Structure S00330015+02001 · Cascade County, MT

Millegan RD over Smith River

Carries Millegan RD over Smith River, 15m SE Ulm.

Overall conditionGood

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

How ratings work
Decksets the rating7/9 · Good
Superstructure8/9 · Very Good
Substructure8/9 · Very Good
Channelnot part of overall6/9 · Satisfactory
0 failed4 poor6 fair9 excellent

Elevation

Side view, colored by inspection rating
SEMI-TRUCK · 72 FT144 FT OVERALL25 FT0ELEVATION · LENGTHS TO SCALE
Deck 7/9 · sets the ratingSuperstructure 8/9Substructure 8/9

144 ft end to end, longest span 71 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.

Built196264 years old
Length144.0 ft43.9 m
Daily traffic294counted 2023
Last inspectedMarch 2023every 24 months

Location

StateMontana
CountyCascade
Location15m SE Ulm
CarriesMillegan RD
CrossesSmith River
Coordinates47.26159, -111.42511

Physical Characteristics

MaterialPrestressed Concrete
DesignStringer/Multi-beam
Total Length144.0 ft (43.9 m)
Max Span70.9 ft (21.6 m)
Deck Width31.2 ft (9.5 m)
Deck Area417.1 sq m
Main Spans2
Year Built1962

Traffic

Avg Daily Traffic294 (2023)
Truck Traffic3%
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 NumberS00330015+02001

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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