US Bridges

Allender RD over Stillwater Creek

FairPosted for load

Cowlitz County, Washington · 0.36 W SR 506 (mp 0.86) · Structure no. 085788000000000

Built
1953
72 years old
Condition
Fair
inspected July 2023
Type
Culvert
Concrete Continuous
Length
30 ft
2 main spans
Daily traffic
20
2023 count
Owner
County
County Highway Agency

About this bridge

Allender RD over Stillwater Creek is a concrete continuous culvert carrying Allender RD over Stillwater Creek in Cowlitz County, Washington. It was built in 1953, so it is 72 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. Its operating status is: posted for load restriction.

It carries about 20 vehicles a day, roughly 5% of them trucks, projected to reach 30 by 2043. The structure is 30 ft (9.1 m) long. If it were closed, the detour would be 98.8 mi (159 km).

Location

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CarriesAllender RD
CrossesStillwater Creek
Location0.36 W SR 506 (mp 0.86)
RouteCounty Highway 28000
CountyCowlitz County
StateWashington
Coordinates46.38472, -123.04917
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
Channel and channel protection5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Culvert6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionJuly 2023
Inspection intervalevery 24 months
Operating statusPosted for load restriction
ScourFoundations stable; scour within limits of footing or piles
Structural evaluation2: Basically intolerable, requiring high priority of replacement
Waterway adequacy6: Equal to present minimum criteria
Approach roadway alignment6: Equal to present minimum criteria
Operating rating9 US tons
Inventory rating5 US tons

Structure

Structure typeCulvert
MaterialConcrete Continuous
DeckNot applicable
Main spans2
Design loadHS 20
Structure length30 ft (9.1 m)
Longest span15 ft (4.6 m)
Deck width0 ft (0 m)
Roadway width0 ft (0 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic20 (2023)
Projected traffic30 by 2043
Trucks5%
Lanes on structure2
Traffic directionTwo-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$1.4 million (2022 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was Allender RD over Stillwater Creek built?

It was built in 1953, making it 72 years old in 2025.

What condition is Allender RD over Stillwater 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 Allender RD over Stillwater Creek carry?

About 20 vehicles per day (2023 count), of which roughly 5% are trucks.

How long is Allender RD over Stillwater Creek?

The structure is 30 ft (9.1 m) long with a longest span of 15 ft (4.6 m).

Who owns Allender RD over Stillwater Creek?

It is owned by the County Highway Agency.