US Bridges

SR 11 over I-5

Fair

Skagit County, Washington · JCT I-5 · Structure no. 0006011A0000000

Built
1959
66 years old
Condition
Fair
inspected May 2023
Type
Stringer/Multi-beam or Girder
Prestressed Concrete
Length
288 ft
4 main spans
Daily traffic
10,241
2023 count
Owner
State
State Highway Agency

About this bridge

SR 11 over I-5 is a prestressed concrete stringer/multi-beam or girder carrying SR 11 over I-5 in Skagit County, Washington. It was built in 1959, so it is 66 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 10,241 vehicles a day, roughly 9% of them trucks, projected to reach 15,295 by 2039. The structure is 288 ft (87.8 m) long and 34 ft wide. If it were closed, the detour would be 5 mi (8 km).

Location

Open in Google Maps
CarriesSR 11
CrossesI-5
LocationJCT I-5
RouteState Highway 11
CountySkagit County
StateWashington
Coordinates48.48522, -122.33758
Functional classRural Major Collector

Condition and inspection

Fair

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

ComponentRatingMeaning
Deck6 SatisfactoryStructural elements show some minor deterioration.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionMay 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourBridge not over waterway
Structural evaluation6: Equal to present minimum criteria
Deck geometry4: Meets minimum tolerable limits to be left in place as is
Approach roadway alignment8: Equal to present desirable criteria
Operating rating71 US tons
Inventory rating42 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans4
Design loadHS 20
Structure length288 ft (87.8 m)
Longest span79 ft (24.1 m)
Deck width34 ft (10.5 m)
Roadway width31 ft (9.6 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic10,241 (2023)
Projected traffic15,295 by 2039
Trucks9%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesHighway
Detour if closed5 mi (8 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$5.7 million (2022 estimate)
NavigationNot applicable (no waterway)

Frequently asked questions

When was SR 11 over I-5 built?

It was built in 1959, making it 66 years old in 2025.

What condition is SR 11 over I-5 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 2023.

How much traffic does SR 11 over I-5 carry?

About 10,241 vehicles per day (2023 count), of which roughly 9% are trucks.

How long is SR 11 over I-5?

The structure is 288 ft (87.8 m) long with a longest span of 79 ft (24.1 m) and a deck 34 ft wide.

Who owns SR 11 over I-5?

It is owned by the State Highway Agency.