US Bridges

320th ST over Field Stream

Good

Carroll County, Iowa · 082362701 · Structure no. 000000000093961

Built
2020
5 years old
Condition
Good
inspected October 2024
Type
Slab
Concrete Continuous
Length
73 ft
3 main spans
Daily traffic
29
2022 count
Owner
County
County Highway Agency

About this bridge

320th ST over Field Stream is a concrete continuous slab carrying 320th ST over Field Stream in Carroll County, Iowa. It was built in 2020, so it is 5 years old, younger than the Iowa average of 45.5 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 29 vehicles a day, projected to reach 29 by 2044. The structure is 73 ft (22.3 m) long and 33 ft wide. If it were closed, the detour would be 1.9 mi (3 km).

Location

Open in Google Maps
Carries320th ST
CrossesField Stream
Location082362701
RouteCounty Highway 0
CountyCarroll County
StateIowa
Coordinates41.89188, -95.02701
Functional classRural Local

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 protection9 ExcellentNo problems noted.
Last inspectionOctober 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation8: Equal to present desirable criteria
Deck geometry7: Better than present minimum criteria
Waterway adequacy6: Equal to present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating59 US tons
Inventory rating45.3 US tons

Structure

Structure typeSlab
MaterialConcrete Continuous
DeckConcrete, cast-in-place
Main spans3
Design loadHL 93
Structure length73 ft (22.3 m)
Longest span28 ft (8.5 m)
Deck width33 ft (10.1 m)
Roadway width31 ft (9.3 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic29 (2022)
Projected traffic29 by 2044
Trucks0%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed1.9 mi (3 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 320th ST over Field Stream built?

It was built in 2020, making it 5 years old in 2025.

What condition is 320th ST over Field Stream 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 October 2024.

How much traffic does 320th ST over Field Stream carry?

About 29 vehicles per day (2022 count).

How long is 320th ST over Field Stream?

The structure is 73 ft (22.3 m) long with a longest span of 28 ft (8.5 m) and a deck 33 ft wide.

Who owns 320th ST over Field Stream?

It is owned by the County Highway Agency.