US Bridges

6th St.Sw. over US 30

Fair

Linn County, Iowa · 0.3 MI W. of Jct. I-380 · Structure no. 000000000600597

Built
1975
50 years old
Condition
Fair
inspected June 2023
Type
Stringer/Multi-beam or Girder
Prestressed Concrete
Length
281 ft
4 main spans
Daily traffic
10,989
2022 count
Owner
State
State Highway Agency

About this bridge

6th St.Sw. over US 30 is a prestressed concrete stringer/multi-beam or girder carrying 6th St.Sw. 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 10,989 vehicles a day, roughly 14% of them trucks, projected to reach 10,989 by 2042. The structure is 281 ft (85.6 m) long and 79 ft wide. If it were closed, the detour would be 1.9 mi (3 km).

Location

Open in Google Maps
Carries6th St.Sw.
CrossesUS 30
Location0.3 MI W. of Jct. I-380
RouteCity Street 0
CountyLinn County
StateIowa
Coordinates41.92677, -91.67639
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
Deck7 GoodSome minor problems.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure7 GoodSome minor problems.
Last inspectionJune 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 alignment6: Equal to present minimum criteria
Operating rating97.6 US tons
Inventory rating40.1 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans4
Design loadHS 20
Structure length281 ft (85.6 m)
Longest span92 ft (28 m)
Deck width79 ft (24.1 m)
Roadway width71 ft (21.5 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic10,989 (2022)
Projected traffic10,989 by 2042
Trucks14%
Lanes on structure5
Traffic directionTwo-way traffic
CarriesOverpass structure at an interchange
CrossesHighway
Detour if closed1.9 mi (3 km)
TollOn a free road
National Highway SystemNo

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 6th St.Sw. over US 30 built?

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

What condition is 6th St.Sw. 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 June 2023.

How much traffic does 6th St.Sw. over US 30 carry?

About 10,989 vehicles per day (2022 count), of which roughly 14% are trucks.

How long is 6th St.Sw. over US 30?

The structure is 281 ft (85.6 m) long with a longest span of 92 ft (28 m) and a deck 79 ft wide.

Who owns 6th St.Sw. over US 30?

It is owned by the State Highway Agency.