US Bridges

Mn 56 over Upper Iowa River

Fair

Mower County, Minnesota · 6.1 MI W of JCT TH 63 · Structure no. 50009

Built
1992
33 years old
Condition
Fair
inspected August 2023
Type
Slab
Concrete Continuous
Length
307 ft
7 main spans
Daily traffic
977
2022 count
Owner
State
State Highway Agency

About this bridge

Mn 56 over Upper Iowa River is a concrete continuous slab carrying Mn 56 over Upper Iowa River in Mower County, Minnesota. It was built in 1992, so it is 33 years old, younger than the Minnesota average of 38.5 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 977 vehicles a day, roughly 26% of them trucks, projected to reach 1,200 by 2042. The structure is 307 ft (93.5 m) long and 46 ft wide. If it were closed, the detour would be 13 mi (21 km).

Location

Open in Google Maps
CarriesMn 56
CrossesUpper Iowa River
Location6.1 MI W of JCT TH 63
RouteState Highway 56
CountyMower County
StateMinnesota
Coordinates43.50759, -92.49094
Functional classRural Minor Arterial

Condition and inspection

Fair

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

ComponentRatingMeaning
Deck7 GoodSome minor problems.
Superstructure7 GoodSome minor problems.
Substructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Channel and channel protection5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Last inspectionAugust 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour within limits of footing or piles
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Deck geometry9: Superior to present desirable criteria
Waterway adequacy9: Superior to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating87.3 US tons
Inventory rating52.4 US tons

Structure

Structure typeSlab
MaterialConcrete Continuous
DeckConcrete, cast-in-place
Main spans7
Design loadHS 25 or greater
Structure length307 ft (93.5 m)
Longest span45 ft (13.7 m)
Deck width46 ft (14.1 m)
Roadway width43 ft (13 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic977 (2022)
Projected traffic1,200 by 2042
Trucks26%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed13 mi (21 km)
TollOn a free road
National Highway SystemNo

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 Mn 56 over Upper Iowa River built?

It was built in 1992, making it 33 years old in 2025.

What condition is Mn 56 over Upper Iowa River 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 August 2023.

How much traffic does Mn 56 over Upper Iowa River carry?

About 977 vehicles per day (2022 count), of which roughly 26% are trucks.

How long is Mn 56 over Upper Iowa River?

The structure is 307 ft (93.5 m) long with a longest span of 45 ft (13.7 m) and a deck 46 ft wide.

Who owns Mn 56 over Upper Iowa River?

It is owned by the State Highway Agency.