Structure L51040004+04301 · Toole County, MT

Helsa RD over Sep I 15 012

Carries Helsa RD over Sep I 15 012, 2m N Oilmont.

Overall conditionGood

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

How ratings work
Decksets the rating7/9 · Good
Superstructuresets the rating7/9 · Good
Substructuresets the rating7/9 · Good
0 failed4 poor6 fair9 excellent

Elevation

Side view, colored by inspection rating
SEMI-TRUCK · 72 FT225 FT OVERALL25 FT0ELEVATION · LENGTHS TO SCALE
Deck 7/9Superstructure 7/9Substructure 7/9

225 ft end to end, longest span 110 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.

Built197155 years old
Length224.7 ft68.5 m
Daily traffic100counted 2025
Last inspectedOctober 2023every 24 months

Location

StateMontana
CountyToole
Location2m N Oilmont
CarriesHelsa RD
CrossesSep I 15 012
Coordinates48.76906, -111.86276

Physical Characteristics

MaterialSteel Continuous
DesignStringer/Multi-beam
Total Length224.7 ft (68.5 m)
Max Span109.9 ft (33.5 m)
Deck Width30.2 ft (9.2 m)
Deck Area630.2 sq m
Main Spans2
Year Built1971

Traffic

Avg Daily Traffic100 (2025)
Truck Traffic3%
Lanes On Bridge2
Lanes Under Bridge4

Inspection & Ownership

Last InspectionOctober 2023
Inspection FrequencyEvery 24 months
OwnerState Highway Agency
Historical SignificanceBridge is not eligible for the National Register
Scour CriticalNot applicable
Structure NumberL51040004+04301

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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