US Bridges

SR 305 over Agate Passage

Fair

Kitsap County, Washington · 6.8 N Bainbridge F/T · Structure no. 0003573A0000000

Built
1950
75 years old
Condition
Fair
inspected February 2023
Type
Truss - Thru
Steel
Length
1,229 ft
3 main spans
Daily traffic
21,431
2023 count
Owner
State
State Highway Agency

About this bridge

SR 305 over Agate Passage is a steel truss - thru carrying SR 305 over Agate Passage in Kitsap County, Washington. It was built in 1950, so it is 75 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 5 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 21,431 vehicles a day, roughly 5% of them trucks, projected to reach 29,862 by 2039. The structure is 1,229 ft (374.6 m) long and 34 ft wide. If it were closed, the detour would be 98.8 mi (159 km).

Location

Open in Google Maps
CarriesSR 305
CrossesAgate Passage
Location6.8 N Bainbridge F/T
RouteState Highway 305
CountyKitsap County
StateWashington
Coordinates47.71153, -122.56382
Functional classUrban Other Principal 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
Deck6 SatisfactoryStructural elements show some minor deterioration.
Superstructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection8 Very GoodNo problems noted.
Last inspectionFebruary 2023
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 geometry3: Basically intolerable, requiring high priority of corrective action
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating44 US tons
Inventory rating26 US tons

Structure

Structure typeTruss - Thru
MaterialSteel
DeckConcrete, cast-in-place
Main spans3 (+4 approach)
Design loadHS 20
Structure length1,229 ft (374.6 m)
Longest span540 ft (164.6 m)
Deck width34 ft (10.4 m)
Roadway width26 ft (7.9 m)
Vertical clearance over deck15 ft (4.6 m)

Traffic and service

Average daily traffic21,431 (2023)
Projected traffic29,862 by 2039
Trucks5%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway and pedestrian
CrossesHighway and waterway
Detour if closed98.8 mi (159 km)
TollOn a free road
National Highway SystemYes

Ownership and planned work

OwnerState Highway Agency
Maintained byState Highway Agency
Historic statusListed on the National Register of Historic Places
Work proposedRehabilitation because of general structure deterioration or inadequate strength
Estimated improvement cost$23.4 million (2022 estimate)
NavigationNavigation control on waterway (bridge permit required)

Frequently asked questions

When was SR 305 over Agate Passage built?

It was built in 1950, making it 75 years old in 2025.

What condition is SR 305 over Agate Passage 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 February 2023.

How much traffic does SR 305 over Agate Passage carry?

About 21,431 vehicles per day (2023 count), of which roughly 5% are trucks.

How long is SR 305 over Agate Passage?

The structure is 1,229 ft (374.6 m) long with a longest span of 540 ft (164.6 m) and a deck 34 ft wide.

Who owns SR 305 over Agate Passage?

It is owned by the State Highway Agency.