US Bridges

20th ST over Iais RR

Good

Poweshiek County, Iowa · 080161702 · Structure no. 000000000293841

Built
2018
7 years old
Condition
Good
inspected December 2022
Type
Stringer/Multi-beam or Girder
Steel
Length
160 ft
3 main spans
Daily traffic
200
2022 count
Owner
County
County Highway Agency

About this bridge

20th ST over Iais RR is a steel stringer/multi-beam or girder carrying 20th ST over Iais RR in Poweshiek County, Iowa. It was built in 2018, so it is 7 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 200 vehicles a day, roughly 20% of them trucks, projected to reach 200 by 2043. The structure is 160 ft (48.8 m) long and 25 ft wide. If it were closed, the detour would be 1.9 mi (3 km).

Location

Open in Google Maps
Carries20th ST
CrossesIais RR
Location080161702
RouteCounty Highway 0
CountyPoweshiek County
StateIowa
Coordinates41.73674, -92.74657
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.
Last inspectionDecember 2022
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourBridge not over waterway
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Deck geometry4: Meets minimum tolerable limits to be left in place as is
Approach roadway alignment5: Somewhat better than minimum adequacy to tolerate being left in place as is
Operating rating26.8 US tons
Inventory rating20.1 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel
DeckWood or timber
Main spans3
Design loadUnknown
Structure length160 ft (48.8 m)
Longest span79 ft (24.1 m)
Deck width25 ft (7.6 m)
Roadway width23 ft (7 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic200 (2022)
Projected traffic200 by 2043
Trucks20%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesRailroad
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—
NavigationNot applicable (no waterway)

Frequently asked questions

When was 20th ST over Iais RR built?

It was built in 2018, making it 7 years old in 2025.

What condition is 20th ST over Iais RR 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 December 2022.

How much traffic does 20th ST over Iais RR carry?

About 200 vehicles per day (2022 count), of which roughly 20% are trucks.

How long is 20th ST over Iais RR?

The structure is 160 ft (48.8 m) long with a longest span of 79 ft (24.1 m) and a deck 25 ft wide.

Who owns 20th ST over Iais RR?

It is owned by the County Highway Agency.