US Bridges

Mountain Loop Hwy. over Boardman Creek

Fair

Snohomish County, Washington · 16.9 E JCT SR 92 · Structure no. 082771000000000

Built
1952
73 years old
Condition
Fair
inspected July 2023
Type
Stringer/Multi-beam or Girder
Concrete Continuous
Length
90 ft
3 main spans
Daily traffic
1,666
2022 count
Owner
County
County Highway Agency

About this bridge

Mountain Loop Hwy. over Boardman Creek is a concrete continuous stringer/multi-beam or girder carrying Mountain Loop Hwy. over Boardman Creek in Snohomish County, Washington. It was built in 1952, so it is 73 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 1,666 vehicles a day, roughly 6% of them trucks, projected to reach 1,500 by 2045. The structure is 90 ft (27.4 m) long and 30 ft wide. If it were closed, the detour would be 93.8 mi (151 km).

Location

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CarriesMountain Loop Hwy.
CrossesBoardman Creek
Location16.9 E JCT SR 92
RouteCounty Highway 98960
CountySnohomish County
StateWashington
Coordinates48.06941, -121.68115
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.
Channel and channel protection4 PoorAdvanced section loss, deterioration, spalling or scour.
Last inspectionJuly 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 geometry4: Meets minimum tolerable limits to be left in place as is
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment6: Equal to present minimum criteria
Operating rating37 US tons
Inventory rating22 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialConcrete Continuous
DeckConcrete, cast-in-place
Main spans3
Design loadH 20
Structure length90 ft (27.4 m)
Longest span52 ft (15.8 m)
Deck width30 ft (9.1 m)
Roadway width26 ft (8 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic1,666 (2022)
Projected traffic1,500 by 2045
Trucks6%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed93.8 mi (151 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerCounty Highway Agency
Maintained byCounty Highway Agency
Historic statusNot eligible for the National Register of Historic Places
Work proposedReplacement because of substandard load-carrying capacity or roadway geometry
Estimated improvement cost$3.6 million (2022 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was Mountain Loop Hwy. over Boardman Creek built?

It was built in 1952, making it 73 years old in 2025.

What condition is Mountain Loop Hwy. over Boardman Creek 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 July 2023.

How much traffic does Mountain Loop Hwy. over Boardman Creek carry?

About 1,666 vehicles per day (2022 count), of which roughly 6% are trucks.

How long is Mountain Loop Hwy. over Boardman Creek?

The structure is 90 ft (27.4 m) long with a longest span of 52 ft (15.8 m) and a deck 30 ft wide.

Who owns Mountain Loop Hwy. over Boardman Creek?

It is owned by the County Highway Agency.