Structure C101 · Glacier County, MT

IRR BIA RTE 1 over Two Medicine River

Carries IRR BIA RTE 1 over Two Medicine River, 16 Km South Of Browning.

Overall conditionFair

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

How ratings work
Decksets the rating6/9 · Satisfactory
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 FT358 FT OVERALL50 FT0ELEVATION · LENGTHS TO SCALE
Deck 6/9 · sets the ratingSuperstructure 7/9Substructure 7/9

358 ft end to end, longest span 100 ft: about 5 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.

Built196759 years old
Length357.9 ft109.1 m
Daily traffic1,000counted 2023
Last inspectedSeptember 2023every 24 months

Location

StateMontana
CountyGlacier
Location16 Km South Of Browning
CarriesIRR BIA RTE 1
CrossesTwo Medicine River
Coordinates48.42683, -112.99053

Physical Characteristics

MaterialPrestressed Concrete
DesignStringer/Multi-beam
Total Length357.9 ft (109.1 m)
Max Span100.1 ft (30.5 m)
Deck Width28.9 ft (8.8 m)
Deck Area960.1 sq m
Main Spans4
Year Built1967

Traffic

Avg Daily Traffic1,000 (2023)
Truck Traffic10%
Lanes On Bridge2

Inspection & Ownership

Last InspectionSeptember 2023
Inspection FrequencyEvery 24 months
OwnerBureau of Indian Affairs
Historical SignificanceBridge is not eligible for the National Register
Scour Critical8 — Stable, low risk
Structure Number00000000000C101

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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