US Bridges

14/16th Ave SE over Duwamish River

Good

King County, Washington · 0.8 MI N of SR-99 · Structure no. 088701000000000

Built
2014
11 years old
Condition
Good
inspected September 2024
Type
Movable - Bascule
Steel
Length
921 ft
1 main span
Daily traffic
16,000
2020 count
Owner
County
County Highway Agency

About this bridge

14/16th Ave SE over Duwamish River is a steel movable - bascule carrying 14/16th Ave SE over Duwamish River in King County, Washington. It was built in 2014, so it is 11 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 16,000 vehicles a day, roughly 13% of them trucks, projected to reach 31,000 by 2040. The structure is 921 ft (280.7 m) long and 71 ft wide. If it were closed, the detour would be 3.7 mi (6 km).

Location

Open in Google Maps
Carries14/16th Ave SE
CrossesDuwamish River
Location0.8 MI N of SR-99
RouteCounty Highway 90113
CountyKing County
StateWashington
Coordinates47.52856, -122.31475
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 inspectionSeptember 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation6: Equal to present minimum 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 rating52.5 US tons
Inventory rating30.3 US tons

Structure

Structure typeMovable - Bascule
MaterialSteel
DeckConcrete, cast-in-place
Main spans1 (+4 approach)
Design loadHL 93
Structure length921 ft (280.7 m)
Longest span198 ft (60.4 m)
Deck width71 ft (21.5 m)
Roadway width55 ft (16.8 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic16,000 (2020)
Projected traffic31,000 by 2040
Trucks13%
Lanes on structure4
Traffic directionTwo-way traffic
CarriesHighway and pedestrian
CrossesHighway and waterway
Detour if closed3.7 mi (6 km)
TollOn a free road
National Highway SystemYes

Ownership and planned work

OwnerCounty Highway Agency
Maintained byCounty Highway Agency
Historic statusListed on the National Register of Historic Places
Work proposedRehabilitation because of general structure deterioration or inadequate strength
Estimated improvement cost$24.5 million (2022 estimate)
NavigationNavigation control on waterway (bridge permit required)

Frequently asked questions

When was 14/16th Ave SE over Duwamish River built?

It was built in 2014, making it 11 years old in 2025.

What condition is 14/16th Ave SE over Duwamish River 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 September 2024.

How much traffic does 14/16th Ave SE over Duwamish River carry?

About 16,000 vehicles per day (2020 count), of which roughly 13% are trucks.

How long is 14/16th Ave SE over Duwamish River?

The structure is 921 ft (280.7 m) long with a longest span of 198 ft (60.4 m) and a deck 71 ft wide.

Who owns 14/16th Ave SE over Duwamish River?

It is owned by the County Highway Agency.