I-5 over Union Slough

Fair Condition58 years old64,989 vehicles/day

Location

StateWashington
CountySnohomish
Location3.3 N Jct US 2
CarriesI-5
CrossesUnion Slough
Coordinates48.02314, -122.17553

Condition Ratings

Overall ConditionFair
Deck6 (Satisfactory)
Superstructure7 (Good)
Substructure6 (Satisfactory)
Channel/Waterway6 (Satisfactory)
Scour Critical8 — Stable, low risk

Physical Characteristics

MaterialPrestressed Concrete
DesignStringer/Multi-beam
Total Length396.0 ft (120.7 m)
Max Span85.0 ft (25.9 m)
Deck Width51.5 ft (15.7 m)
Deck Area1895.0 sq m
Main Spans4
Year Built1968

Traffic

Avg Daily Traffic64,989 (2023)
Truck Traffic6%
Lanes On Bridge3

Inspection & Ownership

Last Inspection623
Inspection FrequencyEvery 24 months
OwnerState Highway Agency
Historical SignificanceHistorical significance is not determined
Structure Number0008226B0000000

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