Structure L07415004+04001 · Cascade County, MT

Castner Falls RD over Bird Creek 038

Carries Castner Falls RD over Bird Creek 038, 5m E Cascade.

Overall conditionFair

Set by its lowest-rated component: Substructure at 6 of 9.

How ratings work
Deck7/9 · Good
Superstructure7/9 · Good
Substructuresets the rating6/9 · Satisfactory
Channelnot part of overall6/9 · Satisfactory
0 failed4 poor6 fair9 excellent

Elevation

Side view, colored by inspection rating
CAR · 15 FT49 FT OVERALL25 FT0ELEVATION · LENGTHS TO SCALE
Deck 7/9Superstructure 7/9Substructure 6/9 · sets the rating

49 ft end to end, longest span 24 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.

Built1938rebuilt 1970
Length48.9 ft14.9 m
Daily traffic100counted 2025
Last inspectedJanuary 2025every 24 months

Location

StateMontana
CountyCascade
Location5m E Cascade
CarriesCastner Falls RD
CrossesBird Creek 038
Coordinates47.27657, -111.61204

Physical Characteristics

MaterialSteel
DesignStringer/Multi-beam
Total Length48.9 ft (14.9 m)
Max Span24.0 ft (7.3 m)
Deck Width25.9 ft (7.9 m)
Deck Area117.7 sq m
Main Spans2
Year Built1938 (reconstructed 1970)

Traffic

Avg Daily Traffic100 (2025)
Truck Traffic3%
Lanes On Bridge2

Inspection & Ownership

Last InspectionJanuary 2025
Inspection FrequencyEvery 24 months
OwnerCounty Highway Agency
Historical SignificanceBridge is not eligible for the National Register
Scour Critical5 — Stable for scour
Structure NumberL07415004+04001

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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