US Bridges

Ia 1 over Mill Creek

Fair

Johnson County, Iowa · 0.1 Mi. N of Solon · Structure no. 000000000031841

Built
1985
40 years old
Condition
Fair
inspected July 2023
Type
Slab
Concrete Continuous
Length
93 ft
3 main spans
Daily traffic
6,000
2022 count
Owner
State
State Highway Agency

About this bridge

Ia 1 over Mill Creek is a concrete continuous slab carrying Ia 1 over Mill Creek in Johnson County, Iowa. It was built in 1985, so it is 40 years old, younger 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 6,000 vehicles a day, roughly 14% of them trucks, projected to reach 6,000 by 2042. The structure is 93 ft (28.3 m) long and 43 ft wide. If it were closed, the detour would be 24.2 mi (39 km).

Location

Open in Google Maps
CarriesIa 1
CrossesMill Creek
Location0.1 Mi. N of Solon
RouteState Highway 1
CountyJohnson County
StateIowa
Coordinates41.81233, -91.49388
Functional classRural Principal Arterial - Other

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 protection8 Very GoodNo problems noted.
Last inspectionJuly 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation6: Equal to present minimum criteria
Deck geometry5: Somewhat better than minimum adequacy to tolerate being left in place as is
Waterway adequacy6: Equal to present minimum criteria
Approach roadway alignment7: Better than present minimum criteria
Operating rating99 US tons
Inventory rating59 US tons

Structure

Structure typeSlab
MaterialConcrete Continuous
DeckConcrete, cast-in-place
Main spans3
Design loadHS 20 + Mod
Structure length93 ft (28.3 m)
Longest span35 ft (10.7 m)
Deck width43 ft (13.2 m)
Roadway width40 ft (12.2 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic6,000 (2022)
Projected traffic6,000 by 2042
Trucks14%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed24.2 mi (39 km)
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—
NavigationNo navigation control on waterway

Frequently asked questions

When was Ia 1 over Mill Creek built?

It was built in 1985, making it 40 years old in 2025.

What condition is Ia 1 over Mill Creek 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 July 2023.

How much traffic does Ia 1 over Mill Creek carry?

About 6,000 vehicles per day (2022 count), of which roughly 14% are trucks.

How long is Ia 1 over Mill Creek?

The structure is 93 ft (28.3 m) long with a longest span of 35 ft (10.7 m) and a deck 43 ft wide.

Who owns Ia 1 over Mill Creek?

It is owned by the State Highway Agency.