US Bridges

FM 20th ST over Br Upper Iowa River

PoorPosted for load

Howard County, Iowa · 100121601 · Structure no. 000000000183700

Built
1951
74 years old
Condition
Poor
inspected April 2024
Type
Stringer/Multi-beam or Girder
Steel
Length
61 ft
2 main spans
Daily traffic
15
2022 count
Owner
County
County Highway Agency

About this bridge

FM 20th ST over Br Upper Iowa River is a steel stringer/multi-beam or girder carrying FM 20th ST over Br Upper Iowa River in Howard County, Iowa. It was built in 1951, so it is 74 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. Its operating status is: posted for load restriction.

It carries about 15 vehicles a day, projected to reach 15 by 2044. The structure is 61 ft (18.6 m) long and 20 ft wide. If it were closed, the detour would be 6.2 mi (10 km).

Location

Open in Google Maps
CarriesFM 20th ST
CrossesBr Upper Iowa River
Location100121601
RouteCounty Highway 0
CountyHoward County
StateIowa
Coordinates43.4872, -92.2703
Functional classRural Minor Collector

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
Deck5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
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 inspectionApril 2024
Inspection intervalevery 12 months
Operating statusPosted for load restriction
ScourFoundations stable; scour above top of footing
Structural evaluation4: Meets minimum tolerable limits to be left in place as is
Deck geometry4: Meets minimum tolerable limits to be left in place as is
Waterway adequacy7: Better than present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating23.1 US tons
Inventory rating15.8 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel
DeckWood or timber
Main spans2
Design loadUnknown
Structure length61 ft (18.6 m)
Longest span30 ft (9.1 m)
Deck width20 ft (6.1 m)
Roadway width20 ft (6 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic15 (2022)
Projected traffic15 by 2044
Trucks0%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed6.2 mi (10 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 proposedReplacement because of substandard load-carrying capacity or roadway geometry
Estimated improvement cost—
NavigationNo navigation control on waterway

Frequently asked questions

When was FM 20th ST over Br Upper Iowa River built?

It was built in 1951, making it 74 years old in 2025.

What condition is FM 20th ST over Br Upper Iowa River 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 April 2024.

How much traffic does FM 20th ST over Br Upper Iowa River carry?

About 15 vehicles per day (2022 count).

How long is FM 20th ST over Br Upper Iowa River?

The structure is 61 ft (18.6 m) long with a longest span of 30 ft (9.1 m) and a deck 20 ft wide.

Who owns FM 20th ST over Br Upper Iowa River?

It is owned by the County Highway Agency.