US Bridges

I 380 SB over 15th & 16th Ave SW

Fair

Linn County, Iowa · 2.5 Mi. N of Jct. US 30 · Structure no. 000000000607070

Built
1975
50 years old, rebuilt 2018
Condition
Fair
inspected February 2023
Type
Stringer/Multi-beam or Girder
Prestressed Concrete
Length
487 ft
9 main spans
Daily traffic
34,450
2022 count
Owner
State
State Highway Agency

About this bridge

I 380 SB over 15th & 16th Ave SW is a prestressed concrete stringer/multi-beam or girder carrying I 380 SB over 15th & 16th Ave SW in Linn County, Iowa. It was built in 1975 and reconstructed in 2018, 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 34,450 vehicles a day, roughly 12% of them trucks, projected to reach 34,450 by 2043. The structure is 487 ft (148.4 m) long and 55 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

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CarriesI 380 SB
Crosses15th & 16th Ave SW
Location2.5 Mi. N of Jct. US 30
RouteInterstate 380
CountyLinn County
StateIowa
Coordinates41.96287, -91.6709
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
Deck7 GoodSome minor problems.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionFebruary 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourBridge not over waterway
Structural evaluation6: Equal to present minimum criteria
Deck geometry5: Somewhat better than minimum adequacy to tolerate being left in place as is
Approach roadway alignment8: Equal to present desirable criteria
Operating rating68.8 US tons
Inventory rating31.4 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans9
Design loadHS 20
Structure length487 ft (148.4 m)
Longest span65 ft (19.8 m)
Deck width55 ft (16.9 m)
Roadway width52 ft (15.9 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic34,450 (2022)
Projected traffic34,450 by 2043
Trucks12%
Lanes on structure3
Traffic directionOne-way traffic
CarriesHighway
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 15th & 16th Ave SW built?

It was built in 1975, making it 50 years old in 2025. It was reconstructed in 2018.

What condition is I 380 SB over 15th & 16th Ave SW 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 February 2023.

How much traffic does I 380 SB over 15th & 16th Ave SW carry?

About 34,450 vehicles per day (2022 count), of which roughly 12% are trucks.

How long is I 380 SB over 15th & 16th Ave SW?

The structure is 487 ft (148.4 m) long with a longest span of 65 ft (19.8 m) and a deck 55 ft wide.

Who owns I 380 SB over 15th & 16th Ave SW?

It is owned by the State Highway Agency.