US Bridges

320th ST over Drainage

FairPosted for load

Buchanan County, Iowa · 087093003 · Structure no. 000000000081450

Built
2005
20 years old
Condition
Fair
inspected January 2024
Type
Other
Steel
Length
68 ft
1 main span
Daily traffic
30
2022 count
Owner
County
County Highway Agency

About this bridge

320th ST over Drainage is a steel other carrying 320th ST over Drainage in Buchanan County, Iowa. It was built in 2005, so it is 20 years old, younger 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. Its operating status is: posted for other load-capacity restriction.

It carries about 30 vehicles a day, projected to reach 30 by 2044. The structure is 68 ft (20.7 m) long and 19 ft wide.

Location

Open in Google Maps
Carries320th ST
CrossesDrainage
Location087093003
RouteCounty Highway 0
CountyBuchanan County
StateIowa
Coordinates42.32651, -91.93839
Functional classRural Local

Condition and inspection

Fair

The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.

ComponentRatingMeaning
Deck6 SatisfactoryStructural elements show some minor deterioration.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionJanuary 2024
Inspection intervalevery 24 months
Operating statusPosted for other load-capacity restriction
ScourFoundations stable; scour above top of footing
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating34.2 US tons
Inventory rating19.1 US tons

Structure

Structure typeOther
MaterialSteel
DeckSteel plate
Main spans1
Design loadHS 20
Structure length68 ft (20.7 m)
Longest span66 ft (20.1 m)
Deck width19 ft (5.8 m)
Roadway width17 ft (5.2 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic30 (2022)
Projected traffic30 by 2044
Trucks0%
Lanes on structure2
Traffic directionOne-lane bridge for two-way traffic
CarriesHighway
CrossesWaterway
Detour if closed—
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 Drainage built?

It was built in 2005, making it 20 years old in 2025.

What condition is 320th ST over Drainage 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 January 2024.

How much traffic does 320th ST over Drainage carry?

About 30 vehicles per day (2022 count).

How long is 320th ST over Drainage?

The structure is 68 ft (20.7 m) long with a longest span of 66 ft (20.1 m) and a deck 19 ft wide.

Who owns 320th ST over Drainage?

It is owned by the County Highway Agency.