Structure P00022065+06251 · Sheridan County, MT

S 16 over Medicine Lake

Carries S 16 over Medicine Lake, 1m S Medicine Lake.

Overall conditionFair

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

How ratings work
Decksets the rating6/9 · Satisfactory
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 FT161 FT OVERALL25 FT0ELEVATION · LENGTHS TO SCALE
Deck 6/9 · sets the ratingSuperstructure 7/9Substructure 6/9 · sets the rating

161 ft end to end, longest span 35 ft: about 2 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.

Built197551 years old
Length161.1 ft49.1 m
Daily traffic891counted 2023
Last inspectedAugust 2024every 24 months

Location

StateMontana
CountySheridan
Location1m S Medicine Lake
CarriesS 16
CrossesMedicine Lake
Coordinates48.47900, -104.49747

Physical Characteristics

MaterialPrestressed Concrete
DesignStringer/Multi-beam
Total Length161.1 ft (49.1 m)
Max Span35.1 ft (10.7 m)
Deck Width42.3 ft (12.9 m)
Deck Area633.4 sq m
Main Spans5
Year Built1975

Traffic

Avg Daily Traffic891 (2023)
Truck Traffic10%
Lanes On Bridge2

Inspection & Ownership

Last InspectionAugust 2024
Inspection FrequencyEvery 24 months
OwnerState Highway Agency
Historical SignificanceBridge is not eligible for the National Register
Scour Critical5 — Stable for scour
Structure NumberP00022065+06251

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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