US Bridges

Diablo Access RD over Diablo Gorge

Fair

King County, Washington · Diablo Access Road · Structure no. 087463000000000

Built
1962
63 years old
Condition
Fair
inspected August 2022
Type
Girder and Floorbeam System
Steel
Length
60 ft
1 main span
Daily traffic
220
2022 count
Owner
Local
Other Local Agency

About this bridge

Diablo Access RD over Diablo Gorge is a steel girder and floorbeam system carrying Diablo Access RD over Diablo Gorge in King County, Washington. It was built in 1962, so it is 63 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 220 vehicles a day, roughly 15% of them trucks, projected to reach 300 by 2042. The structure is 60 ft (18.3 m) long and 20 ft wide.

Location

Open in Google Maps
CarriesDiablo Access RD
CrossesDiablo Gorge
LocationDiablo Access Road
CountyKing County
StateWashington
Coordinates48.71231, -121.13392
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.
Last inspectionAugust 2022
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourBridge not over waterway
Structural evaluation6: Equal to present minimum criteria
Deck geometry3: Basically intolerable, requiring high priority of corrective action
Approach roadway alignment6: Equal to present minimum criteria
Operating rating87 US tons
Inventory rating52 US tons

Structure

Structure typeGirder and Floorbeam System
MaterialSteel
DeckConcrete, cast-in-place
Main spans1
Design loadUnknown
Structure length60 ft (18.3 m)
Longest span59 ft (18 m)
Deck width20 ft (6 m)
Roadway width18 ft (5.5 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic220 (2022)
Projected traffic300 by 2042
Trucks15%
Lanes on structure1
Traffic directionOne-lane bridge for two-way traffic
CarriesHighway
CrossesOther
Detour if closed—
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerOther Local Agency
Maintained byOther Local Agency
Historic statusHistorical significance not determinable at this time
Work proposedDeck rehabilitation with only incidental widening
Estimated improvement cost$570,000 (2022 estimate)
NavigationNot applicable (no waterway)

Frequently asked questions

When was Diablo Access RD over Diablo Gorge built?

It was built in 1962, making it 63 years old in 2025.

What condition is Diablo Access RD over Diablo Gorge 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 August 2022.

How much traffic does Diablo Access RD over Diablo Gorge carry?

About 220 vehicles per day (2022 count), of which roughly 15% are trucks.

How long is Diablo Access RD over Diablo Gorge?

The structure is 60 ft (18.3 m) long with a longest span of 59 ft (18 m) and a deck 20 ft wide.

Who owns Diablo Access RD over Diablo Gorge?

It is owned by the Other Local Agency.