Structure 2 0089 · Siskiyou County, CA

Interstate 5 over Dunsmuir AVE

Carries Interstate 5 over Dunsmuir AVE, 02-sis-005-2.51-dmr.

Overall conditionFair

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

How ratings work
Decksets the rating6/9 · Satisfactory
Superstructure8/9 · Very Good
Substructure7/9 · Good
0 failed4 poor6 fair9 excellent

Elevation

Side view, colored by inspection rating
CAR · 15 FT45 FT OVERALL25 FT0ELEVATION · LENGTHS TO SCALE
Deck 6/9 · sets the ratingSuperstructure 8/9Substructure 7/9

45 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.

Built196066 years old
Length44.6 ft13.6 m
Daily traffic18,000counted 2024
Last inspectedJuly 2024every 24 months

Location

StateCalifornia
CountySiskiyou
Location02-sis-005-2.51-dmr
CarriesInterstate 5
CrossesDunsmuir AVE
Coordinates41.21770, -122.27449

Physical Characteristics

MaterialConcrete
DesignTee Beam
Total Length44.6 ft (13.6 m)
Max Span41.7 ft (12.7 m)
Deck Width84.3 ft (25.7 m)
Deck Area349.5 sq m
Main Spans1
Year Built1960

Traffic

Avg Daily Traffic18,000 (2024)
Truck Traffic28%
Lanes On Bridge4
Lanes Under Bridge2

Inspection & Ownership

Last InspectionJuly 2024
Inspection FrequencyEvery 24 months
OwnerState Highway Agency
Historical SignificanceBridge is not eligible for the National Register
Scour CriticalNot applicable
Structure Number02 0089

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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