US Bridges

257th ST over Unnamed Stream

Good

Jefferson County, Iowa · 071102407 · Structure no. 000000000200421

Built
2022
3 years old
Condition
Good
inspected February 2023
Type
Slab
Concrete Continuous
Length
91 ft
3 main spans
Daily traffic
190
2022 count
Owner
County
County Highway Agency

About this bridge

257th ST over Unnamed Stream is a concrete continuous slab carrying 257th ST over Unnamed Stream in Jefferson County, Iowa. It was built in 2022, so it is 3 years old, younger than the Iowa average of 45.5 years.

The most recent inspection reported to the Federal Highway Administration rates it in good condition with a lowest component rating of 9 out of 9. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

It carries about 190 vehicles a day, projected to reach 190 by 2043. The structure is 91 ft (27.7 m) long and 27 ft wide. If it were closed, the detour would be 1.9 mi (3 km).

Location

Open in Google Maps
Carries257th ST
CrossesUnnamed Stream
Location071102407
RouteCounty Highway 0
CountyJefferson County
StateIowa
Coordinates40.93507, -91.96616
Functional classRural Minor Collector

Condition and inspection

Good

All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

ComponentRatingMeaning
Deck9 ExcellentNo problems noted.
Superstructure9 ExcellentNo problems noted.
Substructure9 ExcellentNo problems noted.
Channel and channel protection8 Very GoodNo problems noted.
Last inspectionFebruary 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour within limits of footing or piles
Structural evaluation9: Superior to present desirable criteria
Deck geometry5: Somewhat better than minimum adequacy to tolerate being left in place as is
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating53.6 US tons
Inventory rating41.4 US tons

Structure

Structure typeSlab
MaterialConcrete Continuous
DeckConcrete, cast-in-place
Main spans3
Design loadHL 93
Structure length91 ft (27.7 m)
Longest span35 ft (10.7 m)
Deck width27 ft (8.3 m)
Roadway width25 ft (7.5 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic190 (2022)
Projected traffic190 by 2043
Trucks0%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed1.9 mi (3 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 proposedOther structural work, including hydraulic replacements
Estimated improvement cost—
NavigationNo navigation control on waterway

Frequently asked questions

When was 257th ST over Unnamed Stream built?

It was built in 2022, making it 3 years old in 2025.

What condition is 257th ST over Unnamed Stream in?

The National Bridge Inventory rates it in good condition. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted. The last reported inspection was in February 2023.

How much traffic does 257th ST over Unnamed Stream carry?

About 190 vehicles per day (2022 count).

How long is 257th ST over Unnamed Stream?

The structure is 91 ft (27.7 m) long with a longest span of 35 ft (10.7 m) and a deck 27 ft wide.

Who owns 257th ST over Unnamed Stream?

It is owned by the County Highway Agency.