US Bridges

US 61 over Muskrat Lake

Fair

Louisa County, Iowa · 4.6 Mi. S of S Jct. Ia 92 · Structure no. 000000000034001

Built
1985
40 years old
Condition
Fair
inspected April 2024
Type
Stringer/Multi-beam or Girder
Prestressed Concrete
Length
307 ft
6 main spans
Daily traffic
4,950
2022 count
Owner
State
State Highway Agency

About this bridge

US 61 over Muskrat Lake is a prestressed concrete stringer/multi-beam or girder carrying US 61 over Muskrat Lake in Louisa County, Iowa. It was built in 1985, so it is 40 years old, younger 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 4,950 vehicles a day, roughly 17% of them trucks, projected to reach 4,950 by 2042. The structure is 307 ft (93.6 m) long and 48 ft wide. If it were closed, the detour would be 16.2 mi (26 km).

Location

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CarriesUS 61
CrossesMuskrat Lake
Location4.6 Mi. S of S Jct. Ia 92
RouteU.S. Route 61
CountyLouisa County
StateIowa
Coordinates41.20649, -91.19802
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 protection8 Very GoodNo problems noted.
Last inspectionApril 2024
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 adequacy7: Better than present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating90.8 US tons
Inventory rating35.6 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans6
Design loadHS 20
Structure length307 ft (93.6 m)
Longest span57 ft (17.4 m)
Deck width48 ft (14.5 m)
Roadway width44 ft (13.4 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic4,950 (2022)
Projected traffic4,950 by 2042
Trucks17%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed16.2 mi (26 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 61 over Muskrat Lake built?

It was built in 1985, making it 40 years old in 2025.

What condition is US 61 over Muskrat Lake 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 April 2024.

How much traffic does US 61 over Muskrat Lake carry?

About 4,950 vehicles per day (2022 count), of which roughly 17% are trucks.

How long is US 61 over Muskrat Lake?

The structure is 307 ft (93.6 m) long with a longest span of 57 ft (17.4 m) and a deck 48 ft wide.

Who owns US 61 over Muskrat Lake?

It is owned by the State Highway Agency.