US Bridges

I 35 NB over US 30

Fair

Story County, Iowa · At Junction With US 30 · Structure no. 000000000049210

Built
1964
61 years old
Condition
Fair
inspected January 2024
Type
Stringer/Multi-beam or Girder
Prestressed Concrete
Length
235 ft
4 main spans
Daily traffic
15,000
2023 count
Owner
State
State Highway Agency

About this bridge

I 35 NB over US 30 is a prestressed concrete stringer/multi-beam or girder carrying I 35 NB over US 30 in Story County, Iowa. It was built in 1964, so it is 61 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 15,000 vehicles a day, roughly 23% of them trucks, projected to reach 15,000 by 2043. The structure is 235 ft (71.6 m) long and 46 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

Open in Google Maps
CarriesI 35 NB
CrossesUS 30
LocationAt Junction With US 30
RouteInterstate 35
CountyStory County
StateIowa
Coordinates42.00736, -93.57101
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 inspectionJanuary 2024
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 geometry3: Basically intolerable, requiring high priority of corrective action
Approach roadway alignment6: Equal to present minimum criteria
Operating rating88.7 US tons
Inventory rating36.2 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans4
Design loadHS 20
Structure length235 ft (71.6 m)
Longest span69 ft (21 m)
Deck width46 ft (14 m)
Roadway width40 ft (12.2 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic15,000 (2023)
Projected traffic15,000 by 2043
Trucks23%
Lanes on structure3
Traffic directionOne-way traffic
CarriesOverpass structure at an interchange
CrossesHighway
Detour if closed1.2 mi (2 km)
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 I 35 NB over US 30 built?

It was built in 1964, making it 61 years old in 2025.

What condition is I 35 NB 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 January 2024.

How much traffic does I 35 NB over US 30 carry?

About 15,000 vehicles per day (2023 count), of which roughly 23% are trucks.

How long is I 35 NB over US 30?

The structure is 235 ft (71.6 m) long with a longest span of 69 ft (21 m) and a deck 46 ft wide.

Who owns I 35 NB over US 30?

It is owned by the State Highway Agency.