US Bridges

I 380 SB over US 30

Fair

Linn County, Iowa · At Jct. of U.S. 30 · Structure no. 000000000607010

Built
1975
50 years old
Condition
Fair
inspected January 2023
Type
Stringer/Multi-beam or Girder
Prestressed Concrete
Length
267 ft
4 main spans
Daily traffic
21,400
2022 count
Owner
State
State Highway Agency

About this bridge

I 380 SB over US 30 is a prestressed concrete stringer/multi-beam or girder carrying I 380 SB over US 30 in Linn County, Iowa. It was built in 1975, so it is 50 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 21,400 vehicles a day, roughly 15% of them trucks, projected to reach 21,400 by 2043. The structure is 267 ft (81.4 m) long and 51 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

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CarriesI 380 SB
CrossesUS 30
LocationAt Jct. of U.S. 30
RouteInterstate 380
CountyLinn County
StateIowa
Coordinates41.92736, -91.67006
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 inspectionJanuary 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourBridge not over waterway
Structural evaluation7: Better than present minimum criteria
Deck geometry9: Superior to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating93 US tons
Inventory rating42.1 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans4
Design loadHS 20
Structure length267 ft (81.4 m)
Longest span92 ft (28 m)
Deck width51 ft (15.5 m)
Roadway width48 ft (14.6 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic21,400 (2022)
Projected traffic21,400 by 2043
Trucks15%
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 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 380 SB over US 30 built?

It was built in 1975, making it 50 years old in 2025.

What condition is I 380 SB 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 2023.

How much traffic does I 380 SB over US 30 carry?

About 21,400 vehicles per day (2022 count), of which roughly 15% are trucks.

How long is I 380 SB over US 30?

The structure is 267 ft (81.4 m) long with a longest span of 92 ft (28 m) and a deck 51 ft wide.

Who owns I 380 SB over US 30?

It is owned by the State Highway Agency.