US Bridges

I-35 NB over 13th ST

Fair

Story County, Iowa · 1.8 Miles N of JCT US 30 · Structure no. 000000000049270

Built
1966
59 years old
Condition
Fair
inspected November 2023
Type
Stringer/Multi-beam or Girder
Prestressed Concrete
Length
162 ft
3 main spans
Daily traffic
14,250
2023 count
Owner
State
State Highway Agency

About this bridge

I-35 NB over 13th ST is a prestressed concrete stringer/multi-beam or girder carrying I-35 NB over 13th ST in Story County, Iowa. It was built in 1966, so it is 59 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 14,250 vehicles a day, roughly 25% of them trucks, projected to reach 14,250 by 2043. The structure is 162 ft (49.4 m) long and 42 ft wide.

Location

Open in Google Maps
CarriesI-35 NB
Crosses13th ST
Location1.8 Miles N of JCT US 30
RouteInterstate 35
CountyStory County
StateIowa
Coordinates42.03432, -93.57035
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.
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 inspectionNovember 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 geometry6: Equal to present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating91.3 US tons
Inventory rating40.1 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans3
Design loadHS 20
Structure length162 ft (49.4 m)
Longest span72 ft (21.9 m)
Deck width42 ft (12.9 m)
Roadway width39 ft (11.9 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic14,250 (2023)
Projected traffic14,250 by 2043
Trucks25%
Lanes on structure2
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 I-35 NB over 13th ST built?

It was built in 1966, making it 59 years old in 2025.

What condition is I-35 NB over 13th ST 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 November 2023.

How much traffic does I-35 NB over 13th ST carry?

About 14,250 vehicles per day (2023 count), of which roughly 25% are trucks.

How long is I-35 NB over 13th ST?

The structure is 162 ft (49.4 m) long with a longest span of 72 ft (21.9 m) and a deck 42 ft wide.

Who owns I-35 NB over 13th ST?

It is owned by the State Highway Agency.