US Bridges

NB US 61 over Silver Creek

Fair

Clinton County, Iowa · 0.9 Mi. N of N JCT US 30 · Structure no. 000000000602840

Built
1974
51 years old
Condition
Fair
inspected July 2023
Type
Stringer/Multi-beam or Girder
Prestressed Concrete
Length
209 ft
3 main spans
Daily traffic
6,350
2022 count
Owner
State
State Highway Agency

About this bridge

NB US 61 over Silver Creek is a prestressed concrete stringer/multi-beam or girder carrying NB US 61 over Silver Creek in Clinton County, Iowa. It was built in 1974, so it is 51 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 6,350 vehicles a day, roughly 16% of them trucks, projected to reach 6,350 by 2043. The structure is 209 ft (63.7 m) long and 43 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

Open in Google Maps
CarriesNB US 61
CrossesSilver Creek
Location0.9 Mi. N of N JCT US 30
RouteU.S. Route 61
CountyClinton County
StateIowa
Coordinates41.83884, -90.56873
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.
Superstructure7 GoodSome minor problems.
Substructure7 GoodSome minor problems.
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionJuly 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour within limits of footing or piles
Structural evaluation7: Better than present minimum criteria
Deck geometry7: Better than present minimum criteria
Waterway adequacy6: Equal to present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating74.1 US tons
Inventory rating41.8 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans3
Design loadHS 20
Structure length209 ft (63.7 m)
Longest span73 ft (22.3 m)
Deck width43 ft (13.2 m)
Roadway width40 ft (12.2 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic6,350 (2022)
Projected traffic6,350 by 2043
Trucks16%
Lanes on structure2
Traffic directionOne-way traffic
CarriesHighway
CrossesWaterway
Detour if closed1.2 mi (2 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 NB US 61 over Silver Creek built?

It was built in 1974, making it 51 years old in 2025.

What condition is NB US 61 over Silver 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 July 2023.

How much traffic does NB US 61 over Silver Creek carry?

About 6,350 vehicles per day (2022 count), of which roughly 16% are trucks.

How long is NB US 61 over Silver Creek?

The structure is 209 ft (63.7 m) long with a longest span of 73 ft (22.3 m) and a deck 43 ft wide.

Who owns NB US 61 over Silver Creek?

It is owned by the State Highway Agency.