US Bridges

Mn 15 over Watonwan River

Fair

Watonwan County, Minnesota · 1.1 MI SW of JCT TH 60 · Structure no. 83017

Built
1975
50 years old
Condition
Fair
inspected August 2024
Type
Stringer/Multi-beam or Girder
Prestressed Concrete
Length
312 ft
3 main spans
Daily traffic
4,150
2018 count
Owner
State
State Highway Agency

About this bridge

Mn 15 over Watonwan River is a prestressed concrete stringer/multi-beam or girder carrying Mn 15 over Watonwan River in Watonwan County, Minnesota. It was built in 1975, so it is 50 years old, older 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 4,150 vehicles a day, roughly 17% of them trucks, projected to reach 39,500 by 2038. The structure is 312 ft (95.1 m) long and 44 ft wide. If it were closed, the detour would be 3.1 mi (5 km).

Location

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CarriesMn 15
CrossesWatonwan River
Location1.1 MI SW of JCT TH 60
RouteState Highway 15
CountyWatonwan County
StateMinnesota
Coordinates44.04171, -94.41097
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.
Substructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionAugust 2024
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 geometry7: Better than present minimum criteria
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating91.4 US tons
Inventory rating36.4 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans3
Design loadHS 20
Structure length312 ft (95.1 m)
Longest span103 ft (31.4 m)
Deck width44 ft (13.5 m)
Roadway width40 ft (12.3 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic4,150 (2018)
Projected traffic39,500 by 2038
Trucks17%
Lanes on structure2
Traffic directionOne-way traffic
CarriesHighway
CrossesWaterway
Detour if closed3.1 mi (5 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 Mn 15 over Watonwan River built?

It was built in 1975, making it 50 years old in 2025.

What condition is Mn 15 over Watonwan 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 2024.

How much traffic does Mn 15 over Watonwan River carry?

About 4,150 vehicles per day (2018 count), of which roughly 17% are trucks.

How long is Mn 15 over Watonwan River?

The structure is 312 ft (95.1 m) long with a longest span of 103 ft (31.4 m) and a deck 44 ft wide.

Who owns Mn 15 over Watonwan River?

It is owned by the State Highway Agency.