US Bridges

NB Dubuque ST over I 80

Fair

Johnson County, Iowa · At the Jct. of S.R. W66 · Structure no. 000000000032120

Built
1963
62 years old
Condition
Fair
inspected September 2024
Type
Stringer/Multi-beam or Girder
Steel Continuous
Length
240 ft
4 main spans
Daily traffic
3,750
2022 count
Owner
State
State Highway Agency

About this bridge

NB Dubuque ST over I 80 is a steel continuous stringer/multi-beam or girder carrying NB Dubuque ST over I 80 in Johnson County, Iowa. It was built in 1963, so it is 62 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 3,750 vehicles a day, projected to reach 3,750 by 2044. The structure is 240 ft (73.2 m) long and 36 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

Open in Google Maps
CarriesNB Dubuque ST
CrossesI 80
LocationAt the Jct. of S.R. W66
RouteCity Street 0
CountyJohnson County
StateIowa
Coordinates41.6864, -91.53949
Functional classUrban Minor Arterial

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 inspectionSeptember 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourBridge not over waterway
Structural evaluation6: Equal to present minimum criteria
Deck geometry4: Meets minimum tolerable limits to be left in place as is
Approach roadway alignment7: Better than present minimum criteria
Operating rating49.7 US tons
Inventory rating29.8 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel Continuous
DeckConcrete, cast-in-place
Main spans4
Design loadHS 20
Structure length240 ft (73.2 m)
Longest span66 ft (20.1 m)
Deck width36 ft (11 m)
Roadway width30 ft (9.1 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic3,750 (2022)
Projected traffic3,750 by 2044
Trucks0%
Lanes on structure2
Traffic directionOne-way traffic
CarriesOverpass structure at an interchange
CrossesHighway
Detour if closed1.2 mi (2 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerState Highway Agency
Maintained byState Highway Agency
Historic statusPossibly eligible for the National Register; requires further investigation
Work proposedNone recorded
Estimated improvement cost—
NavigationNot applicable (no waterway)

Frequently asked questions

When was NB Dubuque ST over I 80 built?

It was built in 1963, making it 62 years old in 2025.

What condition is NB Dubuque ST over I 80 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 September 2024.

How much traffic does NB Dubuque ST over I 80 carry?

About 3,750 vehicles per day (2022 count).

How long is NB Dubuque ST over I 80?

The structure is 240 ft (73.2 m) long with a longest span of 66 ft (20.1 m) and a deck 36 ft wide.

Who owns NB Dubuque ST over I 80?

It is owned by the State Highway Agency.