US Bridges

K42 over I-29

FairPosted for load

Monona County, Iowa · 1.7 Mi. N of Ia 175 · Structure no. 000000000037310

Built
1959
66 years old
Condition
Fair
inspected May 2023
Type
Stringer/Multi-beam or Girder
Steel Continuous
Length
255 ft
4 main spans
Daily traffic
390
2022 count
Owner
State
State Highway Agency

About this bridge

K42 over I-29 is a steel continuous stringer/multi-beam or girder carrying K42 over I-29 in Monona County, Iowa. It was built in 1959, so it is 66 years old, older than the Iowa average of 45.5 years.

The most recent inspection reported to the Federal Highway Administration rates it in fair condition with a lowest component rating of 6 out of 9. The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound. Its operating status is: posted for load restriction.

It carries about 390 vehicles a day, roughly 11% of them trucks, projected to reach 390 by 2043. The structure is 255 ft (77.7 m) long and 29 ft wide. If it were closed, the detour would be 1.9 mi (3 km).

Location

Open in Google Maps
CarriesK42
CrossesI-29
Location1.7 Mi. N of Ia 175
RouteCounty Highway 0
CountyMonona County
StateIowa
Coordinates42.04778, -96.14911
Functional classRural Minor Collector

Condition and inspection

Fair

The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.

ComponentRatingMeaning
Deck6 SatisfactoryStructural elements show some minor deterioration.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionMay 2023
Inspection intervalevery 24 months
Operating statusPosted for load restriction
ScourBridge not over waterway
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Deck geometry5: Somewhat better than minimum adequacy to tolerate being left in place as is
Approach roadway alignment5: Somewhat better than minimum adequacy to tolerate being left in place as is
Operating rating31.2 US tons
Inventory rating18.7 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel Continuous
DeckConcrete, cast-in-place
Main spans4
Design loadH 20
Structure length255 ft (77.7 m)
Longest span75 ft (22.9 m)
Deck width29 ft (8.7 m)
Roadway width24 ft (7.3 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic390 (2022)
Projected traffic390 by 2043
Trucks11%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesHighway
Detour if closed1.9 mi (3 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerState Highway Agency
Maintained byState Highway Agency
Historic statusNot eligible for the National Register of Historic Places
Work proposedNone recorded
Estimated improvement cost—
NavigationNot applicable (no waterway)

Frequently asked questions

When was K42 over I-29 built?

It was built in 1959, making it 66 years old in 2025.

What condition is K42 over I-29 in?

The National Bridge Inventory rates it in fair condition. The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound. The last reported inspection was in May 2023.

How much traffic does K42 over I-29 carry?

About 390 vehicles per day (2022 count), of which roughly 11% are trucks.

How long is K42 over I-29?

The structure is 255 ft (77.7 m) long with a longest span of 75 ft (22.9 m) and a deck 29 ft wide.

Who owns K42 over I-29?

It is owned by the State Highway Agency.