270th ST over Silver Creek

Good

Clinton County, Iowa · 000000000 · Structure no. 000000000122352

Built: 2009; 16 years old
Condition: Good; inspected June 2024
Type: Slab; Concrete Continuous
Length: 143 ft; 3 main spans
Daily traffic: 220; 2022 count
Owner: County; County Highway Agency

About this bridge

270th ST over Silver Creek is a concrete continuous slab carrying 270th ST over Silver Creek in Clinton County, Iowa. It was built in 2009, so it is 16 years old, younger than the Iowa average of 45.5 years.

The most recent inspection reported to the Federal Highway Administration rates it in good condition with a lowest component rating of 8 out of 9. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

It carries about 220 vehicles a day, projected to reach 220 by 2044. The structure is 143 ft (43.6 m) long and 33 ft wide. If it were closed, the detour would be 5 mi (8 km).

Location

Open in Google Maps

Carries270th ST

CrossesSilver Creek

Location000000000

RouteCounty Highway 0

CountyClinton County

StateIowa

Coordinates41.78587, -90.55431

Functional classRural Minor Collector

Condition and inspection

Good

All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

Component	Rating	Meaning
Deck	8 Very Good	No problems noted.
Superstructure	8 Very Good	No problems noted.
Substructure	8 Very Good	No problems noted.
Channel and channel protection	8 Very Good	No problems noted.

Last inspectionJune 2024

Inspection intervalevery 48 months

Operating statusOpen, no restriction

ScourFoundations stable; scour above top of footing

Structural evaluation8: Equal to present desirable criteria

Deck geometry6: Equal to present minimum criteria

Waterway adequacy8: Equal to present desirable criteria

Approach roadway alignment8: Equal to present desirable criteria

Operating rating94 US tons

Inventory rating50.7 US tons

Structure

Structure typeSlab

MaterialConcrete Continuous

DeckConcrete, cast-in-place

Main spans3

Design loadHS 20

Structure length143 ft (43.6 m)

Longest span55 ft (16.8 m)

Deck width33 ft (10.1 m)

Roadway width30 ft (9.1 m)

Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic220 (2022)

Projected traffic220 by 2044

Trucks0%

Lanes on structure2

Traffic directionTwo-way traffic

CarriesHighway

CrossesWaterway

Detour if closed5 mi (8 km)

TollOn a free road

National Highway SystemNo

Ownership and planned work

OwnerCounty Highway Agency

Maintained byCounty 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 270th ST over Silver Creek built?

It was built in 2009, making it 16 years old in 2025.

What condition is 270th ST over Silver Creek in?

The National Bridge Inventory rates it in good condition. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted. The last reported inspection was in June 2024.

How much traffic does 270th ST over Silver Creek carry?

About 220 vehicles per day (2022 count).

How long is 270th ST over Silver Creek?

The structure is 143 ft (43.6 m) long with a longest span of 55 ft (16.8 m) and a deck 33 ft wide.

Who owns 270th ST over Silver Creek?

It is owned by the County Highway Agency.