US Bridges

1280 320th ST over Dd 1&2

Fair

Hancock County, Iowa · 097251301 · Structure no. 000000000174300

Built
1956
69 years old
Condition
Fair
inspected April 2023
Type
Stringer/Multi-beam or Girder
Prestressed Concrete
Length
45 ft
1 main span
Daily traffic
63
2021 count
Owner
County
County Highway Agency

About this bridge

1280 320th ST over Dd 1&2 is a prestressed concrete stringer/multi-beam or girder carrying 1280 320th ST over Dd 1&2 in Hancock County, Iowa. It was built in 1956, so it is 69 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 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 63 vehicles a day, projected to reach 63 by 2043. The structure is 45 ft (13.7 m) long and 22 ft wide. If it were closed, the detour would be 1.9 mi (3 km).

Location

Open in Google Maps
Carries1280 320th ST
CrossesDd 1&2
Location097251301
RouteCounty Highway 0
CountyHancock County
StateIowa
Coordinates43.22728, -93.73681
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
Deck5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionApril 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
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 adequacy6: Equal to present minimum criteria
Approach roadway alignment5: Somewhat better than minimum adequacy to tolerate being left in place as is
Operating rating54.5 US tons
Inventory rating27.7 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans1
Design loadH 15
Structure length45 ft (13.7 m)
Longest span42 ft (12.8 m)
Deck width22 ft (6.6 m)
Roadway width20 ft (6.1 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic63 (2021)
Projected traffic63 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 proposedReplacement because of substandard load-carrying capacity or roadway geometry
Estimated improvement cost—
NavigationNo navigation control on waterway

Frequently asked questions

When was 1280 320th ST over Dd 1&2 built?

It was built in 1956, making it 69 years old in 2025.

What condition is 1280 320th ST over Dd 1&2 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 April 2023.

How much traffic does 1280 320th ST over Dd 1&2 carry?

About 63 vehicles per day (2021 count).

How long is 1280 320th ST over Dd 1&2?

The structure is 45 ft (13.7 m) long with a longest span of 42 ft (12.8 m) and a deck 22 ft wide.

Who owns 1280 320th ST over Dd 1&2?

It is owned by the County Highway Agency.