Open in Google Maps
CarriesGrassmere Road
CrossesPinnebog River
LocationSec. 25 Lake Twp.
RouteCounty Highway 0
CountyHuron County
StateMichigan
Coordinates43.95074, -83.1265
Functional classRural Local

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.
Channel and channel protection7 GoodSome minor problems.
Last inspectionAugust 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour within limits of footing or piles
Structural evaluation6: Equal to present minimum criteria
Deck geometry6: Equal to present minimum criteria
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment3: Basically intolerable, requiring high priority of corrective action
Operating rating52.9 US tons
Inventory rating41.1 US tons

Structure

Structure typeBox Beam or Girders - Multiple
MaterialPrestressed Concrete
DeckConcrete, precast panels
Main spans3
Design loadHS 20
Structure length157 ft (47.8 m)
Longest span63 ft (19.2 m)
Deck width34 ft (10.5 m)
Roadway width31 ft (9.6 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic675 (2009)
Projected traffic1,210 by 2029
Trucks—
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed6.8 mi (11 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerCounty Highway Agency
Maintained byCounty 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 Grassmere Road over Pinnebog River built?

It was built in 1996, making it 29 years old in 2025.

What condition is Grassmere Road over Pinnebog 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 August 2023.

How much traffic does Grassmere Road over Pinnebog River carry?

About 675 vehicles per day (2009 count).

How long is Grassmere Road over Pinnebog River?

The structure is 157 ft (47.8 m) long with a longest span of 63 ft (19.2 m) and a deck 34 ft wide.

Who owns Grassmere Road over Pinnebog River?

It is owned by the County Highway Agency.