Structure P00080008+07611 · Chouteau County, MT

S 80 over Boyle-o`hanlon Coulees

Carries S 80 over Boyle-o`hanlon Coulees, 6m SE Fort Benton.

Overall conditionFair

Set by its lowest-rated component: Substructure at 5 of 9.

How ratings work
Deck7/9 · Good
Superstructure7/9 · Good
Substructuresets the rating5/9 · Fair
Channelnot part of overall6/9 · Satisfactory
0 failed4 poor6 fair9 excellent

Elevation

Side view, colored by inspection rating
CAR · 15 FT75 FT OVERALL25 FT0ELEVATION · LENGTHS TO SCALE
Deck 7/9Superstructure 7/9Substructure 5/9 · sets the rating

75 ft end to end, longest span 25 ft. Lengths and the car on the deck are drawn to the same scale. Each part is colored by its latest inspection rating. The inventory records lengths but not heights or the layout of the shorter spans, so those are drawn as typical for a multi-beam bridge.

Built193987 years old
Length75.1 ft22.9 m
Daily traffic479counted 2023
Last inspectedAugust 2023every 24 months

Location

StateMontana
CountyChouteau
Location6m SE Fort Benton
CarriesS 80
CrossesBoyle-o`hanlon Coulees
Coordinates47.78676, -110.55303

Physical Characteristics

MaterialWood or Timber
DesignStringer/Multi-beam
Total Length75.1 ft (22.9 m)
Max Span24.9 ft (7.6 m)
Deck Width26.2 ft (8 m)
Deck Area183.2 sq m
Main Spans3
Year Built1939

Traffic

Avg Daily Traffic479 (2023)
Truck Traffic16%
Lanes On Bridge2

Inspection & Ownership

Last InspectionAugust 2023
Inspection FrequencyEvery 24 months
OwnerState Highway Agency
Historical SignificanceBridge is not eligible for the National Register
Scour Critical5 — Stable for scour
Structure NumberP00080008+07611

How Bridge Ratings Work

Inspectors rate each major part of a bridge (the deck you drive on, the superstructure of beams that holds it up, and the substructure of piers and abutments beneath) on a 0–9 scale. A bridge's overall condition is its lowest of those ratings, so one deteriorated component makes the whole bridge "poor."

0Failed
1Imminent failure
2Critical
3Serious
4Poor
5Fair
6Satisfactory
7Good
8Very good
9Excellent
Good · lowest component 7–9
Fair · lowest component 5–6
Poor · lowest component 0–4

A poor rating is not a closure. It means the bridge is flagged for priority repair or replacement; bridges judged unsafe are closed or posted with weight limits. The waterway (channel) rating is reported, but it does not count toward the overall classification.

Nearby Bridges