Structure 61520-00036 · Petroleum County, MT

Road 317 over Drag Creek

Carries Road 317 over Drag Creek, Sect 11 T18n R29e.

Overall conditionPoor

Set by its lowest-rated component: Substructure at 4 of 9.

How ratings work
Deck6/9 · Satisfactory
Superstructure6/9 · Satisfactory
Substructuresets the rating4/9 · Poor
Channelnot part of overall4/9 · Poor
0 failed4 poor6 fair9 excellent

Elevation

Side view, colored by inspection rating
24 FT OVERALL25 FT0ELEVATION · LENGTHS TO SCALE
Deck 6/9Superstructure 6/9Substructure 4/9 · sets the rating

24 ft end to end, longest span 11 ft. Lengths are drawn to scale; at this length a semi-truck would be a speck. 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.

Built196363 years old
Length24.0 ft7.3 m
Daily traffic2counted 2024
Last inspectedAugust 2024every 12 months

Location

StateMontana
CountyPetroleum
LocationSect 11 T18n R29e
CarriesRoad 317
CrossesDrag Creek
Coordinates47.34167, -107.96917

Physical Characteristics

MaterialWood or Timber
DesignStringer/Multi-beam
Total Length24.0 ft (7.3 m)
Max Span11.2 ft (3.4 m)
Deck Width12.1 ft (3.7 m)
Deck Area27.0 sq m
Main Spans2
Year Built1963

Traffic

Avg Daily Traffic2 (2024)
Lanes On Bridge1

Inspection & Ownership

Last InspectionAugust 2024
Inspection FrequencyEvery 12 months
OwnerCode 63
Historical SignificanceBridge is not eligible for the National Register
Scour Critical3 — Scour critical
Structure Number000061520-00036

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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