US Bridges

Oak Flat Road over Luna Creek

Fair

Klickitat County, Washington · 2.8 S JCT CR 34000 · Structure no. 083386000000000

Built
1981
44 years old
Condition
Fair
inspected July 2023
Type
Slab
Concrete Continuous
Length
52 ft
3 main spans
Daily traffic
32
2021 count
Owner
County
County Highway Agency

About this bridge

Oak Flat Road over Luna Creek is a concrete continuous slab carrying Oak Flat Road over Luna Creek in Klickitat County, Washington. It was built in 1981, so it is 44 years old, younger 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 32 vehicles a day, roughly 14% of them trucks, projected to reach 40 by 2043. The structure is 52 ft (15.8 m) long and 31 ft wide. If it were closed, the detour would be 14.9 mi (24 km).

Location

Open in Google Maps
CarriesOak Flat Road
CrossesLuna Creek
Location2.8 S JCT CR 34000
RouteCounty Highway 34470
CountyKlickitat County
StateWashington
Coordinates45.80681, -120.61893
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
Deck5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection7 GoodSome minor problems.
Last inspectionJuly 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour within limits of footing or piles
Structural evaluation6: Equal to present minimum criteria
Deck geometry7: Better than present minimum criteria
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment6: Equal to present minimum criteria
Operating rating51 US tons
Inventory rating39.2 US tons

Structure

Structure typeSlab
MaterialConcrete Continuous
DeckConcrete, cast-in-place
Main spans3
Design loadHS 20
Structure length52 ft (15.8 m)
Longest span19 ft (5.8 m)
Deck width31 ft (9.4 m)
Roadway width28 ft (8.5 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic32 (2021)
Projected traffic40 by 2043
Trucks14%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed14.9 mi (24 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 proposedOther structural work, including hydraulic replacements
Estimated improvement cost$741,000 (2022 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was Oak Flat Road over Luna Creek built?

It was built in 1981, making it 44 years old in 2025.

What condition is Oak Flat Road over Luna 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 2023.

How much traffic does Oak Flat Road over Luna Creek carry?

About 32 vehicles per day (2021 count), of which roughly 14% are trucks.

How long is Oak Flat Road over Luna Creek?

The structure is 52 ft (15.8 m) long with a longest span of 19 ft (5.8 m) and a deck 31 ft wide.

Who owns Oak Flat Road over Luna Creek?

It is owned by the County Highway Agency.