US Bridges

SR 20 over Panther CR

Fair

Whatcom County, Washington · 21.9 E Skagit CO · Structure no. 0008963B0000000

Built
1972
53 years old
Condition
Fair
inspected May 2024
Type
Stringer/Multi-beam or Girder
Prestressed Concrete Continuous
Length
357 ft
3 main spans
Daily traffic
1,173
2023 count
Owner
State
State Highway Agency

About this bridge

SR 20 over Panther CR is a prestressed concrete continuous stringer/multi-beam or girder carrying SR 20 over Panther CR in Whatcom County, Washington. It was built in 1972, so it is 53 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 1,173 vehicles a day, roughly 7% of them trucks, projected to reach 1,734 by 2039. The structure is 357 ft (108.8 m) long and 35 ft wide. If it were closed, the detour would be 98.8 mi (159 km).

Location

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CarriesSR 20
CrossesPanther CR
Location21.9 E Skagit CO
RouteState Highway 20
CountyWhatcom County
StateWashington
Coordinates48.70736, -120.97709
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
Deck7 GoodSome minor problems.
Superstructure7 GoodSome minor problems.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionMay 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations on dry land well above flood water elevations
Structural evaluation6: Equal to present minimum criteria
Deck geometry5: Somewhat better than minimum adequacy to tolerate being left in place as is
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating75 US tons
Inventory rating43 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialPrestressed Concrete Continuous
DeckConcrete, cast-in-place
Main spans3
Design loadHS 20
Structure length357 ft (108.8 m)
Longest span134 ft (40.8 m)
Deck width35 ft (10.8 m)
Roadway width32 ft (9.8 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic1,173 (2023)
Projected traffic1,734 by 2039
Trucks7%
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 statusNot eligible for the National Register of Historic Places
Work proposedRehabilitation because of general structure deterioration or inadequate strength
Estimated improvement cost$6.4 million (2022 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was SR 20 over Panther CR built?

It was built in 1972, making it 53 years old in 2025.

What condition is SR 20 over Panther CR 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 May 2024.

How much traffic does SR 20 over Panther CR carry?

About 1,173 vehicles per day (2023 count), of which roughly 7% are trucks.

How long is SR 20 over Panther CR?

The structure is 357 ft (108.8 m) long with a longest span of 134 ft (40.8 m) and a deck 35 ft wide.

Who owns SR 20 over Panther CR?

It is owned by the State Highway Agency.