US Bridges

Ia 471 over Branch Boyer River

Good

Sac County, Iowa · 0.7 Mi. N of Jct. Ia 175 · Structure no. 000000000046671

Built
1984
41 years old
Condition
Good
inspected November 2024
Type
Culvert
Concrete Continuous
Length
25 ft
2 main spans
Daily traffic
1,070
2022 count
Owner
State
State Highway Agency

About this bridge

Ia 471 over Branch Boyer River is a concrete continuous culvert carrying Ia 471 over Branch Boyer River in Sac County, Iowa. It was built in 1984, so it is 41 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 7 out of 9. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

It carries about 1,070 vehicles a day, roughly 26% of them trucks, projected to reach 1,070 by 2044. The structure is 25 ft (7.6 m) long. If it were closed, the detour would be 6.2 mi (10 km).

Location

Open in Google Maps
CarriesIa 471
CrossesBranch Boyer River
Location0.7 Mi. N of Jct. Ia 175
RouteState Highway 471
CountySac County
StateIowa
Coordinates42.32234, -95.14832
Functional classRural Minor Arterial

Condition and inspection

Good

All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

ComponentRatingMeaning
Channel and channel protection7 GoodSome minor problems.
Culvert7 GoodSome minor problems.
Last inspectionNovember 2024
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 adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating37.9 US tons
Inventory rating22.7 US tons

Structure

Structure typeCulvert
MaterialConcrete Continuous
DeckNot applicable
Main spans2
Design loadHS 20
Structure length25 ft (7.6 m)
Longest span12 ft (3.7 m)
Deck width0 ft (0 m)
Roadway width0 ft (0 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic1,070 (2022)
Projected traffic1,070 by 2044
Trucks26%
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 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 Ia 471 over Branch Boyer River built?

It was built in 1984, making it 41 years old in 2025.

What condition is Ia 471 over Branch Boyer River 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 November 2024.

How much traffic does Ia 471 over Branch Boyer River carry?

About 1,070 vehicles per day (2022 count), of which roughly 26% are trucks.

How long is Ia 471 over Branch Boyer River?

The structure is 25 ft (7.6 m) long with a longest span of 12 ft (3.7 m).

Who owns Ia 471 over Branch Boyer River?

It is owned by the State Highway Agency.