Structure 1462 · Prince of Wales-Hyder County, AK

Thorne Bay Road over Thorne River

Carries Thorne Bay Road over Thorne River, Mile Point 13.0.

Overall conditionFair

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

How ratings work
Deck7/9 · Good
Superstructuresets the rating6/9 · Satisfactory
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 FT164 FT OVERALL25 FT0ELEVATION · LENGTHS TO SCALE
Deck 7/9Superstructure 6/9 · sets the ratingSubstructure 6/9 · sets the rating

164 ft end to end, longest span 139 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 girder bridge.

Built197551 years old
Length164.0 ft50 m
Daily traffic190counted 2020
Last inspectedJuly 2023every 24 months

Location

StateAlaska
CountyPrince of Wales-Hyder
LocationMile Point 13.0
CarriesThorne Bay Road
CrossesThorne River
Coordinates55.70570, -132.62710

Physical Characteristics

MaterialSteel Continuous
DesignGirder and Floorbeam
Total Length164.0 ft (50 m)
Max Span139.1 ft (42.4 m)
Deck Width24.0 ft (7.3 m)
Deck Area365 sq m
Main Spans3
Year Built1975

Traffic

Avg Daily Traffic190 (2020)
Truck Traffic26%
Lanes On Bridge2

Inspection & Ownership

Last InspectionJuly 2023
Inspection FrequencyEvery 24 months
OwnerState Highway Agency
Historical SignificanceBridge is not eligible for the National Register
Scour Critical8 — Stable, low risk
Structure Number1462

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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