US Bridges

Rockriver Road over Rock River

Good

Alger County, Michigan · 1.1 MI S of M-28 · Structure no. 000000000000058

Built
2007
18 years old
Condition
Good
inspected September 2023
Type
Box Beam or Girders - Multiple
Prestressed Concrete
Length
60 ft
1 main span
Daily traffic
145
2006 count
Owner
County
County Highway Agency

About this bridge

Rockriver Road over Rock River is a prestressed concrete box beam or girders - multiple carrying Rockriver Road over Rock River in Alger County, Michigan. It was built in 2007, so it is 18 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 8 out of 9. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

It carries about 145 vehicles a day, projected to reach 200 by 2026. The structure is 60 ft (18.3 m) long and 28 ft wide. If it were closed, the detour would be 9.9 mi (16 km).

Location

Open in Google Maps
CarriesRockriver Road
CrossesRock River
Location1.1 MI S of M-28
CountyAlger County
StateMichigan
Coordinates46.45165, -86.92066
Functional classRural Major Collector

Condition and inspection

Good

All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

ComponentRatingMeaning
Deck8 Very GoodNo problems noted.
Superstructure8 Very GoodNo problems noted.
Substructure8 Very GoodNo problems noted.
Channel and channel protection7 GoodSome minor problems.
Last inspectionSeptember 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation8: Equal to present desirable criteria
Deck geometry6: Equal to present minimum criteria
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating72.9 US tons
Inventory rating43.8 US tons

Structure

Structure typeBox Beam or Girders - Multiple
MaterialPrestressed Concrete
DeckConcrete, precast panels
Main spans1
Design loadHS 20
Structure length60 ft (18.3 m)
Longest span56 ft (17.1 m)
Deck width28 ft (8.5 m)
Roadway width28 ft (8.5 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic145 (2006)
Projected traffic200 by 2026
Trucks0%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed9.9 mi (16 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerCounty Highway Agency
Maintained byCounty 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 Rockriver Road over Rock River built?

It was built in 2007, making it 18 years old in 2025.

What condition is Rockriver Road over Rock 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 September 2023.

How much traffic does Rockriver Road over Rock River carry?

About 145 vehicles per day (2006 count).

How long is Rockriver Road over Rock River?

The structure is 60 ft (18.3 m) long with a longest span of 56 ft (17.1 m) and a deck 28 ft wide.

Who owns Rockriver Road over Rock River?

It is owned by the County Highway Agency.