US Bridges

Ia 9 over Rock River

Fair

Lyon County, Iowa · 0.5 Mi. E of E Jct. US 75 · Structure no. 000000000034645

Built
1974
51 years old
Condition
Fair
inspected April 2023
Type
Stringer/Multi-beam or Girder
Steel Continuous
Length
353 ft
4 main spans
Daily traffic
3,920
2022 count
Owner
State
State Highway Agency

About this bridge

Ia 9 over Rock River is a steel continuous stringer/multi-beam or girder carrying Ia 9 over Rock River in Lyon County, Iowa. It was built in 1974, so it is 51 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 6 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 3,920 vehicles a day, roughly 13% of them trucks, projected to reach 3,920 by 2042. The structure is 353 ft (107.6 m) long and 71 ft wide. If it were closed, the detour would be 5 mi (8 km).

Location

Open in Google Maps
CarriesIa 9
CrossesRock River
Location0.5 Mi. E of E Jct. US 75
RouteState Highway 9
CountyLyon County
StateIowa
Coordinates43.43183, -96.1651
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
Deck6 SatisfactoryStructural elements show some minor deterioration.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure7 GoodSome minor problems.
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionApril 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour within limits of footing or piles
Structural evaluation6: Equal to present minimum criteria
Deck geometry5: 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 rating67.2 US tons
Inventory rating40.3 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel Continuous
DeckConcrete, cast-in-place
Main spans4
Design loadHS 20
Structure length353 ft (107.6 m)
Longest span114 ft (34.7 m)
Deck width71 ft (21.5 m)
Roadway width56 ft (17.1 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic3,920 (2022)
Projected traffic3,920 by 2042
Trucks13%
Lanes on structure4
Traffic directionTwo-way traffic
CarriesHighway and pedestrian
CrossesWaterway
Detour if closed5 mi (8 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 9 over Rock River built?

It was built in 1974, making it 51 years old in 2025.

What condition is Ia 9 over Rock River 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 Ia 9 over Rock River carry?

About 3,920 vehicles per day (2022 count), of which roughly 13% are trucks.

How long is Ia 9 over Rock River?

The structure is 353 ft (107.6 m) long with a longest span of 114 ft (34.7 m) and a deck 71 ft wide.

Who owns Ia 9 over Rock River?

It is owned by the State Highway Agency.