US Bridges

I-405 over May Creek

Good

King County, Washington · 1.8 N JCT SR 900 · Structure no. 0019242B0000000

Built
2023
2 years old
Condition
Good
inspected June 2023
Type
Stringer/Multi-beam or Girder
Prestressed Concrete
Length
166 ft
1 main span
Daily traffic
74,980
2023 count
Owner
State
State Highway Agency

About this bridge

I-405 over May Creek is a prestressed concrete stringer/multi-beam or girder carrying I-405 over May Creek in King County, Washington. It was built in 2023, so it is 2 years old, younger 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 8 out of 9. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

It carries about 74,980 vehicles a day, roughly 6% of them trucks, projected to reach 108,032 by 2039. The structure is 166 ft (50.6 m) long and 93 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

Open in Google Maps
CarriesI-405
CrossesMay Creek
Location1.8 N JCT SR 900
RouteInterstate 405
CountyKing County
StateWashington
Coordinates47.528, -122.19756
Functional classUrban Principal Arterial - Interstate

Condition and inspection

Good

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

ComponentRatingMeaning
Deck8 Very GoodNo problems noted.
Superstructure8 Very GoodNo problems noted.
Substructure8 Very GoodNo problems noted.
Channel and channel protection8 Very GoodNo problems noted.
Last inspectionJune 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation8: Equal to present desirable criteria
Deck geometry9: Superior to present desirable criteria
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating82.1 US tons
Inventory rating53.2 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans1
Design loadHL 93
Structure length166 ft (50.6 m)
Longest span164 ft (50 m)
Deck width93 ft (28.3 m)
Roadway width86 ft (26.1 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic74,980 (2023)
Projected traffic108,032 by 2039
Trucks6%
Lanes on structure4
Traffic directionOne-way traffic
CarriesHighway
CrossesWaterway
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 statusHistorical significance not determinable at this time
Work proposedRehabilitation because of general structure deterioration or inadequate strength
Estimated improvement cost$6.9 million (2022 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was I-405 over May Creek built?

It was built in 2023, making it 2 years old in 2025.

What condition is I-405 over May 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 2023.

How much traffic does I-405 over May Creek carry?

About 74,980 vehicles per day (2023 count), of which roughly 6% are trucks.

How long is I-405 over May Creek?

The structure is 166 ft (50.6 m) long with a longest span of 164 ft (50 m) and a deck 93 ft wide.

Who owns I-405 over May Creek?

It is owned by the State Highway Agency.