US Bridges

So 30th ST over Harts Mill Creek

Fair

Clinton County, Iowa · 081061502 · Structure no. 000000000002291

Built
1978
47 years old
Condition
Fair
inspected May 2024
Type
Slab
Concrete Continuous
Length
100 ft
3 main spans
Daily traffic
180
2022 count
Owner
City
City or Municipal Highway Agency

About this bridge

So 30th ST over Harts Mill Creek is a concrete continuous slab carrying So 30th ST over Harts Mill Creek in Clinton County, Iowa. It was built in 1978, so it is 47 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 5 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 180 vehicles a day, roughly 8% of them trucks, projected to reach 180 by 2044. The structure is 100 ft (30.5 m) long and 32 ft wide. If it were closed, the detour would be 3.1 mi (5 km).

Location

Open in Google Maps
CarriesSo 30th ST
CrossesHarts Mill Creek
Location081061502
RouteCity Street 0
CountyClinton County
StateIowa
Coordinates41.82559, -90.25759
Functional classUrban Collector

Condition and inspection

Fair

The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.

ComponentRatingMeaning
Deck5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Superstructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Substructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionMay 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Deck geometry6: Equal to present minimum criteria
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment6: Equal to present minimum criteria
Operating rating54.9 US tons
Inventory rating33.1 US tons

Structure

Structure typeSlab
MaterialConcrete Continuous
DeckConcrete, cast-in-place
Main spans3
Design loadH 20
Structure length100 ft (30.5 m)
Longest span39 ft (11.9 m)
Deck width32 ft (9.8 m)
Roadway width30 ft (9.1 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic180 (2022)
Projected traffic180 by 2044
Trucks8%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed3.1 mi (5 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerCity or Municipal Highway Agency
Maintained byCity or Municipal Highway Agency
Historic statusNot eligible for the National Register of Historic Places
Work proposedOther structural work, including hydraulic replacements
Estimated improvement cost$17,000
NavigationNo navigation control on waterway

Frequently asked questions

When was So 30th ST over Harts Mill Creek built?

It was built in 1978, making it 47 years old in 2025.

What condition is So 30th ST over Harts Mill Creek 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 May 2024.

How much traffic does So 30th ST over Harts Mill Creek carry?

About 180 vehicles per day (2022 count), of which roughly 8% are trucks.

How long is So 30th ST over Harts Mill Creek?

The structure is 100 ft (30.5 m) long with a longest span of 39 ft (11.9 m) and a deck 32 ft wide.

Who owns So 30th ST over Harts Mill Creek?

It is owned by the City or Municipal Highway Agency.