US Bridges

SR 20 over Wiseman Creek

Good

Skagit County, Washington · 4.5 E JCT SR 9 · Structure no. 0003478C0000000

Built
1948
77 years old
Condition
Good
inspected June 2024
Type
Tee Beam
Concrete Continuous
Length
102 ft
3 main spans
Daily traffic
9,612
2023 count
Owner
State
State Highway Agency

About this bridge

SR 20 over Wiseman Creek is a concrete continuous tee beam carrying SR 20 over Wiseman Creek in Skagit County, Washington. It was built in 1948, so it is 77 years old, older than the Washington average of 49.8 years.

The most recent inspection reported to the Federal Highway Administration rates it in good condition with a lowest component rating of 7 out of 9. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

It carries about 9,612 vehicles a day, roughly 9% of them trucks, projected to reach 14,092 by 2039. The structure is 102 ft (31.1 m) long and 40 ft wide. If it were closed, the detour would be 3.1 mi (5 km).

CarriesSR 20
CrossesWiseman Creek
Location4.5 E JCT SR 9
RouteState Highway 20
Coordinates48.52979, -122.13712
Functional classRural Minor Arterial

Condition and inspection

Good

All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

ComponentRatingMeaning
Deck7 GoodSome minor problems.
Superstructure7 GoodSome minor problems.
Substructure7 GoodSome minor problems.
Channel and channel protection7 GoodSome minor problems.
Last inspectionJune 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour within limits of footing or piles
Structural evaluation7: Better than 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 rating91.9 US tons
Inventory rating54 US tons

Structure

Structure typeTee Beam
MaterialConcrete Continuous
DeckConcrete, cast-in-place
Main spans3
Design loadHS 20
Structure length102 ft (31.1 m)
Longest span70 ft (21.3 m)
Deck width40 ft (12.2 m)
Roadway width36 ft (11 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic9,612 (2023)
Projected traffic14,092 by 2039
Trucks9%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed3.1 mi (5 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$1.9 million (2022 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was SR 20 over Wiseman Creek built?

It was built in 1948, making it 77 years old in 2025.

What condition is SR 20 over Wiseman Creek in?

The National Bridge Inventory rates it in good condition. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted. The last reported inspection was in June 2024.

How much traffic does SR 20 over Wiseman Creek carry?

About 9,612 vehicles per day (2023 count), of which roughly 9% are trucks.

How long is SR 20 over Wiseman Creek?

The structure is 102 ft (31.1 m) long with a longest span of 70 ft (21.3 m) and a deck 40 ft wide.

Who owns SR 20 over Wiseman Creek?

It is owned by the State Highway Agency.