US Bridges

320th ST over Stream

Good

Adair County, Iowa · 74331939 · Structure no. 000000000055411

Built
2014
11 years old
Condition
Good
inspected April 2024
Type
Stringer/Multi-beam or Girder
Steel
Length
70 ft
1 main span
Daily traffic
11
2022 count
Owner
County
County Highway Agency

About this bridge

320th ST over Stream is a steel stringer/multi-beam or girder carrying 320th ST over Stream in Adair County, Iowa. It was built in 2014, so it is 11 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 11 vehicles a day, projected to reach 11 by 2043. The structure is 70 ft (21.3 m) long and 25 ft wide. If it were closed, the detour would be 1.9 mi (3 km).

Location

Open in Google Maps
Carries320th ST
CrossesStream
Location74331939
RouteCounty Highway 0
CountyAdair County
StateIowa
Coordinates41.18759, -94.69524
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 inspectionApril 2024
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 adequacy7: Better than present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating64.6 US tons
Inventory rating49.6 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel
DeckConcrete, cast-in-place
Main spans1
Design loadHS 20
Structure length70 ft (21.3 m)
Longest span69 ft (21 m)
Deck width25 ft (7.5 m)
Roadway width24 ft (7.3 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic11 (2022)
Projected traffic11 by 2043
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 Stream built?

It was built in 2014, making it 11 years old in 2025.

What condition is 320th ST over 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 April 2024.

How much traffic does 320th ST over Stream carry?

About 11 vehicles per day (2022 count).

How long is 320th ST over Stream?

The structure is 70 ft (21.3 m) long with a longest span of 69 ft (21 m) and a deck 25 ft wide.

Who owns 320th ST over Stream?

It is owned by the County Highway Agency.