US Bridges

120th ST over Indian Creek

Poor

Plymouth County, Iowa · 093481401 · Structure no. 000000000277610

Built
1900
125 years old
Condition
Poor
inspected September 2024
Type
Stringer/Multi-beam or Girder
Wood or Timber
Length
30 ft
2 main spans
Daily traffic
20
2022 count
Owner
County
County Highway Agency

About this bridge

120th ST over Indian Creek is a wood or timber stringer/multi-beam or girder carrying 120th ST over Indian Creek in Plymouth 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 poor condition with a lowest component rating of 4 out of 9. The lowest-rated primary component is rated 4 or below, indicating advanced deterioration. Poor does not mean unsafe; such bridges are inspected more often and may carry load restrictions.

It carries about 20 vehicles a day, projected to reach 20 by 2044. The structure is 30 ft (9.1 m) long and 20 ft wide. If it were closed, the detour would be 1.9 mi (3 km).

Location

Open in Google Maps
Carries120th ST
CrossesIndian Creek
Location093481401
RouteCounty Highway 0
CountyPlymouth County
StateIowa
Coordinates42.88048, -96.48413
Functional classRural Local

Condition and inspection

Poor

The lowest-rated primary component is rated 4 or below, indicating advanced deterioration. Poor does not mean unsafe; such bridges are inspected more often and may carry load restrictions.

ComponentRatingMeaning
Deck7 GoodSome minor problems.
Superstructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Substructure4 PoorAdvanced section loss, deterioration, spalling or scour.
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionSeptember 2024
Inspection intervalevery 12 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation4: Meets minimum tolerable limits to be left in place as is
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 rating33.8 US tons
Inventory rating23.4 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialWood or Timber
DeckWood or timber
Main spans2
Design loadHS 20
Structure length30 ft (9.1 m)
Longest span15 ft (4.6 m)
Deck width20 ft (6.2 m)
Roadway width20 ft (6.1 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic20 (2022)
Projected traffic20 by 2044
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 statusPossibly eligible for the National Register; requires further investigation
Work proposedReplacement because of substandard load-carrying capacity or roadway geometry
Estimated improvement cost$165,000 (2024 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was 120th ST over Indian Creek built?

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

What condition is 120th ST over Indian Creek in?

The National Bridge Inventory rates it in poor condition. The lowest-rated primary component is rated 4 or below, indicating advanced deterioration. Poor does not mean unsafe; such bridges are inspected more often and may carry load restrictions. The last reported inspection was in September 2024.

How much traffic does 120th ST over Indian Creek carry?

About 20 vehicles per day (2022 count).

How long is 120th ST over Indian Creek?

The structure is 30 ft (9.1 m) long with a longest span of 15 ft (4.6 m) and a deck 20 ft wide.

Who owns 120th ST over Indian Creek?

It is owned by the County Highway Agency.