US Bridges

284th Ave SE over Drainage Ditch

Good

King County, Washington · 800FT N of SE 472nd ST · Structure no. 089532000000000

Built
2023
2 years old
Condition
Good
inspected June 2024
Type
Culvert
Concrete
Length
33 ft
1 main span
Daily traffic
1,600
2024 count
Owner
County
County Highway Agency

About this bridge

284th Ave SE over Drainage Ditch is a concrete culvert carrying 284th Ave SE over Drainage Ditch in King County, Washington. It was built in 2023, so it is 2 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 7 out of 9. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

It carries about 1,600 vehicles a day, roughly 3% of them trucks, projected to reach 2,885 by 2039. The structure is 33 ft (10.1 m) long and 57 ft wide. If it were closed, the detour would be 1.9 mi (3 km).

Carries284th Ave SE
CrossesDrainage Ditch
Location800FT N of SE 472nd ST
RouteCounty Highway 30050
Coordinates47.17978, -121.96339
Functional classRural Minor Collector

Condition and inspection

Good

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

ComponentRatingMeaning
Deck7 GoodSome minor problems.
Channel and channel protection7 GoodSome minor problems.
Culvert7 GoodSome minor problems.
Last inspectionJune 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation7: Better than present minimum criteria
Deck geometry9: Superior to present desirable criteria
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating48.9 US tons
Inventory rating37.8 US tons

Structure

Structure typeCulvert
MaterialConcrete
DeckConcrete, precast panels
Main spans1
Design loadHL 93
Structure length33 ft (10.1 m)
Longest span33 ft (10.1 m)
Deck width57 ft (17.4 m)
Roadway width54 ft (16.5 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic1,600 (2024)
Projected traffic2,885 by 2039
Trucks3%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed1.9 mi (3 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerCounty Highway Agency
Maintained byCounty Highway Agency
Historic statusHistorical significance not determinable at this time
Work proposedReplacement because of substandard load-carrying capacity or roadway geometry
Estimated improvement cost$1.6 million (2022 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was 284th Ave SE over Drainage Ditch built?

It was built in 2023, making it 2 years old in 2025.

What condition is 284th Ave SE over Drainage Ditch 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 June 2024.

How much traffic does 284th Ave SE over Drainage Ditch carry?

About 1,600 vehicles per day (2024 count), of which roughly 3% are trucks.

How long is 284th Ave SE over Drainage Ditch?

The structure is 33 ft (10.1 m) long with a longest span of 33 ft (10.1 m) and a deck 57 ft wide.

Who owns 284th Ave SE over Drainage Ditch?

It is owned by the County Highway Agency.