US Bridges

I-405 over Bn RR (abandoned)

Fair

King County, Washington · 1.3 N JCT I-90 · Structure no. 0008812A0000000

Built
1972
53 years old, rebuilt 1995
Condition
Fair
inspected September 2024
Type
Stringer/Multi-beam or Girder
Prestressed Concrete Continuous
Length
320 ft
3 main spans
Daily traffic
97,875
2023 count
Owner
State
State Highway Agency

About this bridge

I-405 over Bn RR (abandoned) is a prestressed concrete continuous stringer/multi-beam or girder carrying I-405 over Bn RR (abandoned) in King County, Washington. It was built in 1972 and reconstructed in 1995, 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 97,875 vehicles a day, roughly 6% of them trucks, projected to reach 145,688 by 2039. The structure is 320 ft (97.5 m) long and 67 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

Open in Google Maps
CarriesI-405
CrossesBn RR (abandoned)
Location1.3 N JCT I-90
RouteInterstate 405
CountyKing County
StateWashington
Coordinates47.59819, -122.17983
Functional classUrban Principal Arterial - Interstate

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 inspectionSeptember 2024
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 rating63.9 US tons
Inventory rating37 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialPrestressed Concrete Continuous
DeckConcrete, cast-in-place
Main spans3
Design loadHS 20 + Mod
Structure length320 ft (97.5 m)
Longest span106 ft (32.4 m)
Deck width67 ft (20.4 m)
Roadway width64 ft (19.5 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic97,875 (2023)
Projected traffic145,688 by 2039
Trucks6%
Lanes on structure5
Traffic directionOne-way traffic
CarriesHighway
CrossesOther
Detour if closed1.2 mi (2 km)
TollOn a free road
National Highway SystemYes
Strategic Highway NetworkInterstate STRAHNET route

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$10 million (2022 estimate)
NavigationNot applicable (no waterway)

Frequently asked questions

When was I-405 over Bn RR (abandoned) built?

It was built in 1972, making it 53 years old in 2025. It was reconstructed in 1995.

What condition is I-405 over Bn RR (abandoned) 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 September 2024.

How much traffic does I-405 over Bn RR (abandoned) carry?

About 97,875 vehicles per day (2023 count), of which roughly 6% are trucks.

How long is I-405 over Bn RR (abandoned)?

The structure is 320 ft (97.5 m) long with a longest span of 106 ft (32.4 m) and a deck 67 ft wide.

Who owns I-405 over Bn RR (abandoned)?

It is owned by the State Highway Agency.