US Bridges

County Road 523 over N Fk Thirten Mile CR 064

Fair

Dawson County, Montana · 5M E Bloomfield · Structure no. L11403019+03001

Built
1988
37 years old
Condition
Fair
inspected January 2024
Type
Stringer/Multi-beam or Girder
Steel
Length
39 ft
2 main spans
Daily traffic
26
2023 count
Owner
County
County Highway Agency

About this bridge

County Road 523 over N Fk Thirten Mile CR 064 is a steel stringer/multi-beam or girder carrying County Road 523 over N Fk Thirten Mile CR 064 in Dawson County, Montana. It was built in 1988, so it is 37 years old, younger than the Montana average of 47 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 26 vehicles a day, roughly 3% of them trucks, projected to reach 27 by 2043. The structure is 39 ft (11.9 m) long and 28 ft wide. If it were closed, the detour would be 11.8 mi (19 km).

Location

Open in Google Maps
CarriesCounty Road 523
CrossesN Fk Thirten Mile CR 064
Location5M E Bloomfield
RouteCounty Highway 11403
CountyDawson County
StateMontana
Coordinates47.43197, -104.81169
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.
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 inspectionJanuary 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 geometry6: Equal to present minimum criteria
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating110.1 US tons
Inventory rating110.1 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel
DeckConcrete, cast-in-place
Main spans2
Design loadHS 20
Structure length39 ft (11.9 m)
Longest span20 ft (6.1 m)
Deck width28 ft (8.4 m)
Roadway width26 ft (7.9 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic26 (2023)
Projected traffic27 by 2043
Trucks3%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed11.8 mi (19 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 County Road 523 over N Fk Thirten Mile CR 064 built?

It was built in 1988, making it 37 years old in 2025.

What condition is County Road 523 over N Fk Thirten Mile CR 064 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 January 2024.

How much traffic does County Road 523 over N Fk Thirten Mile CR 064 carry?

About 26 vehicles per day (2023 count), of which roughly 3% are trucks.

How long is County Road 523 over N Fk Thirten Mile CR 064?

The structure is 39 ft (11.9 m) long with a longest span of 20 ft (6.1 m) and a deck 28 ft wide.

Who owns County Road 523 over N Fk Thirten Mile CR 064?

It is owned by the County Highway Agency.