US Bridges

Private Road over Granite Creek

Fair

King County, Washington · 5.1 MI N of I-90 · Structure no. 085966000000000

Built
1967
58 years old
Condition
Fair
inspected July 2024
Type
Slab
Concrete
Length
30 ft
1 main span
Daily traffic
25
2020 count
Owner
County
County Highway Agency

About this bridge

Private Road over Granite Creek is a concrete slab carrying Private Road over Granite Creek in King County, Washington. It was built in 1967, so it is 58 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 5 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 25 vehicles a day, projected to reach 40 by 2040. The structure is 30 ft (9.1 m) long and 16 ft wide. If it were closed, the detour would be 98.8 mi (159 km).

Location

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CarriesPrivate Road
CrossesGranite Creek
Location5.1 MI N of I-90
CountyKing County
StateWashington
Coordinates47.49435, -121.63998
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.
Superstructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Substructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Channel and channel protection5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Last inspectionJuly 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourUnknown foundation; not evaluated for scour
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Deck geometry6: Equal to present minimum criteria
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating31.7 US tons
Inventory rating24.7 US tons

Structure

Structure typeSlab
MaterialConcrete
DeckConcrete, precast panels
Main spans1
Design loadHS 20
Structure length30 ft (9.1 m)
Longest span28 ft (8.5 m)
Deck width16 ft (5 m)
Roadway width14 ft (4.3 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic25 (2020)
Projected traffic40 by 2040
Trucks0%
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$988,000 (2022 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was Private Road over Granite Creek built?

It was built in 1967, making it 58 years old in 2025.

What condition is Private Road over Granite 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 July 2024.

How much traffic does Private Road over Granite Creek carry?

About 25 vehicles per day (2020 count).

How long is Private Road over Granite Creek?

The structure is 30 ft (9.1 m) long with a longest span of 28 ft (8.5 m) and a deck 16 ft wide.

Who owns Private Road over Granite Creek?

It is owned by the County Highway Agency.