Structure 518 · Southeast Fairbanks County, AK

Alaska Highway over Johnson River

Carries Alaska Highway over Johnson River, Mile Point 156.1.

Overall conditionPoor

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

How ratings work
Decksets the rating4/9 · Poor
Superstructure5/9 · Fair
Substructure5/9 · Fair
Channelnot part of overall7/9 · Good
0 failed4 poor6 fair9 excellent

Elevation

Side view, colored by inspection rating
SEMI-TRUCK · 72 FT974 FT OVERALL200 FT0ELEVATION · LENGTHS TO SCALE
Deck 4/9 · sets the ratingSuperstructure 5/9Substructure 5/9

974 ft end to end, longest span 200 ft: about 2.7 football fields. 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 through truss.

Built1944rebuilt 1952
Length974.4 ft297 m
Daily traffic180counted 2020
Last inspectedJuly 2024every 24 months

Location

StateAlaska
CountySoutheast Fairbanks
LocationMile Point 156.1
CarriesAlaska Highway
CrossesJohnson River
Coordinates63.70378, -144.64159

Physical Characteristics

MaterialSteel
DesignTruss - Thru
Total Length974.4 ft (297 m)
Max Span200.1 ft (61 m)
Deck Width26.9 ft (8.2 m)
Deck Area2435.4 sq m
Main Spans5
Year Built1944 (reconstructed 1952)

Traffic

Avg Daily Traffic180 (2020)
Truck Traffic28%
Lanes On Bridge2

Inspection & Ownership

Last InspectionJuly 2024
Inspection FrequencyEvery 24 months
OwnerState Highway Agency
Historical SignificanceBridge is not eligible for the National Register
Scour Critical3 — Scour critical
Structure Number0518

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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