US Bridges

SR 529 over Ebey Slough

Good

Snohomish County, Washington · 0.2 N JCT I-5 · Structure no. 0017948A0000000

Built
2012
13 years old
Condition
Good
inspected April 2023
Type
Stringer/Multi-beam or Girder
Steel Continuous
Length
680 ft
4 main spans
Daily traffic
16,475
2023 count
Owner
State
State Highway Agency

About this bridge

SR 529 over Ebey Slough is a steel continuous stringer/multi-beam or girder carrying SR 529 over Ebey Slough in Snohomish County, Washington. It was built in 2012, so it is 13 years old, younger than the Washington average of 49.8 years.

The most recent inspection reported to the Federal Highway Administration rates it in good condition with a lowest component rating of 8 out of 9. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

It carries about 16,475 vehicles a day, roughly 6% of them trucks, projected to reach 24,469 by 2039. The structure is 680 ft (207.3 m) long and 72 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

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CarriesSR 529
CrossesEbey Slough
Location0.2 N JCT I-5
RouteState Highway 529
CountySnohomish County
StateWashington
Coordinates48.04522, -122.17925
Functional classUrban Other Principal Arterial

Condition and inspection

Good

All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

ComponentRatingMeaning
Deck8 Very GoodNo problems noted.
Superstructure8 Very GoodNo problems noted.
Substructure8 Very GoodNo problems noted.
Channel and channel protection8 Very GoodNo problems noted.
Last inspectionApril 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation8: Equal to present desirable criteria
Deck geometry5: Somewhat better than minimum adequacy to tolerate being left in place as is
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating53.9 US tons
Inventory rating41.8 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel Continuous
DeckConcrete, cast-in-place
Main spans4
Design loadHL 93
Structure length680 ft (207.3 m)
Longest span235 ft (71.6 m)
Deck width72 ft (21.9 m)
Roadway width58 ft (17.7 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic16,475 (2023)
Projected traffic24,469 by 2039
Trucks6%
Lanes on structure4
Traffic directionTwo-way traffic
CarriesHighway and pedestrian
CrossesWaterway
Detour if closed1.2 mi (2 km)
TollOn a free road
National Highway SystemYes

Ownership and planned work

OwnerState Highway Agency
Maintained byState Highway Agency
Historic statusHistorical significance not determinable at this time
Work proposedRehabilitation because of general structure deterioration or inadequate strength
Estimated improvement cost$19.4 million (2022 estimate)
NavigationNavigation control on waterway (bridge permit required)

Frequently asked questions

When was SR 529 over Ebey Slough built?

It was built in 2012, making it 13 years old in 2025.

What condition is SR 529 over Ebey Slough in?

The National Bridge Inventory rates it in good condition. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted. The last reported inspection was in April 2023.

How much traffic does SR 529 over Ebey Slough carry?

About 16,475 vehicles per day (2023 count), of which roughly 6% are trucks.

How long is SR 529 over Ebey Slough?

The structure is 680 ft (207.3 m) long with a longest span of 235 ft (71.6 m) and a deck 72 ft wide.

Who owns SR 529 over Ebey Slough?

It is owned by the State Highway Agency.