US Bridges

US 30 over Calamus Drainage Ditch

Fair

Clinton County, Iowa · 1.5 Mi. W of SR Y44 · Structure no. 000000000020760

Built
1955
70 years old
Condition
Fair
inspected May 2024
Type
Stringer/Multi-beam or Girder
Steel Continuous
Length
184 ft
3 main spans
Daily traffic
3,430
2022 count
Owner
State
State Highway Agency

About this bridge

US 30 over Calamus Drainage Ditch is a steel continuous stringer/multi-beam or girder carrying US 30 over Calamus Drainage Ditch in Clinton County, Iowa. It was built in 1955, so it is 70 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 3,430 vehicles a day, roughly 16% of them trucks, projected to reach 3,430 by 2042. The structure is 184 ft (56.1 m) long and 34 ft wide. If it were closed, the detour would be 8.1 mi (13 km).

Location

Open in Google Maps
CarriesUS 30
CrossesCalamus Drainage Ditch
Location1.5 Mi. W of SR Y44
RouteU.S. Route 30
CountyClinton County
StateIowa
Coordinates41.82946, -90.79146
Functional classRural Principal Arterial - Other

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.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection7 GoodSome minor problems.
Last inspectionMay 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation6: Equal to present minimum criteria
Deck geometry4: Meets minimum tolerable limits to be left in place as is
Waterway adequacy6: Equal to present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating50.5 US tons
Inventory rating30.3 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel Continuous
DeckConcrete, cast-in-place
Main spans3
Design loadH 20
Structure length184 ft (56.1 m)
Longest span70 ft (21.3 m)
Deck width34 ft (10.4 m)
Roadway width28 ft (8.5 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic3,430 (2022)
Projected traffic3,430 by 2042
Trucks16%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed8.1 mi (13 km)
TollOn a free road
National Highway SystemYes

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—
NavigationNo navigation control on waterway

Frequently asked questions

When was US 30 over Calamus Drainage Ditch built?

It was built in 1955, making it 70 years old in 2025.

What condition is US 30 over Calamus Drainage Ditch 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 US 30 over Calamus Drainage Ditch carry?

About 3,430 vehicles per day (2022 count), of which roughly 16% are trucks.

How long is US 30 over Calamus Drainage Ditch?

The structure is 184 ft (56.1 m) long with a longest span of 70 ft (21.3 m) and a deck 34 ft wide.

Who owns US 30 over Calamus Drainage Ditch?

It is owned by the State Highway Agency.