US Bridges

310th over Winnebago River

Fair

Cerro Gordo County, Iowa · 097222001 · Structure no. 000000000106950

Built
1960
65 years old
Condition
Fair
inspected February 2024
Type
Stringer/Multi-beam or Girder
Prestressed Concrete
Length
168 ft
3 main spans
Daily traffic
992
2022 count
Owner
County
County Highway Agency

About this bridge

310th over Winnebago River is a prestressed concrete stringer/multi-beam or girder carrying 310th over Winnebago River in Cerro Gordo County, Iowa. It was built in 1960, so it is 65 years old, older than the Iowa average of 45.5 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 992 vehicles a day, projected to reach 992 by 2044. The structure is 168 ft (51.2 m) long and 26 ft wide. If it were closed, the detour would be 16.8 mi (27 km).

Location

Open in Google Maps
Carries310th
CrossesWinnebago River
Location097222001
RouteCounty Highway 0
CountyCerro Gordo County
StateIowa
Coordinates43.21334, -93.47353
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
Deck7 GoodSome minor problems.
Superstructure7 GoodSome minor problems.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionFebruary 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation6: Equal to present minimum criteria
Deck geometry4: Meets minimum tolerable limits to be left in place as is
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating45.7 US tons
Inventory rating27.3 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans3
Design loadH 15
Structure length168 ft (51.2 m)
Longest span55 ft (16.8 m)
Deck width26 ft (7.9 m)
Roadway width24 ft (7.3 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic992 (2022)
Projected traffic992 by 2044
Trucks0%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed16.8 mi (27 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 proposedReplacement because of substandard load-carrying capacity or roadway geometry
Estimated improvement cost—
NavigationNo navigation control on waterway

Frequently asked questions

When was 310th over Winnebago River built?

It was built in 1960, making it 65 years old in 2025.

What condition is 310th over Winnebago 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 February 2024.

How much traffic does 310th over Winnebago River carry?

About 992 vehicles per day (2022 count).

How long is 310th over Winnebago River?

The structure is 168 ft (51.2 m) long with a longest span of 55 ft (16.8 m) and a deck 26 ft wide.

Who owns 310th over Winnebago River?

It is owned by the County Highway Agency.