US Bridges

SW Observatory over Branch of Crooked Creek

Fair

Johnson County, Iowa · 078062804 · Structure no. 000000000203401

Built
1984
41 years old
Condition
Fair
inspected April 2023
Type
Stringer/Multi-beam or Girder
Steel
Length
39 ft
1 main span
Daily traffic
122
2021 count
Owner
County
County Highway Agency

About this bridge

SW Observatory over Branch of Crooked Creek is a steel stringer/multi-beam or girder carrying SW Observatory over Branch of Crooked Creek in Johnson County, Iowa. It was built in 1984, so it is 41 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 5 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 122 vehicles a day, projected to reach 122 by 2043. The structure is 39 ft (11.9 m) long and 24 ft wide.

Location

Open in Google Maps
CarriesSW Observatory
CrossesBranch of Crooked Creek
Location078062804
RouteCounty Highway 0
CountyJohnson County
StateIowa
Coordinates41.53357, -91.56062
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
Deck6 SatisfactoryStructural elements show some minor deterioration.
Superstructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionApril 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Deck geometry4: Meets minimum tolerable limits to be left in place as is
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating34.4 US tons
Inventory rating20.2 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel
DeckConcrete, cast-in-place
Main spans1
Design loadHS 20
Structure length39 ft (11.9 m)
Longest span35 ft (10.7 m)
Deck width24 ft (7.3 m)
Roadway width22 ft (6.7 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic122 (2021)
Projected traffic122 by 2043
Trucks0%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed—
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 proposedNone recorded
Estimated improvement cost—
NavigationNo navigation control on waterway

Frequently asked questions

When was SW Observatory over Branch of Crooked Creek built?

It was built in 1984, making it 41 years old in 2025.

What condition is SW Observatory over Branch of Crooked 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 April 2023.

How much traffic does SW Observatory over Branch of Crooked Creek carry?

About 122 vehicles per day (2021 count).

How long is SW Observatory over Branch of Crooked Creek?

The structure is 39 ft (11.9 m) long with a longest span of 35 ft (10.7 m) and a deck 24 ft wide.

Who owns SW Observatory over Branch of Crooked Creek?

It is owned by the County Highway Agency.