US Bridges

120th Street over Middle Tarkio River

Good

Page County, Iowa · 070381303 · Structure no. 000000000268171

Built
2003
22 years old
Condition
Good
inspected November 2022
Type
Stringer/Multi-beam or Girder
Prestressed Concrete
Length
189 ft
3 main spans
Daily traffic
20
2022 count
Owner
County
County Highway Agency

About this bridge

120th Street over Middle Tarkio River is a prestressed concrete stringer/multi-beam or girder carrying 120th Street over Middle Tarkio River in Page County, Iowa. It was built in 2003, so it is 22 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 8 out of 9. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

It carries about 20 vehicles a day, projected to reach 20 by 2042. The structure is 189 ft (57.6 m) long and 27 ft wide. If it were closed, the detour would be 5 mi (8 km).

Carries120th Street
CrossesMiddle Tarkio River
Location070381303
RouteCounty Highway 0
StateIowa
Coordinates40.87199, -95.15763
Functional classRural Local

Condition and inspection

Good

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

ComponentRatingMeaning
Deck8 Very GoodNo problems noted.
Superstructure8 Very GoodNo problems noted.
Substructure8 Very GoodNo problems noted.
Channel and channel protection5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Last inspectionNovember 2022
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation8: Equal to present desirable criteria
Deck geometry6: Equal to present minimum criteria
Waterway adequacy7: Better than present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating81.9 US tons
Inventory rating45.2 US tons

Structure

MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans3
Design loadHS 20
Structure length189 ft (57.6 m)
Longest span69 ft (21 m)
Deck width27 ft (8.3 m)
Roadway width24 ft (7.3 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic20 (2022)
Projected traffic20 by 2042
Trucks0%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed5 mi (8 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 120th Street over Middle Tarkio River built?

It was built in 2003, making it 22 years old in 2025.

What condition is 120th Street over Middle Tarkio River 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 November 2022.

How much traffic does 120th Street over Middle Tarkio River carry?

About 20 vehicles per day (2022 count).

How long is 120th Street over Middle Tarkio River?

The structure is 189 ft (57.6 m) long with a longest span of 69 ft (21 m) and a deck 27 ft wide.

Who owns 120th Street over Middle Tarkio River?

It is owned by the County Highway Agency.