Structure I00015127+09361 · Silver Bow County, MT

I 15 over Int Harrison AVE

Carries I 15 over Int Harrison AVE, Butte.

Overall conditionFair

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

How ratings work
Deck7/9 · Good
Superstructure6/9 · Satisfactory
Substructuresets the rating5/9 · Fair
0 failed4 poor6 fair9 excellent

Elevation

Side view, colored by inspection rating
SEMI-TRUCK · 72 FT209 FT OVERALL25 FT0ELEVATION · LENGTHS TO SCALE
Deck 7/9Superstructure 6/9Substructure 5/9 · sets the rating

209 ft end to end, longest span 60 ft: 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.

Built196066 years old
Length209.0 ft63.7 m
Daily traffic7,009counted 2023
Last inspectedSeptember 2023every 24 months

Location

StateMontana
CountySilver Bow
LocationButte
CarriesI 15
CrossesInt Harrison AVE
Coordinates45.98422, -112.50817

Physical Characteristics

MaterialPrestressed Concrete
DesignStringer/Multi-beam
Total Length209.0 ft (63.7 m)
Max Span60.0 ft (18.3 m)
Deck Width31.5 ft (9.6 m)
Deck Area611.5 sq m
Main Spans4
Year Built1960

Traffic

Avg Daily Traffic7,009 (2023)
Truck Traffic15%
Lanes On Bridge2
Lanes Under Bridge4

Inspection & Ownership

Last InspectionSeptember 2023
Inspection FrequencyEvery 24 months
OwnerState Highway Agency
Historical SignificanceBridge is not eligible for the National Register
Scour CriticalNot applicable
Structure NumberI00015127+09361

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.

Nearby Bridges