NB I-35 over CO RD D-25

Fair

Hamilton County, Iowa · At Junction With SR D25 · Structure no. 000000000602530

Built: 1974; 51 years old
Condition: Fair; inspected May 2024
Type: Slab; Concrete Continuous
Length: 143 ft; 3 main spans
Daily traffic: 8,250; 2023 count
Owner: State; State Highway Agency

About this bridge

NB I-35 over CO RD D-25 is a concrete continuous slab carrying NB I-35 over CO RD D-25 in Hamilton County, Iowa. It was built in 1974, so it is 51 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 8,250 vehicles a day, roughly 27% of them trucks, projected to reach 8,250 by 2043. The structure is 143 ft (43.6 m) long and 43 ft wide.

Location

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CarriesNB I-35

CrossesCO RD D-25

LocationAt Junction With SR D25

RouteInterstate 35

CountyHamilton County

StateIowa

Coordinates42.47088, -93.56862

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.

Component	Rating	Meaning
Deck	5 Fair	All primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Superstructure	5 Fair	All primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Substructure	6 Satisfactory	Structural elements show some minor deterioration.

Last inspectionMay 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 geometry7: Better than present minimum criteria

Approach roadway alignment8: Equal to present desirable criteria

Operating rating99.8 US tons

Inventory rating83.2 US tons

Structure

Structure typeSlab

MaterialConcrete Continuous

DeckConcrete, cast-in-place

Main spans3

Design loadHS 20

Structure length143 ft (43.6 m)

Longest span56 ft (17.1 m)

Deck width43 ft (13.2 m)

Roadway width40 ft (12.2 m)

Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic8,250 (2023)

Projected traffic8,250 by 2043

Trucks27%

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 NB I-35 over CO RD D-25 built?

It was built in 1974, making it 51 years old in 2025.

What condition is NB I-35 over CO RD D-25 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 2024.

How much traffic does NB I-35 over CO RD D-25 carry?

About 8,250 vehicles per day (2023 count), of which roughly 27% are trucks.

How long is NB I-35 over CO RD D-25?

The structure is 143 ft (43.6 m) long with a longest span of 56 ft (17.1 m) and a deck 43 ft wide.

Who owns NB I-35 over CO RD D-25?

It is owned by the State Highway Agency.