US Bridges

I Avenue over Guemes Channel

Fair

Skagit County, Washington · 0.41 N JCT SR 20 · Structure no. 081511000000000

Built
1925
100 years old, rebuilt 1976
Condition
Fair
inspected October 2024
Type
Movable - Lift
Steel
Length
205 ft
1 main span
Daily traffic
500
2020 count
Owner
County
County Highway Agency

About this bridge

I Avenue over Guemes Channel is a steel movable - lift carrying I Avenue over Guemes Channel in Skagit County, Washington. It was built in 1925 and reconstructed in 1976, so it is 100 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 500 vehicles a day, roughly 7% of them trucks, projected to reach 650 by 2040. The structure is 205 ft (62.5 m) long and 22 ft wide. If it were closed, the detour would be 98.8 mi (159 km).

Location

Open in Google Maps
CarriesI Avenue
CrossesGuemes Channel
Location0.41 N JCT SR 20
RouteCounty Highway 18410
CountySkagit County
StateWashington
Coordinates48.51866, -122.62347
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
Deck7 GoodSome minor problems.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection7 GoodSome minor problems.
Last inspectionOctober 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour within limits of footing or piles
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Deck geometry2: Basically intolerable, requiring high priority of replacement
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating27.9 US tons
Inventory rating21.4 US tons

Structure

Structure typeMovable - Lift
MaterialSteel
DeckConcrete, cast-in-place
Main spans1 (+1 approach)
Design loadHS 20
Structure length205 ft (62.5 m)
Longest span92 ft (28 m)
Deck width22 ft (6.6 m)
Roadway width15 ft (4.6 m)
Vertical clearance over deck16 ft (4.9 m)

Traffic and service

Average daily traffic500 (2020)
Projected traffic650 by 2040
Trucks7%
Lanes on structure1
Traffic directionOne-lane bridge for two-way traffic
CarriesHighway
CrossesWaterway
Detour if closed98.8 mi (159 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerCounty Highway Agency
Maintained byCounty Highway Agency
Historic statusHistorical significance not determinable at this time
Work proposedReplacement because of substandard load-carrying capacity or roadway geometry
Estimated improvement cost$5.3 million (2022 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was I Avenue over Guemes Channel built?

It was built in 1925, making it 100 years old in 2025. It was reconstructed in 1976.

What condition is I Avenue over Guemes Channel 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 October 2024.

How much traffic does I Avenue over Guemes Channel carry?

About 500 vehicles per day (2020 count), of which roughly 7% are trucks.

How long is I Avenue over Guemes Channel?

The structure is 205 ft (62.5 m) long with a longest span of 92 ft (28 m) and a deck 22 ft wide.

Who owns I Avenue over Guemes Channel?

It is owned by the County Highway Agency.