US Bridges

Whittemore RD over Au Gres River

Fair

Iosco County, Michigan · 1.75 MI E of Whittemore · Structure no. 000000000004134

Built
1975
50 years old
Condition
Fair
inspected June 2024
Type
Box Beam or Girders - Multiple
Prestressed Concrete
Length
105 ft
2 main spans
Daily traffic
1,090
2006 count
Owner
County
County Highway Agency

About this bridge

Whittemore RD over Au Gres River is a prestressed concrete box beam or girders - multiple carrying Whittemore RD over Au Gres River in Iosco County, Michigan. It was built in 1975, so it is 50 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 1,090 vehicles a day, roughly 10% of them trucks, projected to reach 1,960 by 2026. The structure is 105 ft (32 m) long and 31 ft wide. If it were closed, the detour would be 6.2 mi (10 km).

Location

Open in Google Maps
CarriesWhittemore RD
CrossesAu Gres River
Location1.75 MI E of Whittemore
RouteCounty Highway 3520
CountyIosco County
StateMichigan
Coordinates44.2337, -83.76951
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
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 inspectionJune 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 geometry5: Somewhat better than minimum adequacy to tolerate being left in place as is
Waterway adequacy9: Superior to present desirable criteria
Approach roadway alignment7: Better than present minimum criteria
Operating rating66.5 US tons
Inventory rating39.7 US tons

Structure

Structure typeBox Beam or Girders - Multiple
MaterialPrestressed Concrete
DeckConcrete, precast panels
Main spans2
Design loadHS 20
Structure length105 ft (32 m)
Longest span52 ft (15.8 m)
Deck width31 ft (9.3 m)
Roadway width30 ft (9.1 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic1,090 (2006)
Projected traffic1,960 by 2026
Trucks10%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed6.2 mi (10 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 Whittemore RD over Au Gres River built?

It was built in 1975, making it 50 years old in 2025.

What condition is Whittemore RD over Au Gres 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 June 2024.

How much traffic does Whittemore RD over Au Gres River carry?

About 1,090 vehicles per day (2006 count), of which roughly 10% are trucks.

How long is Whittemore RD over Au Gres River?

The structure is 105 ft (32 m) long with a longest span of 52 ft (15.8 m) and a deck 31 ft wide.

Who owns Whittemore RD over Au Gres River?

It is owned by the County Highway Agency.