US Bridges

US 101 over Skookum CR Np RY

Fair

Mason County, Washington · 0.3 S JCT SR 108 · Structure no. 0006884B0000000

Built
1962
63 years old
Condition
Fair
inspected April 2023
Type
Stringer/Multi-beam or Girder
Prestressed Concrete
Length
240 ft
4 main spans
Daily traffic
12,942
2023 count
Owner
State
State Highway Agency

About this bridge

US 101 over Skookum CR Np RY is a prestressed concrete stringer/multi-beam or girder carrying US 101 over Skookum CR Np RY in Mason 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 12,942 vehicles a day, roughly 7% of them trucks, projected to reach 17,823 by 2039. The structure is 240 ft (73.2 m) long and 35 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

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CarriesUS 101
CrossesSkookum CR Np RY
Location0.3 S JCT SR 108
RouteU.S. Route 101
CountyMason County
StateWashington
Coordinates47.12622, -123.10019
Functional classRural Principal Arterial - Other

Condition and inspection

Fair

The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.

ComponentRatingMeaning
Deck8 Very GoodNo problems noted.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure7 GoodSome minor problems.
Channel and channel protection7 GoodSome minor problems.
Last inspectionApril 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation6: Equal to present minimum criteria
Deck geometry4: Meets minimum tolerable limits to be left in place as is
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating65 US tons
Inventory rating39 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans4
Design loadHS 20
Structure length240 ft (73.2 m)
Longest span72 ft (21.9 m)
Deck width35 ft (10.8 m)
Roadway width32 ft (9.9 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic12,942 (2023)
Projected traffic17,823 by 2039
Trucks7%
Lanes on structure2
Traffic directionOne-way traffic
CarriesHighway
CrossesRailroad and waterway
Detour if closed1.2 mi (2 km)
TollOn a free road
National Highway SystemYes

Ownership and planned work

OwnerState Highway Agency
Maintained byState Highway Agency
Historic statusNot eligible for the National Register of Historic Places
Work proposedRehabilitation because of general structure deterioration or inadequate strength
Estimated improvement cost$4.1 million (2022 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was US 101 over Skookum CR Np RY built?

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

What condition is US 101 over Skookum CR Np RY 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 April 2023.

How much traffic does US 101 over Skookum CR Np RY carry?

About 12,942 vehicles per day (2023 count), of which roughly 7% are trucks.

How long is US 101 over Skookum CR Np RY?

The structure is 240 ft (73.2 m) long with a longest span of 72 ft (21.9 m) and a deck 35 ft wide.

Who owns US 101 over Skookum CR Np RY?

It is owned by the State Highway Agency.