US Bridges

SB I-29 over US 30

Fair

Harrison County, Iowa · At Jct. US 30 · Structure no. 000000000028110

Built
1967
58 years old
Condition
Fair
inspected August 2023
Type
Stringer/Multi-beam or Girder
Prestressed Concrete
Length
222 ft
4 main spans
Daily traffic
6,450
2022 count
Owner
State
State Highway Agency

About this bridge

SB I-29 over US 30 is a prestressed concrete stringer/multi-beam or girder carrying SB I-29 over US 30 in Harrison County, Iowa. It was built in 1967, so it is 58 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 5 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 6,450 vehicles a day, roughly 31% of them trucks, projected to reach 6,450 by 2043. The structure is 222 ft (67.7 m) long and 55 ft wide.

Location

Open in Google Maps
CarriesSB I-29
CrossesUS 30
LocationAt Jct. US 30
RouteInterstate 29
CountyHarrison County
StateIowa
Coordinates41.55021, -95.91762
Functional classRural 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
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.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionAugust 2023
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 geometry5: Somewhat better than minimum adequacy to tolerate being left in place as is
Approach roadway alignment8: Equal to present desirable criteria
Operating rating91.9 US tons
Inventory rating40.3 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans4
Design loadHS 20
Structure length222 ft (67.7 m)
Longest span68 ft (20.7 m)
Deck width55 ft (16.7 m)
Roadway width52 ft (15.7 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic6,450 (2022)
Projected traffic6,450 by 2043
Trucks31%
Lanes on structure3
Traffic directionOne-way traffic
CarriesOverpass structure at an interchange
CrossesHighway
Detour if closed—
TollOn a free road
National Highway SystemYes
Strategic Highway NetworkInterstate STRAHNET route

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 I-29 over US 30 built?

It was built in 1967, making it 58 years old in 2025.

What condition is SB I-29 over US 30 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 I-29 over US 30 carry?

About 6,450 vehicles per day (2022 count), of which roughly 31% are trucks.

How long is SB I-29 over US 30?

The structure is 222 ft (67.7 m) long with a longest span of 68 ft (20.7 m) and a deck 55 ft wide.

Who owns SB I-29 over US 30?

It is owned by the State Highway Agency.