US Bridges

NB I-380 over 42nd ST

Fair

Linn County, Iowa · 0.5 Mi. S. of Jct. 100 · Structure no. 000000000604700

Built
1981
44 years old
Condition
Fair
inspected November 2024
Type
Stringer/Multi-beam or Girder
Prestressed Concrete
Length
191 ft
3 main spans
Daily traffic
32,850
2022 count
Owner
State
State Highway Agency

About this bridge

NB I-380 over 42nd ST is a prestressed concrete stringer/multi-beam or girder carrying NB I-380 over 42nd ST in Linn County, Iowa. It was built in 1981, so it is 44 years old, younger 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 32,850 vehicles a day, roughly 12% of them trucks, projected to reach 32,850 by 2044. The structure is 191 ft (58.2 m) long and 59 ft wide.

Location

Open in Google Maps
CarriesNB I-380
Crosses42nd ST
Location0.5 Mi. S. of Jct. 100
RouteInterstate 380
CountyLinn County
StateIowa
Coordinates42.02136, -91.66832
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.
Superstructure7 GoodSome minor problems.
Substructure7 GoodSome minor problems.
Last inspectionNovember 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourBridge not over waterway
Structural evaluation7: Better than present minimum criteria
Deck geometry6: Equal to present minimum criteria
Approach roadway alignment7: Better than present minimum criteria
Operating rating61.5 US tons
Inventory rating56.4 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans3
Design loadHS 20 + Mod
Structure length191 ft (58.2 m)
Longest span97 ft (29.6 m)
Deck width59 ft (18 m)
Roadway width56 ft (17.1 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic32,850 (2022)
Projected traffic32,850 by 2044
Trucks12%
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 NB I-380 over 42nd ST built?

It was built in 1981, making it 44 years old in 2025.

What condition is NB I-380 over 42nd 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 2024.

How much traffic does NB I-380 over 42nd ST carry?

About 32,850 vehicles per day (2022 count), of which roughly 12% are trucks.

How long is NB I-380 over 42nd ST?

The structure is 191 ft (58.2 m) long with a longest span of 97 ft (29.6 m) and a deck 59 ft wide.

Who owns NB I-380 over 42nd ST?

It is owned by the State Highway Agency.