US 20 over Dd 9 & 13

Good

Calhoun County, Iowa · 3.0 Mi. E of Jct. Ia 4 · Structure no. 000000000609930

Built: 2008; 17 years old
Condition: Good; inspected May 2023
Type: Culvert; Concrete Continuous
Length: 25 ft; 2 main spans
Daily traffic: 6,900; 2022 count
Owner: State; State Highway Agency

About this bridge

US 20 over Dd 9 & 13 is a concrete continuous culvert carrying US 20 over Dd 9 & 13 in Calhoun County, Iowa. It was built in 2008, so it is 17 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 6,900 vehicles a day, roughly 32% of them trucks, projected to reach 6,900 by 2042. The structure is 25 ft (7.6 m) long.

Location

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CarriesUS 20

CrossesDd 9 & 13

Location3.0 Mi. E of Jct. Ia 4

RouteU.S. Route 20

CountyCalhoun County

StateIowa

Coordinates42.44954, -94.61032

Functional classRural Principal Arterial - Other

Condition and inspection

Good

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

Component	Rating	Meaning
Channel and channel protection	7 Good	Some minor problems.
Culvert	7 Good	Some minor problems.

Last inspectionMay 2023

Inspection intervalevery 24 months

Operating statusOpen, no restriction

ScourFoundations stable; scour above top of footing

Structural evaluation7: Better than present minimum criteria

Waterway adequacy8: Equal to present desirable criteria

Approach roadway alignment8: Equal to present desirable criteria

Operating rating48.6 US tons

Inventory rating36 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 traffic6,900 (2022)

Projected traffic6,900 by 2042

Trucks32%

Lanes on structure4

Traffic directionTwo-way traffic

CarriesHighway

CrossesWaterway

Detour if closed—

TollOn a free road

National Highway SystemYes

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—

NavigationNot applicable (no waterway)

Frequently asked questions

When was US 20 over Dd 9 & 13 built?

It was built in 2008, making it 17 years old in 2025.

What condition is US 20 over Dd 9 & 13 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 May 2023.

How much traffic does US 20 over Dd 9 & 13 carry?

About 6,900 vehicles per day (2022 count), of which roughly 32% are trucks.

How long is US 20 over Dd 9 & 13?

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

Who owns US 20 over Dd 9 & 13?

It is owned by the State Highway Agency.