US Bridges

SR 105 over Slough

Fair

Pacific County, Washington · 7.6 N JCT US 101 · Structure no. 0006057A0000000

Built
1958
67 years old
Condition
Fair
inspected August 2023
Type
Culvert
Steel
Length
20 ft
2 main spans
Daily traffic
1,099
2023 count
Owner
State
State Highway Agency

About this bridge

SR 105 over Slough is a steel culvert carrying SR 105 over Slough in Pacific County, Washington. It was built in 1958, so it is 67 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 1,099 vehicles a day, roughly 12% of them trucks, projected to reach 1,302 by 2039. The structure is 20 ft (6.1 m) long. If it were closed, the detour would be 98.8 mi (159 km).

Location

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CarriesSR 105
CrossesSlough
Location7.6 N JCT US 101
RouteState Highway 105
CountyPacific County
StateWashington
Coordinates46.72639, -123.85247
Functional classRural Minor Arterial

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 protection8 Very GoodNo problems noted.
Culvert6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionAugust 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation6: Equal to present minimum criteria
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating99 US tons
Inventory rating99 US tons

Structure

Structure typeCulvert
MaterialSteel
DeckNot applicable
Main spans2
Design loadUnknown
Structure length20 ft (6.1 m)
Longest span8 ft (2.4 m)
Deck width0 ft (0 m)
Roadway width0 ft (0 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic1,099 (2023)
Projected traffic1,302 by 2039
Trucks12%
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

OwnerState Highway Agency
Maintained byState Highway Agency
Historic statusHistorical significance not determinable at this time
Work proposedRehabilitation because of general structure deterioration or inadequate strength
Estimated improvement cost$323,000 (2022 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was SR 105 over Slough built?

It was built in 1958, making it 67 years old in 2025.

What condition is SR 105 over Slough 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 2023.

How much traffic does SR 105 over Slough carry?

About 1,099 vehicles per day (2023 count), of which roughly 12% are trucks.

How long is SR 105 over Slough?

The structure is 20 ft (6.1 m) long with a longest span of 8 ft (2.4 m).

Who owns SR 105 over Slough?

It is owned by the State Highway Agency.