US Bridges

SE White Oak Av over Big Slough CR

FairPosted for load

Johnson County, Iowa · 078051104 · Structure no. 000000000202910

Built
1920
105 years old
Condition
Fair
inspected April 2023
Type
Stringer/Multi-beam or Girder
Steel
Length
30 ft
1 main span
Daily traffic
35
2021 count
Owner
County
County Highway Agency

About this bridge

SE White Oak Av over Big Slough CR is a steel stringer/multi-beam or girder carrying SE White Oak Av over Big Slough CR in Johnson County, Iowa. It was built in 1920, so it is 105 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 5 out of 9. The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound. Its operating status is: posted for load restriction.

It carries about 35 vehicles a day, projected to reach 35 by 2043. The structure is 30 ft (9.1 m) long and 16 ft wide. If it were closed, the detour would be 3.7 mi (6 km).

Location

Open in Google Maps
CarriesSE White Oak Av
CrossesBig Slough CR
Location078051104
RouteCounty Highway 0
CountyJohnson County
StateIowa
Coordinates41.57233, -91.39589
Functional classRural Local

Condition and inspection

Fair

The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.

ComponentRatingMeaning
Deck5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionApril 2023
Inspection intervalevery 24 months
Operating statusPosted for load restriction
ScourFoundations stable; scour above top of footing
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Deck geometry8: Equal to present desirable criteria
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating31.7 US tons
Inventory rating19.8 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel
DeckConcrete, cast-in-place
Main spans1
Design loadH 15
Structure length30 ft (9.1 m)
Longest span30 ft (9.1 m)
Deck width16 ft (4.8 m)
Roadway width16 ft (4.8 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic35 (2021)
Projected traffic35 by 2043
Trucks0%
Lanes on structure1
Traffic directionOne-lane bridge for two-way traffic
CarriesHighway
CrossesWaterway
Detour if closed3.7 mi (6 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerCounty Highway Agency
Maintained byCounty Highway Agency
Historic statusNot eligible for the National Register of Historic Places
Work proposedReplacement because of substandard load-carrying capacity or roadway geometry
Estimated improvement cost—
NavigationNo navigation control on waterway

Frequently asked questions

When was SE White Oak Av over Big Slough CR built?

It was built in 1920, making it 105 years old in 2025.

What condition is SE White Oak Av over Big Slough CR 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 SE White Oak Av over Big Slough CR carry?

About 35 vehicles per day (2021 count).

How long is SE White Oak Av over Big Slough CR?

The structure is 30 ft (9.1 m) long with a longest span of 30 ft (9.1 m) and a deck 16 ft wide.

Who owns SE White Oak Av over Big Slough CR?

It is owned by the County Highway Agency.