US Bridges

SB I29 to EB 20 over I 29

Fair

Woodbury County, Iowa · At the JCT of I-29 · Structure no. 000000000600766

Built
1976
49 years old
Condition
Fair
inspected August 2023
Type
Stringer/Multi-beam or Girder
Steel Continuous
Length
569 ft
6 main spans
Daily traffic
5,500
2022 count
Owner
State
State Highway Agency

About this bridge

SB I29 to EB 20 over I 29 is a steel continuous stringer/multi-beam or girder carrying SB I29 to EB 20 over I 29 in Woodbury County, Iowa. It was built in 1976, so it is 49 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.

It carries about 5,500 vehicles a day, roughly 13% of them trucks, projected to reach 5,500 by 2043. The structure is 569 ft (173.4 m) long and 29 ft wide. If it were closed, the detour would be 5 mi (8 km).

Location

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CarriesSB I29 to EB 20
CrossesI 29
LocationAt the JCT of I-29
RouteInterstate 29
CountyWoodbury County
StateIowa
Coordinates42.44522, -96.37668
Functional classUrban Principal Arterial - Interstate

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 inspectionAugust 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourBridge not over waterway
Structural evaluation6: Equal to present minimum criteria
Deck geometry8: Equal to present desirable criteria
Approach roadway alignment6: Equal to present minimum criteria
Operating rating61.2 US tons
Inventory rating37.1 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel Continuous
DeckConcrete, cast-in-place
Main spans6
Design loadHS 20
Structure length569 ft (173.4 m)
Longest span150 ft (45.7 m)
Deck width29 ft (8.8 m)
Roadway width26 ft (7.9 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic5,500 (2022)
Projected traffic5,500 by 2043
Trucks13%
Lanes on structure1
Traffic directionOne-way traffic
CarriesOverpass structure at an interchange
CrossesHighway
Detour if closed5 mi (8 km)
TollOn a free road
National Highway SystemYes

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 SB I29 to EB 20 over I 29 built?

It was built in 1976, making it 49 years old in 2025.

What condition is SB I29 to EB 20 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 August 2023.

How much traffic does SB I29 to EB 20 over I 29 carry?

About 5,500 vehicles per day (2022 count), of which roughly 13% are trucks.

How long is SB I29 to EB 20 over I 29?

The structure is 569 ft (173.4 m) long with a longest span of 150 ft (45.7 m) and a deck 29 ft wide.

Who owns SB I29 to EB 20 over I 29?

It is owned by the State Highway Agency.