Structure S00358016+08321 · Pondera County, MT

IRR - S 358 over Two Medicine River

Carries IRR - S 358 over Two Medicine River, 12m S Cut Bank.

Overall conditionPoor

Set by its lowest-rated component: Deck at 4 of 9.

How ratings work
Decksets the rating4/9 · Poor
Superstructure7/9 · Good
Substructure7/9 · Good
Channelnot part of overall7/9 · Good
0 failed4 poor6 fair9 excellent

Elevation

Side view, colored by inspection rating
SEMI-TRUCK · 72 FT318 FT OVERALL50 FT0ELEVATION · LENGTHS TO SCALE
Deck 4/9 · sets the ratingSuperstructure 7/9Substructure 7/9

318 ft end to end, longest span 65 ft: about 4 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.

Built196858 years old
Length317.9 ft96.9 m
Daily traffic243counted 2023
Last inspectedAugust 2023every 24 months

Location

StateMontana
CountyPondera
Location12m S Cut Bank
CarriesIRR - S 358
CrossesTwo Medicine River
Coordinates48.47221, -112.35840

Physical Characteristics

MaterialPrestressed Concrete
DesignStringer/Multi-beam
Total Length317.9 ft (96.9 m)
Max Span65.0 ft (19.8 m)
Deck Width35.8 ft (10.9 m)
Deck Area1056.2 sq m
Main Spans5
Year Built1968

Traffic

Avg Daily Traffic243 (2023)
Truck Traffic9%
Lanes On Bridge2

Inspection & Ownership

Last InspectionAugust 2023
Inspection FrequencyEvery 24 months
OwnerState Highway Agency
Historical SignificanceBridge is not eligible for the National Register
Scour Critical5 — Stable for scour
Structure NumberS00358016+08321

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.