US Bridges

Csah 46 over Maple River

Fair

Blue Earth County, Minnesota · 1.2 MI E of JCT Csah 7 · Structure no. 07521

Built
1971
54 years old
Condition
Fair
inspected December 2024
Type
Channel Beam
Prestressed Concrete
Length
93 ft
3 main spans
Daily traffic
248
2021 count
Owner
County
County Highway Agency

About this bridge

Csah 46 over Maple River is a prestressed concrete channel beam carrying Csah 46 over Maple River in Blue Earth County, Minnesota. It was built in 1971, so it is 54 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 248 vehicles a day, projected to reach 380 by 2041. The structure is 93 ft (28.4 m) long and 38 ft wide. If it were closed, the detour would be 3.1 mi (5 km).

Location

Open in Google Maps
CarriesCsah 46
CrossesMaple River
Location1.2 MI E of JCT Csah 7
RouteCounty Highway 46
CountyBlue Earth County
StateMinnesota
Coordinates43.84819, -93.93891
Functional classRural Major Collector

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.
Superstructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Substructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Channel and channel protection7 GoodSome minor problems.
Last inspectionDecember 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 rating72.4 US tons
Inventory rating43.2 US tons

Structure

Structure typeChannel Beam
MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans3
Design loadHS 20
Structure length93 ft (28.4 m)
Longest span31 ft (9.5 m)
Deck width38 ft (11.6 m)
Roadway width34 ft (10.3 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic248 (2021)
Projected traffic380 by 2041
Trucks—
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed3.1 mi (5 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 Csah 46 over Maple River built?

It was built in 1971, making it 54 years old in 2025.

What condition is Csah 46 over Maple 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 December 2024.

How much traffic does Csah 46 over Maple River carry?

About 248 vehicles per day (2021 count).

How long is Csah 46 over Maple River?

The structure is 93 ft (28.4 m) long with a longest span of 31 ft (9.5 m) and a deck 38 ft wide.

Who owns Csah 46 over Maple River?

It is owned by the County Highway Agency.