Structure 16257 727 01259 · Wallowa County, OR

Upper Imnaha Road over Imnaha River

Carries Upper Imnaha Road over Imnaha River, 12.6 Mi S Of HWY 350.

Overall conditionFair

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

How ratings work
Decksets the rating6/9 · Satisfactory
Superstructure8/9 · Very 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
CAR · 15 FT114 FT OVERALL25 FT0ELEVATION · LENGTHS TO SCALE
Deck 6/9 · sets the ratingSuperstructure 8/9Substructure 6/9 · sets the rating

114 ft end to end. Lengths and the car 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 tee-beam bridge.

Built197848 years old
Length113.8 ft34.7 m
Daily traffic94counted 2020
Last inspectedSeptember 2024every 24 months

Location

StateOregon
CountyWallowa
Location12.6 Mi S Of HWY 350
CarriesUpper Imnaha Road
CrossesImnaha River
Coordinates45.40390, -116.79050

Physical Characteristics

MaterialPrestressed Concrete
DesignTee Beam
Total Length113.8 ft (34.7 m)
Max Span111.9 ft (34.1 m)
Deck Width30.8 ft (9.4 m)
Deck Area326.2 sq m
Main Spans1
Year Built1978

Traffic

Avg Daily Traffic94 (2020)
Truck Traffic5%
Lanes On Bridge2

Inspection & Ownership

Last InspectionSeptember 2024
Inspection FrequencyEvery 24 months
OwnerCounty Highway Agency
Historical SignificanceBridge is not eligible for the National Register
Scour Critical4 — Foundations need monitoring
Structure Number16257 727 01259

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.