US Bridges

Ia 1 over Ralston Creek

Fair

Johnson County, Iowa · 0.6 Mi. N of N Jct. US 6 · Structure no. 000000000031740

Built
1932
93 years old, rebuilt 2004
Condition
Fair
inspected July 2024
Type
Stringer/Multi-beam or Girder
Steel Continuous
Length
61 ft
2 main spans
Daily traffic
13,500
2022 count
Owner
State
State Highway Agency

About this bridge

Ia 1 over Ralston Creek is a steel continuous stringer/multi-beam or girder carrying Ia 1 over Ralston Creek in Johnson County, Iowa. It was built in 1932 and reconstructed in 2004, so it is 93 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 13,500 vehicles a day, roughly 3% of them trucks, projected to reach 13,500 by 2044. The structure is 61 ft (18.6 m) long and 79 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

Open in Google Maps
CarriesIa 1
CrossesRalston Creek
Location0.6 Mi. N of N Jct. US 6
RouteState Highway 1
CountyJohnson County
StateIowa
Coordinates41.65781, -91.52898
Functional classUrban Other Principal 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
Deck7 GoodSome minor problems.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection7 GoodSome minor problems.
Last inspectionJuly 2024
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 geometry2: Basically intolerable, requiring high priority of replacement
Waterway adequacy6: Equal to present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating59.7 US tons
Inventory rating35.8 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel Continuous
DeckConcrete, cast-in-place
Main spans2
Design loadHS 20
Structure length61 ft (18.6 m)
Longest span28 ft (8.5 m)
Deck width79 ft (24.2 m)
Roadway width60 ft (18.3 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic13,500 (2022)
Projected traffic13,500 by 2044
Trucks3%
Lanes on structure5
Traffic directionTwo-way traffic
CarriesHighway and pedestrian
CrossesWaterway
Detour if closed1.2 mi (2 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 Ralston Creek built?

It was built in 1932, making it 93 years old in 2025. It was reconstructed in 2004.

What condition is Ia 1 over Ralston 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 2024.

How much traffic does Ia 1 over Ralston Creek carry?

About 13,500 vehicles per day (2022 count), of which roughly 3% are trucks.

How long is Ia 1 over Ralston Creek?

The structure is 61 ft (18.6 m) long with a longest span of 28 ft (8.5 m) and a deck 79 ft wide.

Who owns Ia 1 over Ralston Creek?

It is owned by the State Highway Agency.