Structure P00080046+01121 · Fergus County, MT

S 80 over Arrow Creek

Carries S 80 over Arrow Creek, 17m S Geraldine.

Overall conditionFair

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

How ratings work
Deck6/9 · Satisfactory
Superstructuresets the rating5/9 · Fair
Substructuresets the rating5/9 · Fair
Channelnot part of overall6/9 · Satisfactory
0 failed4 poor6 fair9 excellent

Elevation

Side view, colored by inspection rating
SEMI-TRUCK · 72 FT250 FT OVERALL50 FT0ELEVATION · LENGTHS TO SCALE
Deck 6/9Superstructure 5/9 · sets the ratingSubstructure 5/9 · sets the rating

250 ft end to end, longest span 25 ft: about 3 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.

Built1949rebuilt 1960
Length250.0 ft76.2 m
Daily traffic171counted 2023
Last inspectedSeptember 2024every 24 months

Location

StateMontana
CountyFergus
Location17m S Geraldine
CarriesS 80
CrossesArrow Creek
Coordinates47.41841, -110.16228

Physical Characteristics

MaterialWood or Timber
DesignStringer/Multi-beam
Total Length250.0 ft (76.2 m)
Max Span24.9 ft (7.6 m)
Deck Width25.9 ft (7.9 m)
Deck Area602.0 sq m
Main Spans10
Year Built1949 (reconstructed 1960)

Traffic

Avg Daily Traffic171 (2023)
Truck Traffic16%
Lanes On Bridge2

Inspection & Ownership

Last InspectionSeptember 2024
Inspection FrequencyEvery 24 months
OwnerState Highway Agency
Historical SignificanceBridge is not eligible for the National Register
Scour Critical5 — Stable for scour
Structure NumberP00080046+01121

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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