US Bridges

Ia 471 over Drainage Ditch

Fair

Sac County, Iowa · 0.2 Mi. N of SR D-36 · Structure no. 000000000046560

Built
1933
92 years old, rebuilt 1969
Condition
Fair
inspected September 2023
Type
Culvert
Concrete Continuous
Length
22 ft
2 main spans
Daily traffic
1,320
2022 count
Owner
State
State Highway Agency

About this bridge

Ia 471 over Drainage Ditch is a concrete continuous culvert carrying Ia 471 over Drainage Ditch in Sac County, Iowa. It was built in 1933 and reconstructed in 1969, so it is 92 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 1,320 vehicles a day, roughly 21% of them trucks, projected to reach 1,320 by 2043. The structure is 22 ft (6.7 m) long. If it were closed, the detour would be 6.2 mi (10 km).

Location

Open in Google Maps
CarriesIa 471
CrossesDrainage Ditch
Location0.2 Mi. N of SR D-36
RouteState Highway 471
CountySac County
StateIowa
Coordinates42.42492, -95.14792
Functional classRural Minor Arterial

Condition and inspection

Fair

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

ComponentRatingMeaning
Channel and channel protection5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Culvert5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Last inspectionSeptember 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
Waterway adequacy6: Equal to present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating27 US tons
Inventory rating20 US tons

Structure

Structure typeCulvert
MaterialConcrete Continuous
DeckNot applicable
Main spans2
Design loadH 20
Structure length22 ft (6.7 m)
Longest span10 ft (3 m)
Deck width0 ft (0 m)
Roadway width0 ft (0 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic1,320 (2022)
Projected traffic1,320 by 2043
Trucks21%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed6.2 mi (10 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerState Highway Agency
Maintained byState Highway Agency
Historic statusPossibly eligible for the National Register; requires further investigation
Work proposedNone recorded
Estimated improvement cost—
NavigationNo navigation control on waterway

Frequently asked questions

When was Ia 471 over Drainage Ditch built?

It was built in 1933, making it 92 years old in 2025. It was reconstructed in 1969.

What condition is Ia 471 over Drainage Ditch 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 September 2023.

How much traffic does Ia 471 over Drainage Ditch carry?

About 1,320 vehicles per day (2022 count), of which roughly 21% are trucks.

How long is Ia 471 over Drainage Ditch?

The structure is 22 ft (6.7 m) long with a longest span of 10 ft (3 m).

Who owns Ia 471 over Drainage Ditch?

It is owned by the State Highway Agency.