US Bridges

FM SW Blk Dimnd over Stream

Fair

Johnson County, Iowa · 079083405 · Structure no. 000000000204590

Built
1900
125 years old
Condition
Fair
inspected April 2023
Type
Culvert
Concrete Continuous
Length
23 ft
2 main spans
Daily traffic
970
2021 count
Owner
County
County Highway Agency

About this bridge

FM SW Blk Dimnd over Stream is a concrete continuous culvert carrying FM SW Blk Dimnd over Stream in Johnson County, Iowa. It was built in 1900, so it is 125 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.

It carries about 970 vehicles a day, roughly 20% of them trucks, projected to reach 970 by 2043. The structure is 23 ft (7 m) long. If it were closed, the detour would be 3.1 mi (5 km).

Location

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CarriesFM SW Blk Dimnd
CrossesStream
Location079083405
RouteCounty Highway 0
CountyJohnson County
StateIowa
Coordinates41.60907, -91.76178
Functional classRural Major Collector

Condition and inspection

Fair

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

ComponentRatingMeaning
Channel and channel protection5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Culvert5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
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
Waterway adequacy4: Meets minimum tolerable limits to be left in place as is
Approach roadway alignment8: Equal to present desirable criteria
Operating rating42.1 US tons
Inventory rating32.4 US tons

Structure

Structure typeCulvert
MaterialConcrete Continuous
DeckNot applicable
Main spans2
Design loadUnknown
Structure length23 ft (7 m)
Longest span11 ft (3.4 m)
Deck width0 ft (0 m)
Roadway width0 ft (0 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic970 (2021)
Projected traffic970 by 2043
Trucks20%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed3.1 mi (5 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

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

Frequently asked questions

When was FM SW Blk Dimnd over Stream built?

It was built in 1900, making it 125 years old in 2025.

What condition is FM SW Blk Dimnd over Stream 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 FM SW Blk Dimnd over Stream carry?

About 970 vehicles per day (2021 count), of which roughly 20% are trucks.

How long is FM SW Blk Dimnd over Stream?

The structure is 23 ft (7 m) long with a longest span of 11 ft (3.4 m).

Who owns FM SW Blk Dimnd over Stream?

It is owned by the County Highway Agency.