US Bridges

300th Ave SE over Patterson Creek

Fair

King County, Washington · 0.1 MI S of SR-202 · Structure no. 080714000000000

Built
1951
74 years old, rebuilt 1973
Condition
Fair
inspected September 2024
Type
Stringer/Multi-beam or Girder
Wood or Timber
Length
21 ft
1 main span
Daily traffic
10
2019 count
Owner
County
County Highway Agency

About this bridge

300th Ave SE over Patterson Creek is a wood or timber stringer/multi-beam or girder carrying 300th Ave SE over Patterson Creek in King County, Washington. It was built in 1951 and reconstructed in 1973, so it is 74 years old, older than the Washington average of 49.8 years.

The most recent inspection reported to the Federal Highway Administration rates it in fair condition with a lowest component rating of 6 out of 9. The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.

It carries about 10 vehicles a day, roughly 10% of them trucks, projected to reach 120 by 2039. The structure is 21 ft (6.4 m) long and 20 ft wide. If it were closed, the detour would be 98.8 mi (159 km).

Location

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Carries300th Ave SE
CrossesPatterson Creek
Location0.1 MI S of SR-202
RouteCounty Highway 83510
CountyKing County
StateWashington
Coordinates47.58175, -121.94278
Functional classRural Local

Condition and inspection

Fair

The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.

ComponentRatingMeaning
Deck6 SatisfactoryStructural elements show some minor deterioration.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionSeptember 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourUnknown foundation; not evaluated for scour
Structural evaluation6: Equal to present minimum criteria
Deck geometry4: Meets minimum tolerable limits to be left in place as is
Waterway adequacy6: Equal to present minimum criteria
Approach roadway alignment6: Equal to present minimum criteria
Operating rating39 US tons
Inventory rating28 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialWood or Timber
DeckWood or timber
Main spans1
Design loadH 15
Structure length21 ft (6.4 m)
Longest span20 ft (6.1 m)
Deck width20 ft (6.1 m)
Roadway width19 ft (5.8 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic10 (2019)
Projected traffic120 by 2039
Trucks10%
Lanes on structure1
Traffic directionOne-lane bridge for two-way traffic
CarriesHighway
CrossesWaterway
Detour if closed98.8 mi (159 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$766,000 (2022 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was 300th Ave SE over Patterson Creek built?

It was built in 1951, making it 74 years old in 2025. It was reconstructed in 1973.

What condition is 300th Ave SE over Patterson Creek in?

The National Bridge Inventory rates it in fair condition. The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound. The last reported inspection was in September 2024.

How much traffic does 300th Ave SE over Patterson Creek carry?

About 10 vehicles per day (2019 count), of which roughly 10% are trucks.

How long is 300th Ave SE over Patterson Creek?

The structure is 21 ft (6.4 m) long with a longest span of 20 ft (6.1 m) and a deck 20 ft wide.

Who owns 300th Ave SE over Patterson Creek?

It is owned by the County Highway Agency.