Structure S00280012+00001 · Lewis and Clark County, MT

York RD over Missouri River

Carries York RD over Missouri River, 14m NE Helena.

Overall conditionFair

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

How ratings work
Deck7/9 · Good
Superstructure7/9 · Good
Substructuresets the rating6/9 · Satisfactory
Channelnot part of overall8/9 · Very Good
0 failed4 poor6 fair9 excellent

Elevation

Side view, colored by inspection rating
SEMI-TRUCK · 72 FT1,080 FT OVERALL200 FT0ELEVATION · LENGTHS TO SCALE
Deck 7/9Superstructure 7/9Substructure 6/9 · sets the rating

1,080 ft end to end, longest span 120 ft: about 3.0 football fields. 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.

Built198244 years old
Length1079.7 ft329.1 m
Daily traffic551counted 2023
Last inspectedDecember 2023every 24 months

Location

StateMontana
CountyLewis and Clark
Location14m NE Helena
CarriesYork RD
CrossesMissouri River
Coordinates46.71328, -111.80608

Physical Characteristics

MaterialPrestressed Concrete
DesignStringer/Multi-beam
Total Length1079.7 ft (329.1 m)
Max Span120.1 ft (36.6 m)
Deck Width34.4 ft (10.5 m)
Deck Area3455.6 sq m
Main Spans9
Year Built1982

Traffic

Avg Daily Traffic551 (2023)
Truck Traffic15%
Lanes On Bridge2

Inspection & Ownership

Last InspectionDecember 2023
Inspection FrequencyEvery 24 months
OwnerState Highway Agency
Historical SignificanceBridge is not eligible for the National Register
Scour Critical5 — Stable for scour
Structure NumberS00280012+00001

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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