Structure I00015130+00262 · Silver Bow County, MT

I 15 over Rr (tracks Not In Use)

Carries I 15 over Rr (tracks Not In Use), Butte.

Overall conditionFair

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

How ratings work
Decksets the rating5/9 · Fair
Superstructure6/9 · Satisfactory
Substructure7/9 · Good
0 failed4 poor6 fair9 excellent

Elevation

Side view, colored by inspection rating
SEMI-TRUCK · 72 FT231 FT OVERALL50 FT0ELEVATION · LENGTHS TO SCALE
Deck 5/9 · sets the ratingSuperstructure 6/9Substructure 7/9

231 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 multi-beam bridge.

Built1966rebuilt 2000
Length231.0 ft70.4 m
Daily traffic2,176counted 2023
Last inspectedJune 2024every 24 months

Location

StateMontana
CountySilver Bow
LocationButte
CarriesI 15
CrossesRr (tracks Not In Use)
Coordinates45.98737, -112.47687

Physical Characteristics

MaterialSteel
DesignStringer/Multi-beam
Total Length231.0 ft (70.4 m)
Max Span77.1 ft (23.5 m)
Deck Width46.9 ft (14.3 m)
Deck Area1006.7 sq m
Main Spans1
Year Built1966 (reconstructed 2000)

Traffic

Avg Daily Traffic2,176 (2023)
Truck Traffic12%
Lanes On Bridge2

Inspection & Ownership

Last InspectionJune 2024
Inspection FrequencyEvery 24 months
OwnerState Highway Agency
Historical SignificanceBridge is not eligible for the National Register
Scour CriticalNot applicable
Structure NumberI00015130+00262

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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