Structure L47017000+01001 · Silver Bow County, MT

Pumphouse RD over Big Hole River 009

Carries Pumphouse RD over Big Hole River 009, 3m W Divide.

Overall conditionFair

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

How ratings work
Deck7/9 · Good
Superstructuresets the rating6/9 · Satisfactory
Substructure7/9 · Good
Channelnot part of overall7/9 · Good
0 failed4 poor6 fair9 excellent

Elevation

Side view, colored by inspection rating
SEMI-TRUCK · 72 FT232 FT OVERALL50 FT0ELEVATION · LENGTHS TO SCALE
Deck 7/9Superstructure 6/9 · sets the ratingSubstructure 7/9

232 ft end to end: 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 through truss.

Built1914rebuilt 2015
Length232.0 ft70.7 m
Daily traffic100counted 2025
Last inspectedJuly 2024every 24 months

Location

StateMontana
CountySilver Bow
Location3m W Divide
CarriesPumphouse RD
CrossesBig Hole River 009
Coordinates45.75972, -112.80165

Physical Characteristics

MaterialSteel
DesignTruss - Thru
Total Length232.0 ft (70.7 m)
Max Span154.9 ft (47.2 m)
Deck Width15.7 ft (4.8 m)
Deck Area339.4 sq m
Main Spans1
Year Built1914 (reconstructed 2015)

Traffic

Avg Daily Traffic100 (2025)
Truck Traffic3%
Lanes On Bridge1

Inspection & Ownership

Last InspectionJuly 2024
Inspection FrequencyEvery 24 months
OwnerCounty Highway Agency
Historical SignificanceBridge is not eligible for the National Register
Scour Critical5 — Stable for scour
Structure NumberL47017000+01001

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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