Structure P00057062+05331 · Judith Basin County, MT

US 87 over Ross Fork Creek

Carries US 87 over Ross Fork Creek, 3m E Hobson.

Overall conditionGood

Set by its lowest-rated component: Deck and Superstructure and Substructure at 7 of 9.

How ratings work
Decksets the rating7/9 · Good
Superstructuresets the rating7/9 · Good
Substructuresets the rating7/9 · Good
Channelnot part of overall6/9 · Satisfactory
0 failed4 poor6 fair9 excellent

Elevation

Side view, colored by inspection rating
SEMI-TRUCK · 72 FT179 FT OVERALL25 FT0ELEVATION · LENGTHS TO SCALE
Deck 7/9Superstructure 7/9Substructure 7/9

179 ft end to end, longest span 67 ft: about 2 semi-trucks nose to tail. Lengths and the semi-truck 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.

Built197155 years old
Length179.1 ft54.6 m
Daily traffic3,335counted 2023
Last inspectedMarch 2023every 24 months

Location

StateMontana
CountyJudith Basin
Location3m E Hobson
CarriesUS 87
CrossesRoss Fork Creek
Coordinates46.99544, -109.79259

Physical Characteristics

MaterialPrestressed Concrete
DesignStringer/Multi-beam
Total Length179.1 ft (54.6 m)
Max Span66.9 ft (20.4 m)
Deck Width45.9 ft (14 m)
Deck Area764.4 sq m
Main Spans3
Year Built1971

Traffic

Avg Daily Traffic3,335 (2023)
Truck Traffic14%
Lanes On Bridge2

Inspection & Ownership

Last InspectionMarch 2023
Inspection FrequencyEvery 24 months
OwnerState Highway Agency
Historical SignificanceBridge is not eligible for the National Register
Scour Critical5 — Stable for scour
Structure NumberP00057062+05331

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.

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