US Bridges

Csah 21 over Kettle River

FairPosted for load

Carlton County, Minnesota · 0.8 MI N of JCT Csah 4 · Structure no. 09510

Built
1984
41 years old
Condition
Fair
inspected April 2024
Type
Slab
Wood or Timber
Length
125 ft
4 main spans
Daily traffic
45
2020 count
Owner
County
County Highway Agency

About this bridge

Csah 21 over Kettle River is a wood or timber slab carrying Csah 21 over Kettle River in Carlton County, Minnesota. It was built in 1984, so it is 41 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 6 out of 9. The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound. Its operating status is: posted for load restriction.

It carries about 45 vehicles a day, projected to reach 45 by 2040. The structure is 125 ft (38.1 m) long and 34 ft wide. If it were closed, the detour would be 6.8 mi (11 km).

CarriesCsah 21
CrossesKettle River
Location0.8 MI N of JCT Csah 4
RouteCounty Highway 21
Coordinates46.60411, -92.83012
Functional classRural Minor 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
Deck6 SatisfactoryStructural elements show some minor deterioration.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure7 GoodSome minor problems.
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionApril 2024
Inspection intervalevery 24 months
Operating statusPosted for load restriction
ScourFoundations stable; scour within limits of footing or piles
Structural evaluation6: Equal to present minimum criteria
Deck geometry8: Equal to present desirable criteria
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating51.5 US tons
Inventory rating35.6 US tons

Structure

Structure typeSlab
MaterialWood or Timber
DeckWood or timber
Main spans4
Design loadHS 20
Structure length125 ft (38.1 m)
Longest span31 ft (9.5 m)
Deck width34 ft (10.4 m)
Roadway width32 ft (9.8 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic45 (2020)
Projected traffic45 by 2040
Trucks—
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed6.8 mi (11 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 21 over Kettle River built?

It was built in 1984, making it 41 years old in 2025.

What condition is Csah 21 over Kettle 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 April 2024.

How much traffic does Csah 21 over Kettle River carry?

About 45 vehicles per day (2020 count).

How long is Csah 21 over Kettle River?

The structure is 125 ft (38.1 m) long with a longest span of 31 ft (9.5 m) and a deck 34 ft wide.

Who owns Csah 21 over Kettle River?

It is owned by the County Highway Agency.