Structure L45298000+03001 · Sanders County, MT

Birdland Bay RD over Clark Fork River 001

Carries Birdland Bay RD over Clark Fork River 001, 2m W Thompson Falls.

Overall conditionFair

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

How ratings work
Decksets the rating5/9 · Fair
Superstructure6/9 · Satisfactory
Substructuresets the rating5/9 · Fair
Channelnot part of overall8/9 · Very Good
0 failed4 poor6 fair9 excellent

Elevation

Side view, colored by inspection rating
SEMI-TRUCK · 72 FT310 FT OVERALL50 FT0ELEVATION · LENGTHS TO SCALE
Deck 5/9 · sets the ratingSuperstructure 6/9Substructure 5/9 · sets the rating

310 ft end to end: about 4 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 through truss.

Built192898 years old
Length310.0 ft94.5 m
Daily traffic100counted 2025
Last inspectedJuly 2024every 24 months

Location

StateMontana
CountySanders
Location2m W Thompson Falls
CarriesBirdland Bay RD
CrossesClark Fork River 001
Coordinates47.62152, -115.39159

Physical Characteristics

MaterialSteel
DesignTruss - Thru
Total Length310.0 ft (94.5 m)
Max Span274.9 ft (83.8 m)
Deck Width21.3 ft (6.5 m)
Deck Area614.2 sq m
Main Spans1
Year Built1928

Traffic

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

Inspection & Ownership

Last InspectionJuly 2024
Inspection FrequencyEvery 24 months
OwnerCounty Highway Agency
Historical SignificanceBridge is not eligible for the National Register
Scour Critical8 — Stable, low risk
Structure NumberL45298000+03001

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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